Effects of Fasting & Time Restricted Eating on Fat Loss & Health

00:00:00.000 | - Welcome to the Huberman Lab Podcast,

00:00:02.260 | where we discuss science and science-based tools

00:00:04.900 | for everyday life.

00:00:05.900 | I'm Andrew Huberman,

00:00:10.320 | and I'm a professor of neurobiology and ophthalmology

00:00:13.140 | at Stanford School of Medicine.

00:00:15.140 | Today, we're talking all about fasting.

00:00:17.940 | And anytime we're talking about fasting,

00:00:20.220 | we are also talking about eating

00:00:22.020 | because we all need to eat sooner or later.

00:00:24.700 | We're going to talk about how fasting and when we eat

00:00:28.700 | influences a large range of aspects of our health

00:00:32.540 | and wellbeing, both physical and mental.

00:00:35.560 | So while nowadays,

00:00:36.700 | most people are familiar with the term intermittent fasting,

00:00:40.780 | also sometimes called time-restricted feeding,

00:00:43.940 | I think most people don't really understand

00:00:46.380 | how that process works.

00:00:48.100 | It's sort of obvious that intermittent fasting,

00:00:50.420 | AKA time-restricted feeding,

00:00:52.680 | involves eating at certain periods of each 24-hour cycle,

00:00:56.300 | or maybe even not eating for entire days in some cases.

00:01:00.160 | But if you think about it, everybody sleeps eventually,

00:01:03.760 | and therefore, because people don't eat during their sleep,

00:01:08.180 | almost everybody is employing some form

00:01:11.060 | of intermittent fasting or time-restricted feeding.

00:01:13.900 | What we're going to talk about today

00:01:15.380 | is how particular schedules of time-restricted feeding

00:01:19.900 | can impact our health in different ways.

00:01:22.300 | And when I say different ways,

00:01:23.780 | I mean, we're going to talk about how intermittent fasting,

00:01:27.300 | AKA time-restricted feeding, impacts weight loss,

00:01:30.860 | fat loss in particular,

00:01:32.740 | muscle maintenance and loss and gain,

00:01:35.780 | organ health, such as gut health and liver health,

00:01:39.080 | the genome, the epigenome, inflammation, sickness,

00:01:44.080 | recovery and healing from sickness,

00:01:47.100 | exercise, cognition, mood, and lifespan.

00:01:50.860 | So we're going to cover a tremendous amount of information.

00:01:53.380 | I promise to make it all directly accessible,

00:01:56.340 | regardless of whether or not you have a background

00:01:58.260 | in biology and metabolic science or not.

00:02:02.760 | I'm also going to talk about a lot of tools.

00:02:05.040 | In fact, I'm going to discuss a number of tools

00:02:07.580 | during today's episode that actually make it such

00:02:10.480 | that you don't have to follow any feeding schedule

00:02:14.660 | or fasting schedule, same thing if you think about it,

00:02:17.860 | in any absolutely strict regimented way,

00:02:22.600 | meaning if you were to only eat

00:02:25.100 | during an eight-hour period of each day, most of the time,

00:02:27.820 | but then occasionally eat

00:02:28.860 | across a 12-hour period of the day.

00:02:30.780 | In theory, that could actually have

00:02:33.780 | pretty serious detrimental health effects.

00:02:36.220 | And yet there are things that you can do

00:02:38.140 | to attenuate those negative effects.

00:02:40.260 | In fact, there are things that you can do and or take

00:02:43.460 | that can make it as if you did not eat at all.

00:02:46.540 | And so we'll discuss what those tools are.

00:02:48.900 | And in many cases for sake of health, weight loss,

00:02:51.620 | and performance, making the body think

00:02:54.440 | that it did not eat at all can actually be quite beneficial.

00:02:57.860 | So today we're going to cover mechanism

00:02:59.780 | and we're going to cover tools.

00:03:01.000 | Before we do that, I want to highlight a particular result

00:03:04.200 | that was published recently

00:03:05.240 | because it serves as a useful backbone

00:03:07.600 | as we wade into the conversation about fasting.

00:03:10.880 | This is a study that was published

00:03:12.880 | in the journal Cell Metabolism,

00:03:14.840 | a cell press journal, excellent journal.

00:03:17.120 | And the title of the paper is Fasting Blood Glucose

00:03:20.860 | as a Predictor of Mortality, Lost in Translation.

00:03:24.940 | And I'll explain what the lost

00:03:26.020 | in translation part means in a moment.

00:03:28.120 | But the basic takeaway of this study,

00:03:30.020 | and I should mention that the first author of the study

00:03:32.280 | is Paliyaguru, P-A-L-L-I-Y-A-G-U-R-U, guru.

00:03:37.280 | Paliyaguru et al, the basic finding of the study

00:03:44.140 | is that in humans, higher blood glucose

00:03:48.900 | is associated with mortality.

00:03:51.820 | And in fact, if you look at blood glucose,

00:03:54.260 | resting blood glucose across the lifespan,

00:03:56.560 | what you find is as people age,

00:03:58.740 | resting blood glucose goes up.

00:04:00.800 | Now, this is very interesting because for a long time,

00:04:03.780 | it was thought that metabolism actually goes down as we age.

00:04:06.900 | And to some extent that's true,

00:04:08.820 | but the reductions in metabolism are not nearly as robust

00:04:12.180 | as we once thought that they were across the lifespan.

00:04:15.040 | However, unless there's something done

00:04:17.940 | to mitigate the increase in blood glucose

00:04:20.180 | associated with aging,

00:04:21.820 | almost everybody experiences a gradual

00:04:25.540 | but regular increase in resting blood glucose

00:04:28.220 | that predicts mortality.

00:04:30.320 | Now, the title, as I mentioned,

00:04:31.700 | is Fasting Blood Glucose as a Predictor of Mortality

00:04:34.660 | Lost in Translation.

00:04:35.940 | And the reason that they included lost in translation

00:04:38.580 | in the title is that what I just told you

00:04:41.260 | that increases in resting blood glucose predict mortality

00:04:44.620 | or are correlated with mortality is true

00:04:47.220 | for human beings and for non-human primates, monkeys,

00:04:50.860 | but the opposite is true in mice.

00:04:53.700 | And so I thought it was important to use this study

00:04:56.720 | as an example of where studies in mice often,

00:05:00.040 | but not always translate to humans and to non-human primates.

00:05:04.180 | So today I'm going to be careful to distinguish

00:05:06.260 | when a study was performed in mice versus in humans,

00:05:08.980 | because it seems that at least when discussing feeding,

00:05:13.700 | blood glucose, and other aspects of diet

00:05:15.880 | as they relate to health and wellbeing,

00:05:18.140 | whether or not a study was performed in rodents

00:05:21.020 | or in humans can be very important.

00:05:23.860 | In this case, the results were directly 180 degrees

00:05:27.700 | opposite to one another.

00:05:29.060 | In other words, in mice, resting blood glucose went down

00:05:32.520 | and it was associated with mortality.

00:05:34.560 | So lower blood glucose associated with mortality,

00:05:36.600 | whereas in humans, higher resting blood glucose

00:05:38.940 | was associated with mortality.

00:05:40.220 | And obviously what we're mostly interested in

00:05:43.140 | is health and wellbeing of ourselves, of humans.

00:05:46.160 | I'm sure there are some people out there

00:05:47.300 | that are intensely concerned

00:05:49.060 | about the health and wellbeing of mice,

00:05:50.580 | which you could imagine a few rare contexts

00:05:53.740 | where that's important,

00:05:54.580 | but obviously most of us are interested in human health.

00:05:57.180 | So I'll be sure to emphasize when studies were performed

00:06:00.100 | in humans versus in mice.

00:06:02.180 | Before we begin, I'd like to emphasize that this podcast

00:06:04.920 | is separate from my teaching and research roles at Stanford.

00:06:07.920 | It is, however, part of my desire and effort

00:06:10.060 | to bring zero cost to consumer information about science

00:06:12.640 | and science related tools to the general public.

00:06:15.620 | In keeping with that theme,

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00:11:23.120 | Okay, so let's talk about feeding, fasting,

00:11:25.780 | health, and performance.

00:11:28.140 | And I want to just establish a few foundational terms

00:11:32.220 | so that we're all on the same page.

00:11:34.100 | First of all,

00:11:34.940 | rather than talk about fasting or time-restricted feeding,

00:11:38.340 | I'm largely going to talk about time-restricted feeding,

00:11:41.040 | but please understand that time-restricted feeding

00:11:44.040 | is just one side of the coin that is a two-sided coin

00:11:48.080 | that includes fasting on the one hand, not eating,

00:11:50.800 | and time-restricted feeding on the other hand.

00:11:53.060 | I may occasionally say fasting,

00:11:55.140 | but because fasting and eating establish

00:11:58.340 | different biological conditions in the body,

00:12:00.920 | time-restricted feeding is the term that I will use

00:12:03.840 | to describe the overall plan

00:12:06.840 | of restricting one's eating window, as it's called,

00:12:10.040 | to a particular phase of each 24 hour day,

00:12:13.820 | or in some cases to particular days within the week,

00:12:18.220 | because as you'll soon learn,

00:12:19.860 | there are aspects of time-restricted feeding, aka fasting,

00:12:23.900 | that involve eating every other day

00:12:26.300 | or eating one way for five days

00:12:28.860 | and then fasting for two days and so forth.

00:12:31.180 | So I'll be very precise about what I mean and why I mean it,

00:12:35.180 | but for the time being,

00:12:36.420 | I'm going to refer to time-restricted feeding

00:12:40.240 | as a way to put an umbrella over this conversation.

00:12:43.800 | Second of all,

00:12:44.900 | I am going to emphasize a lot of biological mechanism.

00:12:48.180 | If you've listened to this podcast before,

00:12:50.620 | you know that I always begin with biological mechanism.

00:12:53.940 | I do describe tools of how to implement those mechanisms,

00:12:57.260 | but I wholeheartedly believe that knowing mechanisms

00:13:01.020 | and understanding how these processes work

00:13:03.800 | gives you tremendous flexibility and understanding

00:13:07.700 | and control over the processes

00:13:10.080 | of your mental and physical health.

00:13:11.500 | Whereas if I were to just list off a menu of things to do

00:13:15.300 | and not to do, those will work,

00:13:18.280 | but those will not give you the kind of understanding

00:13:22.080 | that would allow you to navigate through life,

00:13:24.380 | through travel, through dinners out,

00:13:27.140 | through different exercise schedules,

00:13:29.760 | whether or not you're one age or another age,

00:13:31.500 | male, female, et cetera,

00:13:33.580 | I'm giving you mechanisms so that you can gain more control

00:13:36.560 | over the systems in your brain and body.

00:13:39.320 | Everything's timestamped,

00:13:40.320 | so if you want to jump to the to-dos,

00:13:41.980 | you can certainly do that,

00:13:43.220 | but I encourage you to hang in there for the mechanism bit.

00:13:46.700 | I will make it all very clear

00:13:48.120 | because if you understand mechanism,

00:13:50.020 | you are in a true place of power

00:13:51.700 | and control over your biology.

00:13:53.800 | If ever there was a topic that is controversial,

00:13:56.680 | especially on the internet,

00:13:58.000 | it is that of diet and nutrition.

00:14:00.720 | So I'm wading into this with a smile

00:14:03.660 | and in eager anticipation of all the,

00:14:06.420 | but, but, but this, and but, but that, and wait,

00:14:09.120 | but this showed that.

00:14:10.820 | Here's the deal.

00:14:11.900 | We need to precisely define what it is

00:14:14.860 | that we're talking about when we talk about nutrition.

00:14:18.100 | I'm going to give you an example of a study

00:14:20.160 | that was published a few years ago, 2018,

00:14:22.760 | by a colleague of mine at Stanford, Chris Gardner.

00:14:26.540 | So he's a terrific professor of nutrition

00:14:29.900 | and has done a lot of important studies

00:14:32.300 | on how nutrition impacts different aspects of health.

00:14:36.320 | This is a large scale study.

00:14:37.980 | It was published in JAMA,

00:14:39.620 | the Journal of the American Medical Association,

00:14:41.620 | one of the very top tier journals in the area of medicine.

00:14:45.660 | And certainly for a paper on nutrition to show up there

00:14:48.540 | meant that it had to meet an exceedingly high standard.

00:14:51.340 | This paper where Chris is the first author,

00:14:56.240 | it's Gardner et al, 2018 JAMA,

00:14:58.460 | looked at weight loss in people following

00:15:03.780 | one particular diet versus another particular diet.

00:15:06.980 | And this was a 12 month weight loss study.

00:15:09.500 | So it was focused specifically on weight loss,

00:15:12.140 | although they looked at some other parameters as well.

00:15:14.580 | And the basic conclusion of the study was that

00:15:17.620 | there was no significant difference in weight change

00:15:20.300 | between people following a healthy low fat diet

00:15:23.540 | versus a healthy low carbohydrate diet

00:15:25.760 | with significantly more dietary fats in them.

00:15:28.220 | This caused a lot of ripples in the world of nutrition

00:15:33.700 | and nutritional science,

00:15:35.020 | and certainly in the general population,

00:15:37.380 | because anyone that understands diet and nutrition

00:15:41.020 | would immediately say, but wait,

00:15:42.940 | there are all sorts of different implications

00:15:45.020 | of eating one type of diet,

00:15:46.980 | say low carbohydrate, higher fats,

00:15:49.100 | versus a higher carbohydrate, lower fat diet.

00:15:52.100 | And indeed there are.

00:15:53.560 | This study was focused specifically on fat loss

00:15:57.220 | and on weight loss.

00:15:58.980 | So as we discuss time restricted feeding,

00:16:03.340 | we need to be very precise about what are the effects

00:16:06.060 | of time restricted feeding and of eating

00:16:08.500 | in particular ways at particular times,

00:16:11.580 | we are going to emphasize again,

00:16:13.140 | whether or not the study was done in mice or in humans

00:16:15.900 | and athletes and men and women or both.

00:16:18.460 | But the study from Gardner and colleagues

00:16:20.740 | is a beautiful study and really emphasizes that

00:16:23.680 | if one's main goal is simply to lose weight,

00:16:27.640 | then it really does not matter what one eats,

00:16:31.940 | provided that the number of calories burned

00:16:35.340 | is higher than the number of calories ingested.

00:16:38.140 | However, anyone out there who understands

00:16:41.900 | a little bit of biology or a lot of biology will agree

00:16:45.960 | that there are many factors that impact

00:16:48.340 | that calories burned part of the equation.

00:16:50.960 | Some of those are obvious.

00:16:52.340 | So for instance, amount of exercise,

00:16:55.220 | type of exercise, basal metabolic rate,

00:16:57.860 | how much energy one burns just sitting there.

00:17:00.540 | I've talked before on this podcast about meat,

00:17:02.540 | non-exercise induced thermogenesis,

00:17:04.740 | where if people bounce around a lot and fidget a lot,

00:17:07.240 | they can burn anywhere from 800 to 2000 calories per day.

00:17:11.020 | So their quote unquote basal metabolic rate

00:17:13.520 | is actually much higher simply because they're fidgeters.

00:17:15.580 | Whereas people who tend to be more stationary

00:17:17.320 | have a lower basal metabolic rate on average.

00:17:19.780 | There's great science to support this.

00:17:21.780 | Metabolic factors and hormones are also very important.

00:17:27.160 | Hormones such as thyroid hormone and insulin

00:17:30.360 | and growth hormone and the sex story to hormones,

00:17:32.560 | testosterone and estrogen,

00:17:34.260 | those levels will also profoundly influence

00:17:37.000 | the calories out the calories of burned component

00:17:39.680 | of the calories in calories out equation.

00:17:42.500 | So if out there on the internet

00:17:45.420 | or in listening to a particular podcast or speaker,

00:17:48.300 | somebody says, this is the ideal diet

00:17:50.820 | or calories in calories out does not matter

00:17:53.660 | or calories in calories out is the only thing that matters.

00:17:56.460 | I think it's very important to understand

00:17:58.100 | that there are some foundational truths

00:17:59.960 | such as calories in calories out,

00:18:01.940 | but that of course hormone factors

00:18:04.960 | and the context in which a given diet regimen

00:18:08.660 | is taking place are exceedingly important.

00:18:11.180 | A good example of this would be puberty.

00:18:14.120 | At that time in life, sex story hormones

00:18:17.100 | are changing profoundly in the body

00:18:18.680 | as our growth hormone and other hormones.

00:18:21.220 | And much of caloric intake is directed

00:18:24.460 | towards protein synthesis,

00:18:26.220 | towards the production of muscle and bone

00:18:27.860 | and other tissues of the body.

00:18:29.220 | And that's because of changes in hormones

00:18:31.100 | that we call puberty.

00:18:32.460 | So there's no way that we can drill into every aspect

00:18:36.560 | of a given feeding plan or feeding schedule

00:18:41.480 | that would allow us to tap into every aspect

00:18:43.880 | of the list that I read out before weight loss,

00:18:46.680 | fat loss, muscle, organ, genome, epigenome,

00:18:48.660 | inflammation, exercise, cognition, mood, and lifespan.

00:18:51.500 | But today we're going to be very precise

00:18:53.080 | about how time restricted feeding.

00:18:55.980 | It's very clear from both animal studies

00:18:58.440 | and human studies can have a very powerful

00:19:02.040 | and positive impact on everything from weight loss

00:19:06.080 | and fat loss to various health parameters.

00:19:09.540 | This is a beautiful literature that's emerged mostly

00:19:12.820 | in the last 10 or 15 years.

00:19:15.020 | And as we march into this literature,

00:19:16.680 | what you'll see is that there actually is a perfect diet

00:19:20.160 | for you on a given day.

00:19:23.240 | And that perfect diet for you on a given day is contextual,

00:19:27.800 | meaning it depends on what you did yesterday

00:19:30.640 | and what you're going to do tomorrow.

00:19:32.920 | So there is a perfect diet for you.

00:19:34.960 | And today I'm going to arm you with the mechanisms

00:19:37.080 | and understanding that will allow you to define

00:19:39.440 | what that perfect diet is and will allow you to eat

00:19:43.160 | on a schedule and to eat the things

00:19:45.800 | that are going to best serve your goals.

00:19:48.200 | So let's talk about eating and what happens when you eat.

00:19:51.360 | And let's talk about fasting or not eating

00:19:54.360 | and what happens when you fast.

00:19:55.880 | I did an entire episode on eating and metabolism

00:19:59.960 | and hormones and other factors that impact appetite.

00:20:03.640 | We don't have time to go into all those details now,

00:20:05.640 | although you're welcome to listen to that episode as well.

00:20:08.480 | But we can briefly describe the overall conditions

00:20:13.480 | that are set in the body when we eat and when we don't eat.

00:20:17.560 | The key word here is conditions.

00:20:21.100 | If I can emphasize anything today,

00:20:23.320 | it's that what you eat and when you eat it,

00:20:26.800 | set conditions in your body.

00:20:29.440 | And those conditions can be very good for you

00:20:31.720 | or very bad for you, depending on when you eat.

00:20:35.760 | In fact, when you eat is as important as what you eat.

00:20:40.760 | I'll repeat that.

00:20:42.580 | When you eat is as important as what you eat,

00:20:44.800 | at least as it relates to health parameters,

00:20:47.040 | in particular, liver health and mental health.

00:20:50.320 | Some simple rules about eating.

00:20:52.520 | First of all, when you eat, typically your blood glucose,

00:20:56.520 | your blood sugar will go up.

00:20:59.160 | Also insulin levels will go up.

00:21:01.280 | Insulin is a hormone that's involved in mobilizing glucose

00:21:04.520 | from the bloodstream.

00:21:06.320 | How much your glucose and insulin go up depends

00:21:10.220 | on what you eat and how much you eat.

00:21:12.840 | In general, simple sugars, including fructose from fruit,

00:21:17.840 | but also sucrose and glucose and simple sugars

00:21:21.000 | will raise your insulin and blood glucose

00:21:23.240 | more than complex carbohydrates,

00:21:26.280 | things like grains and breads and pastas and so forth.

00:21:28.920 | And grains and breads and pastas and so forth

00:21:31.200 | will raise your blood glucose more

00:21:32.920 | than fibrous carbohydrates like lettuce and broccoli

00:21:36.280 | and things of that sort.

00:21:38.160 | Protein has a somewhat moderate or modest impact

00:21:41.880 | on insulin and glucose and fat has the lowest impact

00:21:45.560 | on raising your blood glucose and blood insulin.

00:21:48.760 | So what you eat will impact how steep arise

00:21:52.600 | in blood glucose and insulin takes place.

00:21:55.440 | And there are a number of factors that are related

00:21:57.980 | to your individual health that will also dictate how steep

00:22:01.160 | and how high that rise in glucose and insulin will be.

00:22:04.520 | For the time being, I'm leaving out people

00:22:07.080 | who have type one diabetes.

00:22:08.360 | These are people that don't manufacture their own insulin

00:22:10.920 | and type two diabetes is essentially insulin insensitivity,

00:22:15.920 | lack of sensitivity to insulin,

00:22:18.520 | which leads to high blood glucose.

00:22:20.840 | But when you eat blood glucose goes up

00:22:23.800 | and when you don't eat blood glucose and insulin go down.

00:22:27.660 | The longer it's been since your last meal,

00:22:29.840 | the lower typically your blood glucose and insulin will be.

00:22:33.600 | And the higher things like GLP-1 glucagon,

00:22:38.120 | like peptide one glucagon being a hormone

00:22:42.880 | that's also secreted when you are in a fasted state

00:22:46.560 | or a low blood glucose state.

00:22:49.260 | It's involved in mobilizing various energy sources

00:22:53.160 | from the body, including fat through what we call lipolysis.

00:22:57.120 | Also using carbohydrates and potentially even using muscle

00:22:59.960 | as a source of energy.

00:23:01.240 | So that's kind of a fire hose of information

00:23:06.240 | about what happens when you eat and don't eat.

00:23:08.100 | But just think of it this way,

00:23:09.640 | blood sugar and insulin go up when you eat,

00:23:11.980 | they go down when you don't eat

00:23:13.300 | and other hormones go up when you don't eat.

00:23:16.180 | So there are hormones associated with the fasted state

00:23:19.320 | and there are hormones associated with the eating

00:23:22.040 | and having just eaten state.

00:23:25.000 | Now, the most important thing to understand

00:23:28.520 | is that like everything in biology,

00:23:31.480 | this is a process that takes time.

00:23:34.320 | So insulin and glucose go up when we eat

00:23:37.560 | and it takes some period of time for them to go down.

00:23:39.980 | Even if we stop eating,

00:23:42.020 | they will remain up for some period of time

00:23:44.120 | and then go back down.

00:23:45.460 | It takes time.

00:23:47.360 | This is very important because if you look

00:23:49.760 | at the scientific literature on fasting,

00:23:52.720 | on time restricted feeding, it's absolutely clear

00:23:56.940 | that the health benefits,

00:23:58.920 | not just the weight loss benefits,

00:24:00.400 | but that the health benefits from time restricted feeding

00:24:03.600 | occur because certain conditions are met in the brain

00:24:06.940 | and body for a certain amount of time.

00:24:10.320 | And that gives us an anchor from which to view

00:24:14.320 | what eating is in terms of how it sets conditions

00:24:17.720 | in the body over time.

00:24:19.600 | And if that sounds overly analytic,

00:24:22.160 | I promise you this is the simplest and best way

00:24:24.760 | to think about any eating schedule or any eating plan.

00:24:28.500 | So I think it's fair to say that in the field of nutrition,

00:24:31.740 | there are a few landmark studies

00:24:34.120 | that serve as really strong anchors

00:24:36.160 | for building our understanding of what to eat

00:24:39.200 | and what not to eat and when to eat,

00:24:40.640 | depending on our goals.

00:24:42.320 | The Garner study that I mentioned earlier

00:24:44.320 | is one such study in that it says,

00:24:47.520 | if your goal is weight loss,

00:24:49.400 | it really does not matter what foods you consume

00:24:53.440 | provided that you consume a sub maintenance caloric diet.

00:24:57.880 | However, I want to emphasize again,

00:25:00.440 | that sets aside issues of adherence,

00:25:04.200 | meaning how easy or hard it is to adhere to a given diet.

00:25:07.640 | Some people find it much easier to follow a high fat,

00:25:10.180 | low carbohydrate diet.

00:25:11.200 | Some people follow a different diet

00:25:13.160 | because it's much easier for them to follow.

00:25:15.560 | And some people are concerned with mental performance

00:25:17.960 | and athletic performance.

00:25:18.960 | So that study doesn't say there's a best diet.

00:25:22.100 | What it says is that what you consume is less important

00:25:26.420 | than the amount of food that you consume,

00:25:28.600 | at least for sake of weight loss,

00:25:30.960 | not necessarily for sake of health.

00:25:33.640 | Now, the study that I'm going to refer to next

00:25:36.920 | is what I would consider the second major pillar

00:25:39.900 | of nutritional studies.

00:25:41.020 | This is a truly landmark study that was carried out

00:25:44.440 | by Sachin Panda, who is a professor

00:25:47.680 | at the Salk Institute of Biological Studies in San Diego,

00:25:50.500 | an absolutely phenomenal institution

00:25:52.860 | and an absolutely phenomenal researcher.

00:25:55.260 | I've known Sachin for a number of years.

00:25:56.920 | And I want to emphasize that the current literature

00:26:00.600 | on intermittent fasting and time restricted feeding

00:26:03.700 | can largely be attributed to Sachin

00:26:07.040 | and the work that he's done.

00:26:08.180 | There are others involved too, of course.

00:26:10.920 | And of course, time restricted feeding and fasting

00:26:13.260 | has a rich history that goes back many hundreds,

00:26:16.320 | if not thousands of years in different cultures

00:26:18.320 | and religions, but the science of time restricted feeding

00:26:21.520 | can really mainly be attributed to the incredible work

00:26:24.280 | that Sachin has done.

00:26:25.620 | And I'm grateful to consider him a friend and a colleague.

00:26:29.560 | And we consulted at length in anticipation of this episode.

00:26:32.520 | I also hope to have him on as a guest in the future.

00:26:35.160 | The landmark paper that came from Sachin's lab

00:26:37.760 | was published in 2012.

00:26:39.800 | This was a paper in mice that set the basis

00:26:42.860 | for studies in humans that came later.

00:26:44.920 | And the title of this paper is time restricted feeding

00:26:47.960 | without reducing caloric intake prevents metabolic diseases

00:26:52.040 | in mice fed a high fat diet.

00:26:54.640 | So the title tells us a lot.

00:26:56.480 | It says that what's varied in this study

00:26:59.320 | is not what these mice ate.

00:27:01.860 | It was when they ate it.

00:27:03.940 | And there were essentially four conditions in this study

00:27:06.760 | and the results are absolutely remarkable.

00:27:09.580 | So I'm going to walk you through the major results.

00:27:12.400 | What they did is they gave mice access

00:27:15.540 | to different types of food.

00:27:17.460 | There were four groups.

00:27:18.840 | One group of mice had access to just a normal mouse diet.

00:27:23.420 | It would not be a diet that you'd be very interested in.

00:27:25.800 | I confess I've actually tasted mouse chow.

00:27:27.720 | If you work with mice at all,

00:27:28.800 | you just have to do it at least once.

00:27:30.480 | It doesn't taste very good.

00:27:31.400 | It tastes like a very bland graham cracker cookie.

00:27:33.620 | And I confess that I only had the tiniest little bit,

00:27:35.680 | but mice like that stuff.

00:27:37.400 | And if you allow them to eat that stuff,

00:27:39.360 | what's called ad libitum, whenever they want,

00:27:41.540 | you just keep it in their food 24 hours a day,

00:27:43.980 | they will eat sometimes

00:27:45.200 | and then they won't eat it at other times.

00:27:46.940 | Or in this case, they also had a condition

00:27:49.760 | where they gave them mouse chow in a time restricted way,

00:27:52.840 | just for a certain number of hours each day,

00:27:56.160 | about eight hours.

00:27:57.580 | Or they gave them a high fat diet that was a separate group,

00:28:02.280 | got a high fat diet at any time they wanted.

00:28:04.820 | So this was kind of the carnival for mice

00:28:06.700 | because mice really like high fat, highly palatable foods.

00:28:09.640 | And so they got a lot of goodies and high fat in their food.

00:28:13.240 | And then there was a fourth group

00:28:14.520 | that had access to the high fat diet

00:28:16.640 | as much as they wanted to eat,

00:28:17.920 | but only during a restricted time period

00:28:20.900 | of each 24 hour cycle.

00:28:22.400 | Now mice are nocturnal, humans are what we call diurnal.

00:28:25.960 | Actually, we're not really diurnal, we're crepuscular,

00:28:28.320 | which means that we're most active in the morning

00:28:30.460 | and in the evening, not so much in the afternoon.

00:28:32.820 | But nonetheless, everything I'm going to tell you

00:28:37.160 | is true also for humans.

00:28:39.180 | And we know this now from human studies.

00:28:41.120 | One of the most important things to take away from the study

00:28:43.560 | was that mice that ate a highly palatable, high fat diet,

00:28:47.300 | a great tasting diet,

00:28:48.600 | but only during a restricted feeding window

00:28:50.720 | of each 24 hour cycle maintained or lost weight over time.

00:28:55.720 | Whereas mice that ingested the same diet,

00:28:59.080 | same amount of calories,

00:29:01.800 | but had access to those calories around the clock,

00:29:05.260 | gained weight, became obese and quite sick.

00:29:08.640 | And as an additional second point,

00:29:10.860 | the mice that restricted their feeding window

00:29:13.680 | to a particular portion of eight hours

00:29:16.400 | of every 24 hour cycle actually showed some improvement

00:29:21.320 | in important health markers.

00:29:23.360 | And what was even more incredible is that mice

00:29:26.880 | that only ate during a particular feeding window

00:29:29.300 | also experienced some reversal

00:29:32.920 | of some prior negative health effects.

00:29:35.560 | So this study really lit up the world

00:29:38.300 | and got people excited about time restricted eating.

00:29:41.100 | Again, they used an eight hour feeding window.

00:29:45.260 | The story around that eight hour feeding window

00:29:48.340 | is kind of interesting though.

00:29:49.920 | Not many people know this

00:29:50.900 | because it wasn't included in the paper

00:29:52.880 | and there was no reason to include it in the paper.

00:29:55.320 | Not to out anybody,

00:29:57.980 | but it turns out that the reason

00:29:59.700 | they used an eight hour feeding window

00:30:01.600 | and not a nine hour or a 10 hour feeding window

00:30:04.460 | is because studies of this sort are actually quite demanding

00:30:08.940 | to perform and require the constant presence

00:30:12.080 | of the graduate student or postdoc there

00:30:14.700 | to ensure that the food is in the cages at particular times

00:30:18.140 | and not in the cages at other times.

00:30:20.260 | And mice are really good at hiding food.

00:30:22.100 | They'll even hide food in their jowls.

00:30:24.060 | And so there's a lot of work that has to be done

00:30:27.420 | to prepare for that eight hour feeding window

00:30:29.620 | and to make sure after that eight hour feeding window,

00:30:32.680 | there's all the food has been removed from the cage

00:30:35.020 | and from the jowls of the mice and so forth.

00:30:37.060 | And it turns out that the significant other

00:30:39.780 | of the graduate student and or postdoc,

00:30:42.420 | I won't reveal who they were running this study,

00:30:45.220 | forbid their significant other, the scientist,

00:30:48.940 | from being in the lab for periods of time

00:30:52.060 | that were much longer than the 10 or 12 hours

00:30:54.240 | that were required in order to ensure

00:30:56.500 | this eight hour feeding window.

00:30:58.140 | So when we hear the eight hour feeding windows are holy,

00:31:01.120 | they are not holy.

00:31:02.160 | And later we are going to talk about how eating for a time

00:31:06.540 | that's restricted to eight hours versus 10 hours

00:31:08.620 | versus 12 hours, for instance,

00:31:10.860 | how that impacts various parameters like health parameters

00:31:14.300 | and weight loss, et cetera.

00:31:15.300 | But the eight hour feeding window was actually created

00:31:17.740 | because of a real world constraint on the research

00:31:20.060 | and the relationship with the researcher

00:31:21.820 | performing the research,

00:31:22.940 | not because there's anything holy

00:31:24.560 | about an eight hour feeding window.

00:31:26.460 | Now, an important point about when the feeding window falls

00:31:29.940 | within the 24 hour cycle,

00:31:31.920 | it is very important that the feeding window fall

00:31:34.900 | during the more active phase of one's day.

00:31:38.920 | So for humans, that's typically in the early part of the day

00:31:42.860 | or the later part of the day, but not at night.

00:31:45.540 | Put very simply, there are a lot of data now

00:31:48.500 | pointing to the fact that eating during the nocturnal phase

00:31:53.040 | of the 24 hour cycle is very detrimental to one's health.

00:31:57.980 | In fact, when we eat can either enhance our health

00:32:02.360 | or can diminish our health.

00:32:04.840 | When we see light can enhance our feelings of wellbeing

00:32:08.840 | or can diminish our feelings of wellbeing.

00:32:10.540 | I've talked many times before about this

00:32:12.160 | on the Huberman Lab podcast that during the daytime,

00:32:14.400 | you want to get as much sunlight

00:32:16.320 | and other types of bright light in your eyes

00:32:18.000 | as is safely possible.

00:32:19.280 | And then you want to avoid light

00:32:21.080 | in the middle of the night.

00:32:22.320 | It has detrimental dopamine lowering effects,

00:32:24.960 | can cause depression, cortisol increases, et cetera.

00:32:27.840 | So when you view light is as important

00:32:30.200 | as the light that you view and when you eat

00:32:33.100 | is as important as what you eat.

00:32:36.980 | In this study, they saw something really interesting,

00:32:40.460 | which was that not only did restricting food

00:32:43.780 | to a particular phase of the 24 hour cycle

00:32:46.420 | benefit things like lean body mass and fat loss

00:32:50.960 | and a number of health parameters

00:32:52.280 | that I'll talk about in a moment,

00:32:53.840 | but it also anchored all the gene systems of the body

00:32:57.880 | and provided a more regular stable so-called circadian rhythm

00:33:01.720 | or 24 hour rhythm.

00:33:03.060 | You may be surprised to learn that 80%,

00:33:06.100 | 80% of the genes in your body and brain

00:33:10.240 | are on a 24 hour schedule.

00:33:13.840 | That is they change their levels going from high to low

00:33:16.980 | and back to high again across the 24 hour cycle.

00:33:19.840 | And when those genes are high at the appropriate times

00:33:22.740 | and low at the appropriate times,

00:33:24.200 | meaning their expression is high and low

00:33:26.560 | at the appropriate times.

00:33:28.080 | And therefore the proper RNAs and proteins are made

00:33:31.300 | because DNA encodes for RNA.

00:33:32.760 | RNA is translated into proteins.

00:33:34.540 | When that happens, your health benefits.

00:33:39.840 | When those genes are not expressed at the right times,

00:33:42.940 | when they're high or low at the wrong times

00:33:45.380 | of each 24 hour cycle,

00:33:46.700 | that's when you get negative health effects.

00:33:48.920 | This study showed that when mice restrict their eating

00:33:52.240 | to an eight hour period within the most active phase

00:33:56.120 | of their 24 hour cycle,

00:33:57.600 | many of the genes that are associated

00:34:00.420 | with these so-called circadian and clocks,

00:34:02.420 | these genes have names like PER, BMAL, CRY1, et cetera.

00:34:06.640 | Those so-called clock genes underwent

00:34:09.560 | a very regular entrainment,

00:34:11.840 | a locking in to the proper 24 hour schedule.

00:34:15.240 | And while this was in mice,

00:34:16.540 | we now know that this also occurs in humans.

00:34:19.740 | I've said before on this podcast, and I'll say it again,

00:34:22.240 | that light and when we view light is the primary way

00:34:25.180 | in which these genes and the clock systems of our body

00:34:28.020 | get organized or entrained,

00:34:29.860 | meaning matched to the outside light dark cycle.

00:34:32.280 | So viewing light early in the day and in the afternoon

00:34:34.740 | and as much as possible all day, great.

00:34:36.900 | Ideally that sunlight.

00:34:38.320 | Avoiding light in the middle of the night is also great.

00:34:41.120 | It's great because it causes the increases

00:34:45.620 | in particular genes and the decreases in particular genes

00:34:47.900 | in every cell throughout your body

00:34:49.240 | at the appropriate times.

00:34:51.040 | The second most powerful timekeeper or zeitgeber

00:34:54.300 | as it's called is food and when you eat.

00:34:58.660 | And in this study, the results they saw underscore

00:35:02.620 | this point, what they saw is that the peaks

00:35:04.680 | in these clock genes became very regular

00:35:07.800 | and the dips in these clock genes became very regular.

00:35:10.600 | And that led to a whole host of really important

00:35:14.560 | positive health effects.

00:35:16.800 | Conversely, when mice ate whenever they wanted

00:35:19.660 | across the 24 hour cycle,

00:35:21.500 | these clock genes became really out of whack

00:35:24.160 | and the negative health consequences

00:35:26.860 | were the downstream result of these changes

00:35:30.220 | in these clock genes.

00:35:31.400 | This has now also been shown to be true for humans.

00:35:35.100 | So if you want to be healthy, you want your organ health,

00:35:38.100 | your metabolic health to be entrained properly.

00:35:42.400 | One of the most important things you can do

00:35:43.820 | is to view light at the appropriate times

00:35:45.220 | of each 24 hour schedule and to not view light

00:35:47.460 | at other times of that schedule

00:35:49.060 | and to eat at the appropriate time of each 24 hour day.

00:35:53.720 | Now, again, there are rare instances that we will discuss

00:35:56.500 | when skipping entire days or entire 24 hour cycles

00:36:00.460 | of eating can be beneficial.

00:36:01.940 | But for now we're talking about schedules

00:36:04.320 | of time restricted feeding that involve a window of feeding

00:36:07.640 | that falls during your more active phase.

00:36:09.540 | So during the daytime, putting aside people

00:36:12.480 | that work shift work during the daytime

00:36:14.360 | is when you want to eat.

00:36:15.920 | And this eight hour feeding window

00:36:18.220 | provided a very strong reinforcing signal

00:36:22.040 | that combines with light to ensure that these genes

00:36:24.680 | are expressed at the appropriate times.

00:36:27.120 | The short takeaway from this

00:36:28.360 | is you probably want to think about

00:36:31.200 | and perhaps even engage in time restricted feeding.

00:36:34.240 | So as I mentioned earlier,

00:36:35.320 | when mice can eat around the clock, bad things happen.

00:36:38.360 | And one of the bad things that happens

00:36:39.900 | is that the liver suffers.

00:36:42.580 | The liver is involved in all sorts of things,

00:36:45.260 | production of important hormones and other factors

00:36:47.840 | related to metabolism.

00:36:49.640 | And when mice can eat around the clock,

00:36:51.820 | their livers got very sick, fatty deposits in the liver,

00:36:55.520 | other factors in the liver,

00:36:56.920 | essentially taking down the pathway of liver disease.

00:37:00.000 | The time restricted feeding essentially reversed that

00:37:03.480 | or led in many cases to even healthier liver conditions.

00:37:06.760 | And that's based on this study,

00:37:07.800 | but also additional studies also now in humans.

00:37:11.640 | So restricting your feeding to a particular window

00:37:14.180 | every 24 hour cycle has clearly been shown now in mice

00:37:17.460 | and in humans to enhance liver health, which is wonderful.

00:37:21.880 | How does it do this?

00:37:24.240 | Well, it happens because food intake,

00:37:27.540 | as I mentioned earlier,

00:37:28.480 | sets certain conditions in the body

00:37:30.540 | that lasts for a period of time.

00:37:32.760 | Anytime we eat, whether or not we are a mouse or a human,

00:37:36.140 | there's a period of time

00:37:37.340 | that's required for so-called digestion,

00:37:39.820 | but also gastric emptying

00:37:41.680 | and other processes related to breaking down that food

00:37:44.540 | and utilizing it.

00:37:45.660 | And that is an active process.

00:37:47.360 | It requires energy.

00:37:49.280 | And that process of breaking down food

00:37:53.780 | involves certain cellular functions

00:37:55.980 | that if they're ongoing throughout the 24 hour cycle,

00:37:59.620 | or even extended too far across the 24 hour cycle,

00:38:04.080 | meaning you're eating across a 14 or a 16 hour,

00:38:06.740 | an 18 hour window that causes serious problems.

00:38:10.140 | And this has now been established

00:38:12.820 | because of the fact that it increases the expression

00:38:16.740 | of different proteins and genes in the body,

00:38:18.480 | such as TNF alpha, IL-6, IL-1.

00:38:21.020 | What are all those things?

00:38:22.260 | They are pro-inflammatory markers.

00:38:24.500 | So the reason that the liver gets sick

00:38:26.420 | when you're eating too often

00:38:28.180 | is because inflammatory markers are increased.

00:38:31.440 | These inflammatory markers are not inherently bad.

00:38:34.140 | They're there for a reason,

00:38:35.620 | but they are there in order to respond

00:38:38.060 | to certain challenges, immune challenges,

00:38:40.580 | or the ingestion of food and the breakdown of food.

00:38:42.900 | But then in an ideal circumstance,

00:38:45.900 | they are reduced in the period

00:38:48.520 | in which there's no food present in the digestive tract

00:38:51.340 | or in which there's very little food present

00:38:53.020 | in the digestive tract.

00:38:54.380 | So by eating around the clock,

00:38:55.860 | you're making yourself sicker.

00:38:57.300 | By eating at restricted periods of time each 24 hour day,

00:39:01.060 | you're actually making yourself healthier

00:39:02.900 | and you're activating certain processes

00:39:06.160 | that can positively impact both weight,

00:39:09.860 | either maintenance or loss of weight.

00:39:11.700 | We'll talk about weight gain a little later

00:39:13.340 | and positively impacting things like liver health.

00:39:16.020 | Also the expression of different things

00:39:18.420 | related to brown fat,

00:39:20.020 | the fat that increases your metabolism.

00:39:21.780 | We will return to this also a little bit later

00:39:24.180 | and blood glucose regulation.

00:39:27.260 | So the takeaway from this study,

00:39:29.460 | in fact, there are many takeaways from this study.

00:39:31.100 | It's so wonderful is that liver health,

00:39:35.380 | bile acid metabolism, energy expenditure, inflammation,

00:39:39.320 | liver metabolites, many, many aspects of our health

00:39:44.900 | are impacted by when we eat, not just what we eat.

00:39:48.280 | As we move forward and we talk about intermittent fasting

00:39:51.260 | for eight hour windows, six hour windows, 12 hour windows,

00:39:54.780 | for all sorts of different intents and purposes,

00:39:57.660 | I want to start to establish a foundational protocol

00:40:01.380 | that all of us, any of us can use

00:40:04.460 | in order to maximize your particular goals.

00:40:07.840 | There are some absolutes within this realm

00:40:10.700 | of time restricted feeding.

00:40:12.740 | Here are a couple of absolutes

00:40:14.360 | that you would want to consider.

00:40:15.740 | First of all, it pays off in the metabolic sense

00:40:20.740 | and in the health sense

00:40:22.620 | and in the weight maintenance or loss sense

00:40:25.960 | to not ingest any food in the first hour after waking

00:40:30.380 | and potentially for longer.

00:40:32.960 | So I want to repeat that.

00:40:33.920 | One of the key pillars of intermittent fasting

00:40:36.400 | is that for the first hour after you wake up

00:40:39.560 | and potentially for longer to not ingest any food, okay?

00:40:43.960 | The second major pillar that's well supported by research

00:40:47.720 | is that for the two and ideally three hours

00:40:51.360 | prior to bedtime, you also don't ingest any food

00:40:55.860 | or liquid calories for that matter.

00:40:57.580 | And we will talk about what it means to break a fast

00:41:00.740 | and whether or not certain liquids,

00:41:02.380 | even coffee and tea can break a fast, et cetera,

00:41:04.700 | in a few moments.

00:41:05.540 | But just as a foundation,

00:41:08.540 | it's very clear from the research in humans

00:41:10.940 | that not eating any food or ingesting any calories,

00:41:14.220 | liquid or otherwise,

00:41:15.540 | for the first 60 minutes after waking up each day

00:41:19.460 | and for the two to three hours prior to your bedtime,

00:41:23.840 | that's ideal for the parameters that we've discussed earlier,

00:41:27.760 | all the different things like weight and liver health

00:41:30.080 | and metabolic health and so forth.

00:41:32.280 | The two most common questions about intermittent fasting

00:41:34.900 | are when is the ideal time for the eating window?

00:41:38.040 | Is it early in the day, the middle of the day

00:41:39.560 | or late or in the day?

00:41:41.120 | And how long should that eating window be?

00:41:43.900 | Should it be eight hours?

00:41:45.180 | We already heard why the eight hour window

00:41:47.320 | was first established.

00:41:48.700 | It was because of these lab conditions

00:41:50.280 | and the conditions of the particular relationship

00:41:52.320 | of the graduate student involved,

00:41:54.020 | or should it be seven hours or six hours or 12 hours?

00:41:57.180 | Turns out that there's some general frameworks

00:41:59.920 | that we can follow in order to answer these questions.

00:42:03.020 | As we move into this portion of the discussion,

00:42:05.080 | I want to highlight a very important reference

00:42:07.940 | that just came out, literally came out last week

00:42:11.340 | in the journal, endocrinology reviews.

00:42:14.020 | And the title of this review is time restricted eating

00:42:16.960 | for the prevention and management of metabolic diseases.

00:42:20.480 | Although the data in this paper

00:42:23.160 | go well beyond metabolic diseases.

00:42:25.080 | This is a paper from Sachin Panda's lab.

00:42:27.860 | It's a very lengthy review with an enormous table

00:42:31.520 | that's beautifully organized that scripts out

00:42:35.040 | all the studies done in humans, well over a hundred studies,

00:42:39.540 | looking at time restricted feeding in athletes,

00:42:41.840 | men, women, children, diabetes, no diabetes, et cetera,

00:42:45.420 | with detailed references and description of the outcomes.

00:42:48.760 | Spent a lot of time with this review,

00:42:50.440 | even though it just came out recently

00:42:51.880 | and is a absolute goldmine resource.

00:42:55.020 | It is also the major resource for everything

00:42:56.960 | I'm about to tell you,

00:42:58.000 | if you would like to delve deeper into the material.

00:43:00.840 | So let's deal with this first question

00:43:02.940 | of when is the ideal feeding window?

00:43:05.500 | And here again, we're thinking about a schedule of eating

00:43:08.960 | that involves eating at least once every 24 hours,

00:43:12.100 | not two day or three day or every other day fast.

00:43:15.060 | So it turns out that the answer to the question,

00:43:18.600 | when is it best to eat is actually best answered

00:43:22.160 | by thinking about the other side of the coin,

00:43:24.240 | which is when is it best to fast?

00:43:27.120 | So because we are fasting during sleep,

00:43:30.640 | it's very clear that it's best to extend

00:43:33.680 | the sleep related fast either into the morning

00:43:38.240 | or to start it in the evening.

00:43:41.080 | Now this might seem kind of obvious,

00:43:42.520 | but it's actually not so obvious.

00:43:45.240 | You could place that feeding window early in the day,

00:43:48.460 | middle of the day or late in the day.

00:43:50.600 | Let's think about what happens when we sleep.

00:43:53.000 | When we sleep, our body undergoes a number

00:43:56.140 | of different processes in the brain and body

00:43:58.680 | in order to recover the cells and tissues.

00:44:01.680 | Many of you have probably heard of autophagy,

00:44:03.600 | which is essentially cleaning up a gobbling up

00:44:06.560 | of dead cells and cells that are injured or sick.

00:44:09.480 | And this is a natural process that occurs

00:44:11.680 | and it occurs mainly during sleep,

00:44:13.480 | although not only during sleep.

00:44:17.120 | Fasting of any kind does tend to enhance autophagy.

00:44:21.380 | It is not the only way to create autophagic conditions.

00:44:26.380 | Autophagic conditions can be created simply

00:44:28.740 | by following a sub caloric diet.

00:44:30.660 | And there are other things that one can do

00:44:32.540 | in order to trigger autophagy,

00:44:34.800 | but fasting does trigger autophagy.

00:44:36.800 | So when we're asleep, the bad cells are getting gobbled up

00:44:39.640 | and eaten and the good cells also are undergoing

00:44:43.880 | certain repair mechanisms, mainly related to,

00:44:46.420 | or at least governed by those circadian genes

00:44:48.840 | that we talked about earlier, those clock genes.

00:44:51.480 | So you're already fasting when you're asleep

00:44:54.640 | and how deep you are into that fast depends

00:44:57.960 | on how long it was since your last meal.

00:45:01.000 | So if you fast early in the day

00:45:04.220 | and you've been asleep for five, six, seven, eight hours,

00:45:08.380 | I would hope somewhere between six and eight hours

00:45:10.400 | for most people is going to be beneficial.

00:45:12.840 | When you wake up, I mentioned earlier

00:45:15.560 | that you don't want to eat

00:45:16.580 | for at least the first 60 minutes after waking,

00:45:19.200 | but were you to extend that fasting to say 9 AM, 10 AM,

00:45:24.200 | 11 AM, or even 12 noon or later,

00:45:27.220 | you are taking advantage of the deep fast

00:45:29.740 | that you were in during sleep

00:45:31.920 | and certainly toward the end of sleep.

00:45:33.540 | Now, why do I say deep fast?

00:45:34.920 | Well, because when we eat the clearance of that food

00:45:39.920 | from our gut and the processes in our cells and organs

00:45:44.420 | that are related to digestion

00:45:46.300 | and the utilization of that food takes

00:45:49.400 | about five to six hours.

00:45:51.460 | So if you eat a meal and that meal lasts 10 minutes,

00:45:55.680 | 20 minutes, or 30 minutes, or even an hour,

00:45:57.900 | and then you stop eating, you've stopped eating,

00:46:00.520 | but you are not fasting at that point.

00:46:03.200 | You can say you're fasting

00:46:04.240 | 'cause you're no longer putting food

00:46:05.640 | into your digestive tract,

00:46:07.480 | but you are not in a fasted state.

00:46:09.460 | You are not under conditions of fasting.

00:46:12.400 | Later, I'll talk about things that you can do

00:46:13.840 | to accelerate the transition into fasting.

00:46:16.380 | So one thing is certain that you want your eating window

00:46:20.120 | to be tacked or attached to your sleep-based fasting

00:46:25.120 | in a way that makes it easier for you

00:46:28.260 | to get into the fasted state for a period of time.

00:46:31.300 | So we can view that point from the perspective of best,

00:46:36.300 | better, and worst, okay?

00:46:39.320 | So if you are like most people and you sleep at night,

00:46:42.440 | you're waking up somewhere around 6.37 AM

00:46:44.720 | or maybe even 8 AM,

00:46:45.920 | let's say you were to push your fasting window out

00:46:49.160 | such that you started eating at noon

00:46:52.640 | and then you stopped eating at 6 PM.

00:46:56.560 | Well, then you're not eating from 6 PM

00:47:01.000 | until let's say your bedtime is 10 PM,

00:47:03.000 | but from 6 PM to 10 PM,

00:47:04.560 | your body is not yet in a fasted state

00:47:07.120 | because you just ate.

00:47:09.120 | However, you're starting to taper into a fasted state

00:47:12.440 | before sleep and then all through sleep

00:47:15.000 | and until the next morning and late morning,

00:47:17.740 | you are actually in a fasted state.

00:47:20.120 | Now, most people find it very hard to only eat

00:47:22.680 | in the middle of the day.

00:47:24.040 | So while that's best,

00:47:25.360 | it's ideal for sake of the fasting related improvements

00:47:28.800 | in health, it is not ideal and it's not very applicable

00:47:33.800 | to most work and family and social situations.

00:47:37.240 | Most people eat breakfast with others

00:47:39.460 | and or eat dinner with others.

00:47:41.880 | Some people eat lunch with others,

00:47:43.480 | but in general, it's hard to restrict your feeding window

00:47:46.260 | to just the absolute middle of the day.

00:47:48.340 | But from a purely health perspective in a very objective way,

00:47:51.780 | that would be the ideal situation.

00:47:54.040 | Let's imagine a different pattern of eating

00:47:56.260 | where the feeding window starts in the afternoon,

00:47:59.620 | starts around two or even 3 PM.

00:48:02.100 | Some people don't have much trouble

00:48:03.520 | or they can train themselves to get their feeding window out

00:48:06.860 | to two or 3 PM.

00:48:08.640 | And then they will eat until 10 or 11 PM, right?

00:48:11.560 | If you do the math,

00:48:12.400 | you realize that that feeding window is still pretty short.

00:48:14.680 | It's still constitutes what we would call

00:48:16.640 | intermittent fasting or time restricted feeding.

00:48:19.320 | But assuming that they go to bed around 11 PM or midnight,

00:48:23.200 | they are not actually fasted in sleep

00:48:26.960 | because for the first six hours or so of sleep,

00:48:30.360 | maybe five, but probably more like six hours of sleep,

00:48:32.860 | they're still digesting the food

00:48:34.180 | that they consumed late in the night.

00:48:36.720 | It does appear beneficial to grab a hold of

00:48:41.320 | that sleep related fast,

00:48:43.980 | meaning you don't want your feeding window

00:48:47.520 | to be too close to bedtime.

00:48:48.700 | And that's why we came up with this

00:48:50.160 | kind of foundational pillar

00:48:52.160 | that I discussed with Sachin earlier,

00:48:53.880 | which is at least no eating for the first hour after waking,

00:48:57.440 | but also no eating within two to three hours prior to bed.

00:49:01.680 | And because we all need to sleep

00:49:02.840 | and sleep is exceedingly important

00:49:04.840 | for our health of all kinds, you want to prioritize sleep,

00:49:08.740 | but because we also have to eat,

00:49:10.520 | then you start to think about this and maybe it's not so good

00:49:13.460 | to push that feeding window too late in the day,

00:49:16.240 | because when you go to sleep,

00:49:17.780 | you're not actually capitalizing

00:49:19.320 | on the sleep related fasting.

00:49:21.220 | Now it's not just the case

00:49:22.840 | that it's easiest to fast while in sleep.

00:49:24.720 | Although that's true because when we're asleep,

00:49:26.560 | typically we're not hungry or looking for food

00:49:28.940 | or foraging for food or wanting food

00:49:30.560 | or trying to resist food.

00:49:31.940 | We're just sleeping.

00:49:33.980 | There is something special

00:49:35.440 | about the fasting that occurs during sleep,

00:49:37.800 | because it's associated with a number of processes

00:49:40.820 | that relate to the so-called glymphatic system.

00:49:43.400 | The movement of lymph-like fluids

00:49:45.880 | and other fluids through the brain

00:49:47.320 | are kind of sweeping out garbage disposal, if you will,

00:49:50.580 | a clearing out of the metabolic debris

00:49:53.020 | and some of the autophagy that's associated

00:49:55.240 | with bad processes in the brain.

00:49:58.640 | So we could do a whole episode on this,

00:50:00.300 | but essentially during sleep

00:50:01.720 | and in particular during fasted states of sleep,

00:50:05.240 | we are undergoing a number of automatic cellular processes

00:50:09.660 | that clear out debris from our brain,

00:50:11.900 | enhance cognition, or at least offset dementia.

00:50:14.680 | This is now well-established,

00:50:16.280 | as well as a number of the same processes

00:50:17.900 | occurring in the organs of our body.

00:50:19.860 | So what we're starting to see here

00:50:22.160 | is that there are a number of constraints

00:50:23.600 | on when you can eat.

00:50:24.940 | Now I would be remiss if I didn't acknowledge

00:50:27.560 | the social constraints and the real life constraints.

00:50:30.120 | Some of us, because we want to eat with our family

00:50:32.720 | and because our family or our significant others

00:50:35.700 | eat around eight or 9 p.m.

00:50:37.120 | and that's the only time we're together,

00:50:38.320 | you have to eat late in the day.

00:50:40.600 | And that's certainly not a sin.

00:50:41.880 | I'm not saying that's good or bad.

00:50:44.000 | Here we're trying to establish, if you recall,

00:50:45.880 | best, better, and worst.

00:50:48.040 | So from both a practical and a health perspective

00:50:52.040 | and a purely objective view

00:50:53.800 | of how intermittent fasting works and can benefit us,

00:50:58.200 | starting to eat each day,

00:51:00.400 | somewhere around 10 a.m. or around noon,

00:51:05.040 | and then allowing a feeding window

00:51:07.240 | that goes until six or maybe 8 p.m.,

00:51:11.560 | that seems to me, at least based on the data

00:51:14.780 | and what I understand about typical cultures

00:51:17.080 | where people eat in the daytime and in the evening,

00:51:20.360 | that seems to me like the kind of schedule

00:51:24.180 | that will allow you to get the most

00:51:26.240 | out of intermittent fasting, time-restricted feeding,

00:51:28.880 | but does not set you up to be really out of sync

00:51:32.940 | with the social rhythms in most cultures.

00:51:35.460 | If you think about it from the perspective of, say,

00:51:38.800 | a noon to eight feeding window,

00:51:42.240 | what you'll find is that you're able to eat lunch

00:51:44.440 | with others, if you like, or by yourself,

00:51:47.480 | you will be able to eat dinner at a reasonable hour,

00:51:50.400 | at least in most countries, in most cultures,

00:51:52.200 | eating dinner somewhere between 6.30 and 7 p.m.

00:51:56.160 | is typical.

00:51:57.900 | When you say a feeding window that goes until eight,

00:52:01.340 | that doesn't mean sitting down to dinner at eight.

00:52:03.920 | That means your last bite of food

00:52:05.520 | or ingestion of any liquid calories was at 8 p.m.

00:52:08.660 | Assuming that you go to bed somewhere between 10 p.m.

00:52:12.360 | and 1 a.m., that allows this tapering off

00:52:14.920 | or this transition from feeding to a fasted state

00:52:18.400 | and still allows you to capitalize

00:52:20.480 | on the special period of fasting

00:52:22.520 | that is sleep-related fasting.

00:52:24.880 | And again, I want to emphasize that the fasting

00:52:26.700 | that occurs during sleep is vital

00:52:28.480 | and eating too close to sleep will disrupt

00:52:31.200 | that fasting-related sleep.

00:52:33.600 | Now, there are a number of caveats

00:52:35.500 | and details related to this,

00:52:37.440 | and there's an important caveat and detail related to people

00:52:41.520 | that are specifically interested in increasing

00:52:44.900 | or maintaining muscle mass.

00:52:46.880 | So first let's talk about food volume and food type

00:52:51.680 | and how that relates to whether or not you quickly

00:52:55.680 | or slowly enter a fasted state.

00:52:58.200 | Because clearly when we talk about a feeding window,

00:53:01.760 | that feeding window could include any number

00:53:03.440 | of different foods.

00:53:04.280 | It could involve cake and ice cream, pizza, hamburgers,

00:53:07.180 | plants, fruit, whatever it is,

00:53:09.720 | or it could involve just fats or just proteins, et cetera.

00:53:14.000 | There are at least three factors that are going to govern

00:53:16.880 | how quickly you transition from ingesting food

00:53:21.880 | to a fasted state.

00:53:22.720 | Remember, as you ingest your last bite or sip of calories,

00:53:26.920 | that's not when the fast begins.

00:53:28.440 | That might be when the fasting begins on your watch

00:53:31.280 | or on one of these apps that I'll refer to later,

00:53:33.200 | which can help you track your fasting and eating windows.

00:53:35.700 | But that's not when it actually begins

00:53:37.920 | because your body is still seeing food.

00:53:40.180 | You're actually carrying around food inside of you.

00:53:43.100 | Even though you're not putting it into your mouth,

00:53:45.160 | you're still eating in some sense.

00:53:47.960 | So it should be somewhat obvious that very large meals

00:53:51.240 | are going to take longer to digest than very small meals.

00:53:53.740 | So that will impact how slowly or quickly you migrate

00:53:58.040 | from a fed state to a fasted state.

00:54:00.880 | There's no way I can spell out what exact volume of food

00:54:05.240 | you should ingest based on the size of your stomach

00:54:07.240 | and et cetera.

00:54:08.520 | But you're all familiar with being extremely full,

00:54:11.520 | very full, comfortably full, somewhat full,

00:54:15.120 | or not feeling full and feeling hungry.

00:54:17.880 | So learning to gauge food volume is important.

00:54:21.640 | Also foods that include some fats or a lot of fats

00:54:25.840 | will tend to slow gastric emptying time.

00:54:28.800 | And depending on the kind of fats,

00:54:31.560 | it could mean that a given meal is digested

00:54:33.760 | within three hours versus five hours.

00:54:35.660 | So more fats might be a large meal with a lot of fats

00:54:38.440 | has been going to take five or six hours.

00:54:39.920 | A smaller meal with less fat is going to be digested

00:54:42.080 | more quickly.

00:54:43.440 | Consuming calories in liquid form is going to mean

00:54:45.880 | that gastric emptying time is going to be faster.

00:54:48.500 | And then of course,

00:54:49.340 | there's the glucose and the insulin aspect to it,

00:54:51.960 | which is that foods that lead to big,

00:54:54.280 | steep rises in glucose, like pure sugars,

00:54:56.580 | then your glucose will drop.

00:54:59.000 | However, if they're combined with fats,

00:55:00.840 | then it tends to be a more gradual rise in glucose

00:55:02.880 | and it's more sustained, et cetera.

00:55:04.520 | Fibrous foods will also create a more long lasting,

00:55:07.480 | sustained release in glucose.

00:55:09.420 | The important thing here is to establish a feeding window

00:55:14.420 | that you can comfortably manage, okay?

00:55:17.300 | Meaning that on average,

00:55:18.800 | you can obey a six hour feeding window

00:55:21.840 | or an eight hour feeding window or a 10 hour feeding window.

00:55:24.780 | And then to place that feeding window in a social

00:55:28.540 | and life context that you can manage on a regular basis.

00:55:32.440 | Now, there are two key points that have been gleaned

00:55:35.040 | from the scientific data about this feeding window

00:55:37.900 | and when to place it.

00:55:39.320 | And this is based on a really important experiment

00:55:42.140 | that Sachin and his colleagues have been doing.

00:55:44.080 | There's a website that they have,

00:55:45.660 | a zero cost website called My Circadian Clock.

00:55:48.300 | You can go to this website free of cost.

00:55:50.820 | There are a number of important resources there,

00:55:52.660 | but what they've done is they've examined

00:55:55.280 | the feeding behavior of thousands of people.

00:55:58.780 | People will take a picture of the food they're about to eat

00:56:01.160 | and it enters into their account,

00:56:03.040 | maybe your account if you create one on My Circadian Clock.

00:56:05.920 | And they do this over many days or weeks.

00:56:08.700 | What's great about this is it establishes

00:56:11.800 | what's essentially called a phytogram,

00:56:14.080 | a time in which people ate.

00:56:16.500 | And a number of important findings have emerged

00:56:19.400 | from these phytograms across large populations

00:56:22.540 | of people in different time zones

00:56:24.060 | with different schedules, et cetera.

00:56:25.460 | First of all, almost everybody underestimates

00:56:29.900 | their feeding window, meaning people who think

00:56:32.600 | that they are on an eight hour feeding window

00:56:35.660 | or six hour feeding window, when their data are analyzed,

00:56:40.660 | it almost is always the case that they're actually

00:56:43.020 | on a feeding window that's one or even two hours longer

00:56:45.940 | than they think.

00:56:46.860 | You think, well, how could that possibly be?

00:56:48.180 | If people are taking their first bite at noon

00:56:50.380 | and they're taking their last bite at 8 p.m.,

00:56:53.380 | well, that must mean that they are on that feeding window

00:56:57.020 | of eight hours.

00:56:58.360 | And it turns out that people cheat,

00:57:01.620 | but they don't cheat in any kind of obvious way.

00:57:03.460 | They might have, you know, a glass of wine after dinner,

00:57:06.420 | or they'll have a cup of tea and a little bite of a cookie.

00:57:08.660 | And so when people are honest, and they are honest,

00:57:10.780 | in most cases, for this experiment,

00:57:14.280 | what you find is that most people's eating window

00:57:16.020 | is actually quite a bit longer.

00:57:17.160 | So in discussing this with Satchin

00:57:18.660 | and reviewing the literature, it's clear that if you'd like

00:57:21.940 | to be on a 10 hour feeding window,

00:57:25.980 | that you should probably select an eight hour feeding window

00:57:29.540 | because there's always a little bit of a taper

00:57:32.420 | on either side of that eating window.

00:57:34.180 | Very few people are extremely strict

00:57:36.640 | about these eating windows.

00:57:37.560 | It's just hard to do in the context of life events

00:57:39.800 | and social gatherings and family and so forth.

00:57:43.300 | Okay, so as we build forward your ideal fasting/

00:57:48.180 | time restricted feeding schedule,

00:57:49.820 | we now have several different rules that we can list out.

00:57:52.980 | First, at least no food for the first hour after waking up,

00:57:57.060 | at least one hour.

00:57:59.260 | Two, no food intake for two,

00:58:03.300 | and ideally three hours prior to your bedtime.

00:58:06.200 | Three, if you want to select an eight hour feeding window,

00:58:12.340 | then you should probably focus on a six

00:58:15.100 | or seven hour feeding window because in reality,

00:58:17.540 | your feeding window is going to be longer.

00:58:19.980 | Reality meaning real life constraints.

00:58:22.060 | And if you'd like to be on a 10 hour feeding window,

00:58:25.740 | you should probably select an eight

00:58:27.180 | or a nine hour feeding window

00:58:28.740 | because the way it plays out is that people

00:58:30.420 | almost always eat outside of their eating window somewhat.

00:58:34.620 | The other nice thing about selecting

00:58:36.380 | a slightly shorter eating window than is comfortable for you

00:58:40.420 | is that it takes into account that as you take

00:58:44.300 | your last bite or your last sip of calories,

00:58:46.520 | there's this time or taper before which you are actually

00:58:50.460 | in a fasted state.

00:58:52.120 | And because you're eating different things

00:58:53.780 | on different days, presumably,

00:58:55.500 | some foods leave your gut more quickly,

00:58:57.560 | some things spike your insulin

00:58:58.900 | and your glucose more than others.

00:59:01.180 | Sometimes you eat more fat, sometimes less fat.

00:59:03.540 | This allows you to fall well within the margins

00:59:07.980 | of the benefits of time restricted feeding

00:59:10.220 | that have been demonstrated in humans,

00:59:11.900 | which generally involve an eight hour window or so.

00:59:16.660 | So I think this eight hour window or six hour window

00:59:19.840 | is a good thing to shoot for, for most people.

00:59:22.720 | Some people, and we will discuss the exceptions,

00:59:24.500 | but some people truly are exceptions to this.

00:59:26.980 | They just require more food.

00:59:29.400 | And along those lines,

00:59:30.680 | I just now briefly want to touch on some of the studies

00:59:32.760 | that have looked at using a very short feeding window

00:59:35.100 | of about four hours.

00:59:36.780 | Nowadays, a number of people are doing

00:59:38.400 | the so-called one meal per day or are restricting

00:59:41.340 | their feeding window to just four hours or six hours.

00:59:45.020 | And that turns out to be an interesting strategy.

00:59:48.320 | And the data around it actually are a little bit surprising.

00:59:51.320 | One surprising thing to leap out of this massive literature

00:59:54.720 | review on time restricted feeding in humans is that

00:59:58.660 | relatively short feeding windows of say four to six hours

01:00:03.140 | do produce a number of positive health effects,

01:00:06.100 | things like increased insulin sensitivity,

01:00:08.300 | which we know is good.

01:00:09.540 | Remember type two diabetes is a reduction

01:00:11.660 | in insulin sensitivity,

01:00:13.660 | improvements in beta cell function and the pancreas,

01:00:16.700 | decreased blood pressure, decreased oxidative stress,

01:00:19.780 | decreases in things like evening appetite.

01:00:24.100 | So positive health effects and psychological effects

01:00:27.260 | in general.

01:00:28.540 | However, they either produce no change in body weight,

01:00:33.420 | or they tend to produce even increases in body weight.

01:00:37.680 | Now, of course, there's variation between individuals

01:00:40.240 | and between studies, but this is somewhat surprising.

01:00:43.680 | So the eight hour feeding window seems to be very beneficial

01:00:46.800 | across almost all the parameters that we've discussed,

01:00:49.940 | inflammation, weight loss, fat loss, et cetera,

01:00:53.440 | and adherence, I should mention people's ability

01:00:55.540 | to stick to the diet seems quite good

01:00:58.060 | on this eight hour feeding windows.

01:01:00.000 | But when people try and undergo very short feeding windows

01:01:03.140 | of four to six hours,

01:01:04.860 | it seems that they are overeating in that four to six hours,

01:01:07.680 | at least overeating with respect to their metabolic needs.

01:01:11.860 | Now, the contrast to this is the so-called

01:01:16.400 | one meal per day schedule.

01:01:18.360 | Very few studies on one meal per day.

01:01:20.820 | One meal per day, unless it's a very, very long meal

01:01:23.120 | sort of feast, typically would not last four to six hours,

01:01:26.720 | because it sort of depends on how you define a meal.

01:01:28.820 | But when you look at the very few,

01:01:31.280 | I should emphasize again,

01:01:32.120 | very few studies on one meal per day,

01:01:34.220 | people typically maintain or lose weight

01:01:36.740 | on the one meal per day schedule.

01:01:38.560 | So what we can say is that the seven to nine hour

01:01:41.400 | feeding window produces all of the major health benefits

01:01:45.740 | of time restricted feeding,

01:01:47.880 | as well as being pretty straightforward

01:01:49.780 | for most people to adhere to on a regular basis

01:01:52.960 | and on a regular basis turns out to be very important.

01:01:55.120 | I'll get back to that point in a moment.

01:01:56.600 | Whereas the four to six hour eating window

01:01:58.900 | doesn't seem to serve people as well as say

01:02:01.280 | a seven or eight hour eating window,

01:02:03.020 | simply because people are overeating

01:02:04.720 | during that eating window and the one meal per day,

01:02:07.640 | while perhaps ideal for certain people's schedules

01:02:11.600 | may actually cause people to under eat.

01:02:13.360 | And in some cases that might be what people want.

01:02:15.360 | They actually want to under eat.

01:02:17.000 | But when we start thinking about performance

01:02:19.800 | in work and in sport, and when we start considering

01:02:24.400 | hormone health and hormone production, fertility,

01:02:27.840 | that's when we can really start to look at the

01:02:30.480 | seven to nine hour feeding window

01:02:33.400 | versus the four to six hour feeding window

01:02:35.260 | versus the one meal per day type feeding window

01:02:38.400 | with some different objectivity,

01:02:40.600 | we can start to look at it through a different lens

01:02:42.400 | because it turns out that when you place the feeding window

01:02:46.540 | and how long that feeding window is actually will impact

01:02:50.600 | a number of other things in particular hormones

01:02:53.160 | that can be very important for a number of things

01:02:55.680 | related to sex and reproduction,

01:02:58.040 | can be related to performance at work,

01:03:01.360 | performance in athleticism.

01:03:03.720 | And there are excellent studies on this.

01:03:05.660 | So let's explore those now.

01:03:07.920 | So let's talk about some conditions where

01:03:09.980 | having the feeding window early in the day

01:03:12.160 | would actually be very beneficial.

01:03:14.420 | There was a study that was published recently in cell

01:03:16.880 | reports, again, cell press journal, excellent journal,

01:03:19.480 | peer reviewed, very stringent from IOMA at all.

01:03:24.400 | So this is A-O-Y-A-M-A at all.

01:03:28.040 | This was published just recently in July, 2021

01:03:31.740 | that looked at the distribution of protein intake

01:03:36.740 | in different meals delivered either early in the day

01:03:40.860 | or later in the day.

01:03:42.080 | And I'm summarizing here quite a lot,

01:03:43.620 | but I should mention that this study was performed

01:03:46.420 | in both mice and humans, same paper, mice and humans,

01:03:50.200 | and involved hypertrophy training,

01:03:53.040 | essentially increasing the weight bearing of given limbs

01:03:57.920 | to try and induce hypertrophy,

01:03:59.840 | which is the growth of muscle tissue.

01:04:02.240 | It does appear that muscle tissue is better able

01:04:08.200 | to undergo hypertrophy by virtue of the fact that

01:04:12.840 | there's better or enhanced protein synthesis

01:04:15.760 | early in the day, because of the expression

01:04:18.000 | of one of these particular clock genes called BMAL, B-M-A-L.

01:04:21.900 | BMAL regulates a number of different protein synthesis

01:04:26.400 | pathways within muscle cells,

01:04:28.840 | such that eating protein early in the day

01:04:32.280 | supports muscle tissue maintenance and or growth.

01:04:36.200 | And in the study, they also looked at the effects

01:04:38.480 | of supplementing so-called BCAAs, branch chain amino acids,

01:04:41.860 | which is popular in bodybuilding circles

01:04:44.860 | and in strength training circles.

01:04:46.380 | And BCAAs are essential components

01:04:48.900 | of a number of different foods,

01:04:51.740 | but can also be supplemented.

01:04:53.800 | The takeaway of the study is pretty straightforward.

01:04:56.100 | However, the takeaway is if your main interest

01:04:58.960 | is maintaining and or building muscle,

01:05:02.120 | then it can be beneficial to ingest protein early in the day.

01:05:05.620 | You would still want to obey this,

01:05:07.680 | what we're calling a kind of foundational rule

01:05:11.540 | of not eating any food for the first hour post waking,

01:05:15.680 | or at least the first hour post waking.

01:05:17.560 | And the cutoff for when you would want to eat protein

01:05:20.480 | would be sometime before 10 AM.

01:05:23.080 | And there I'm averaging across a number

01:05:24.880 | of different situations.

01:05:27.280 | But in general, this BMAL expression is such that,

01:05:30.800 | let's say you wake up at 7 AM,

01:05:32.460 | your main interest is in hypertrophy

01:05:35.500 | or maintenance of muscle.

01:05:36.760 | Then you would want to ingest some protein

01:05:38.600 | sometime before 10 AM.

01:05:39.960 | But obviously if you're interested in getting

01:05:42.420 | the health effects of intermittent fasting,

01:05:44.400 | that you wouldn't ingest any food

01:05:46.960 | for at least the first 60 minutes upon waking.

01:05:49.320 | Now it's not as if at 1001 AM,

01:05:52.880 | a gate slammed shut and you can't generate hypertrophy.

01:05:55.600 | Of course, that's not the case.

01:05:57.760 | However, it's very interesting that it doesn't matter

01:06:00.120 | when the resistance training,

01:06:01.640 | the load bearing exercise occurs in the 24 hour cycle.

01:06:06.000 | So whether or not, in other words,

01:06:07.680 | people are training early in the day

01:06:09.260 | or they're training late in the day,

01:06:11.060 | it still appears that ingesting protein early in the day

01:06:14.820 | favors hypertrophy or that one is better,

01:06:18.500 | or I should say more easily able to access hypertrophy

01:06:21.980 | by way of these clock regulated protein synthesis mechanisms

01:06:26.220 | by ingesting protein early in the day.

01:06:28.980 | In no way, shape or form does this study say

01:06:31.420 | that ingesting protein later in the day

01:06:33.200 | is somehow bad for you.

01:06:34.360 | It just emphasizes the positive effects

01:06:36.820 | of ingesting protein early in the day

01:06:39.060 | for sake of muscle maintenance and or hypertrophy.

01:06:42.920 | So if you're somebody who's mainly concerned

01:06:44.680 | with muscle maintenance and hypertrophy,

01:06:46.780 | then it may make sense to move that feeding window

01:06:50.520 | earlier in the day.

01:06:51.840 | And certainly there are people out there

01:06:53.520 | who are interested in muscle maintenance and hypertrophy

01:06:56.280 | who aren't doing intermittent fasting at all.

01:06:58.020 | And that's also perfectly fine,

01:06:59.240 | but this just so happens to be an episode

01:07:01.020 | about intermittent fasting and time restricted feeding.

01:07:04.540 | There are of course modes of eating

01:07:06.320 | where one eats small meals spread throughout the day

01:07:09.080 | or weights meals differently such that meals early in the day

01:07:12.520 | are larger than later in the day or vice versa.

01:07:14.920 | There are in a near infinite number of ways to organize this.

01:07:18.140 | But if you are somebody who's interested in deriving

01:07:21.100 | the many clearly established health effects

01:07:23.960 | of time restricted feeding,

01:07:25.160 | and you are somebody who would like to maintain

01:07:28.020 | or build muscle,

01:07:29.920 | then ingesting proteins in the early part of the day

01:07:35.040 | would be important to you,

01:07:36.580 | at least on the basis of these results.

01:07:38.840 | And therefore that eight hour window

01:07:41.400 | that we've established as more or less ideal

01:07:44.240 | shifted to the later part of the day

01:07:46.360 | might not be as beneficial for you.

01:07:48.660 | Now, I can just personally say that for me,

01:07:51.720 | when I wake up in the morning,

01:07:52.760 | it's very easy for me to not eat

01:07:54.800 | until noon or one or 2 p.m.

01:07:57.560 | Eating early in the day is actually somewhat of a challenge.

01:08:00.920 | I discussed this point with Sachin

01:08:02.720 | because we were talking about

01:08:04.200 | how is it that one can move their feeding window

01:08:07.220 | or place themselves onto a different schedule

01:08:09.920 | of intermittent fasting.

01:08:11.480 | And it's very clear that one needs to provide

01:08:14.000 | a transition period in order for that to happen.

01:08:16.700 | You should allow yourself a transition period

01:08:18.720 | of anywhere from one week to 10 days

01:08:21.820 | in which you shift your feeding window

01:08:23.720 | by about an hour each day or so.

01:08:26.800 | And then once you establish a feeding window

01:08:29.340 | that feels comfortable for you

01:08:30.880 | and that you think you can maintain over time,

01:08:33.180 | that you simply maintain that feeding schedule

01:08:35.680 | for at least 30 days,

01:08:37.920 | but ideally you would do that indefinitely.

01:08:40.280 | Now, this turns out to be important

01:08:41.840 | based on data that they've gleaned

01:08:43.600 | from this my circadian clock,

01:08:46.280 | massive experiment that they've been doing

01:08:47.760 | where people are entering the times

01:08:48.920 | that they're feeding and eating.

01:08:50.820 | Excuse me, anytime we talk about mice,

01:08:53.040 | I always think about feeding

01:08:54.100 | because I come from a background

01:08:55.780 | and my lab works on both laboratory mice and on humans.

01:08:58.420 | Anytime I think about humans, I think about eating,

01:09:00.240 | but of course they are the same thing.

01:09:02.840 | The interesting thing to emerge

01:09:05.000 | from that very large data set in humans

01:09:07.720 | is that when people log their feeding times,

01:09:10.780 | as I mentioned before,

01:09:11.700 | oftentimes they think they're eating in an eight hour window,

01:09:15.000 | but they are actually eating in a much broader window.

01:09:18.280 | However, even for people that are very good

01:09:21.080 | about restricting their feeding

01:09:22.940 | to a four or six or eight hour window,

01:09:25.120 | if they're very strict about the start and stop times

01:09:27.340 | when they ingest calories,

01:09:29.760 | one of the findings that's really been important to note

01:09:32.580 | is that almost every individual has a lot of drift

01:09:36.980 | in when that eating window resides in their 24 hour period.

01:09:41.180 | In particular on the weekends,

01:09:43.260 | people are either extending or shifting their feeding window

01:09:48.140 | in a way that makes it seem that they've traveled

01:09:50.580 | to another time zone

01:09:51.740 | and are eating according to another time zone.

01:09:53.940 | And this is extremely important.

01:09:57.360 | As I mentioned earlier, based on the 2012 study

01:10:01.540 | from Sachin's lab,

01:10:02.900 | we're eating at a particular phase of each 24 hour cycle

01:10:07.500 | can help enhance the expression of these clock genes.

01:10:10.360 | If you are eating within a very strict

01:10:15.540 | or semi-strict feeding window,

01:10:17.180 | but that feeding window is migrating around from day to day

01:10:20.220 | or five days a week,

01:10:21.260 | you're really organized about when that falls,

01:10:23.940 | let's say for sake of example, from noon to 8 PM,

01:10:27.140 | noon to 8 PM, Monday, noon to 8 PM, Tuesday, Wednesday,

01:10:30.680 | noon to 8 PM, Thursday, and so forth.

01:10:32.480 | But then on a Saturday, it's becoming 11 AM

01:10:36.360 | and you're ending it early,

01:10:38.900 | or perhaps you're starting early in the day on Sunday,

01:10:43.320 | you're having brunch that starts at 930 or 10,

01:10:45.680 | and then it's extending out still just eight hours,

01:10:48.240 | but it's shifting around.

01:10:49.840 | That can cause disruptions

01:10:51.820 | in these circadian clock mechanisms

01:10:53.880 | that cause disruptions in the downstream effects of eating

01:10:58.680 | that are taking at least two to three days to recover from.

01:11:03.320 | So obviously we don't want to be overly neurotic

01:11:06.160 | about this stuff,

01:11:07.000 | but because this is an episode about the science

01:11:08.600 | of intermittent fasting and time restricted feeding,

01:11:11.760 | as important as how long your feeding window is,

01:11:16.520 | is where that feeding window resides in each 24 hour cycle.

01:11:21.020 | And perhaps even more important than that

01:11:23.220 | is that it be fairly regular

01:11:25.180 | where that feeding window resides,

01:11:27.060 | because even if you have a very short feeding window,

01:11:29.060 | if it's drifting around from day to day,

01:11:31.940 | that actually offsets a number

01:11:33.760 | of the positive health effects of intermittent fasting.

01:11:36.880 | So to really just underscore the way

01:11:38.360 | that these different pieces

01:11:39.920 | of the biological puzzle fit together,

01:11:41.980 | if you are very strict or semi-strict

01:11:45.280 | about your eight hour feeding window,

01:11:46.660 | but on the weekends,

01:11:47.500 | that eight hour feeding window is falling later

01:11:50.580 | than it normally would during the middle of the week,

01:11:53.120 | it is as if you are going to bed later,

01:11:55.800 | even if you're going to bed at the same time,

01:11:58.040 | at least from the perspective of metabolic health,

01:12:00.080 | because of the way that eating impacts these clock genes

01:12:02.900 | and impacts, or I should say,

01:12:05.520 | subtracts the sleep-related fasting

01:12:08.820 | that you would normally experience

01:12:10.400 | if you were to finish eating

01:12:12.720 | a couple hours before bedtime.

01:12:14.460 | So again, we don't want to create any overly obsessive

01:12:17.620 | or neurotic focus on this.

01:12:19.560 | I think that most all people could benefit

01:12:21.840 | from a time-restricted feeding schedule,

01:12:24.260 | but they should really think hard

01:12:25.360 | about what they can stick to on a regular basis

01:12:28.040 | and understand that they tend to underestimate

01:12:30.960 | the feeding window that they actually are partaking in,

01:12:34.240 | and that they should place that feeding window

01:12:36.840 | in a portion of the 24 hour cycle

01:12:39.600 | that they can be consistent on most days.

01:12:42.920 | And I want to emphasize most,

01:12:44.280 | again, because we are not laboratory mice.

01:12:46.580 | We don't have a graduate student

01:12:47.720 | coming in for eight hours a day

01:12:48.960 | because that's what their significant other

01:12:50.320 | will allow them to do.

01:12:51.160 | And then removing the food from our jowls

01:12:52.900 | and from our cages.

01:12:54.160 | We have access to food pretty much 24 hours a day.

01:12:56.860 | Along those lines, however,

01:12:59.860 | there are things that we can all do

01:13:02.660 | that will allow us to offset some of the drift,

01:13:07.320 | if you will, that we experience

01:13:09.200 | or that we induce in terms of

01:13:11.080 | when our feeding window occurs

01:13:12.560 | or that the feeding window might push out a little later

01:13:15.780 | and then therefore start a little later the next day.

01:13:18.500 | There are things that we can do

01:13:19.340 | and there are things that we can take.

01:13:20.560 | And so I'd like to discuss those briefly.

01:13:22.600 | So throughout this episode,

01:13:24.340 | I've more or less been alluding to the fact

01:13:27.360 | that when you eat,

01:13:29.240 | there's some period of time afterwards

01:13:30.760 | in which you're actually still eating,

01:13:32.760 | at least from the perspective of metabolism,

01:13:34.740 | because glucose is up, insulin is up,

01:13:37.520 | and you're undergoing different metabolic

01:13:40.040 | and digestive processes that don't really speak to you

01:13:43.880 | being in a fasted state, right?

01:13:46.120 | It's not just about when you take your last bite

01:13:48.460 | or your last sip.

01:13:50.400 | However, there are things that we can do

01:13:52.960 | to accelerate the transition from a fed state

01:13:56.800 | to a fasted state.

01:14:00.360 | And so I'd like to discuss what those are.

01:14:02.160 | And I want to emphasize that the term fed state

01:14:05.560 | is probably a better way to think about it

01:14:08.080 | than eating or not eating,

01:14:09.920 | because we think of eating as the verb.

01:14:11.700 | We're eating, we're eating.

01:14:12.560 | Okay, we're done eating, I'm fasting now,

01:14:14.440 | but you're not actually fasting because you are fed.

01:14:18.120 | So we should really think about fed and unfed states

01:14:21.160 | because from a cellular processes perspective

01:14:23.440 | and from a health perspective,

01:14:24.920 | that's actually what your body and your system

01:14:27.400 | are paying attention to.

01:14:28.760 | And by now with everything that we've laid out,

01:14:31.320 | I think that should be intuitive to understand.

01:14:34.440 | So there's a fun and exciting concept related to this,

01:14:36.880 | which is glucose clearing.

01:14:38.460 | You may have heard the old adage

01:14:40.800 | that if you take a 20 or 30 minute walk after dinner,

01:14:44.760 | that it accelerates the rate at which you digest that food.

01:14:47.780 | And indeed it does.

01:14:49.660 | Clearing out of glucose from your system

01:14:52.560 | can be accomplished through a number of different means,

01:14:54.820 | but light movement or exercise

01:14:57.220 | does increase gastric emptying time.

01:14:59.880 | So for instance,

01:15:01.400 | if you were to eat a meal that ended at 8 PM

01:15:05.720 | and then plop to the couch, watch TV,

01:15:09.020 | or get on your computer or go to sleep,

01:15:12.680 | it would be five or six hours until you have transitioned

01:15:16.520 | from a fed state to a fasted state.

01:15:19.360 | However, you can accelerate that considerably

01:15:22.400 | by taking a 20 or 30 minute, just light walk.

01:15:25.860 | It doesn't have to be speed walking.

01:15:27.260 | It certainly doesn't have to be jogging,

01:15:28.460 | but just walking outside or moving around.

01:15:31.880 | So glucose clearing is an important aspect of the transition

01:15:36.520 | from the fed state to the fasted state.

01:15:38.860 | And just a light walk can allow you to do that.

01:15:41.300 | Now, if you can't get outside,

01:15:42.640 | some people will go through the gymnastics literally

01:15:46.600 | of doing things like air squats and pushups

01:15:48.800 | and things like that.

01:15:49.640 | And indeed those will increase the expression of things

01:15:52.200 | like Glut4 and things that mobilize glucose into muscles

01:15:56.480 | and things of that sort.

01:15:57.320 | But, you know, under most conditions,

01:15:59.400 | most people aren't doing pushups after dinner,

01:16:01.240 | or certainly if you've had a big meal,

01:16:03.120 | just taking a light walk can be beneficial.

01:16:06.120 | In addition, you could consider doing intense exercise.

01:16:11.160 | Now you wouldn't necessarily want to do that

01:16:12.980 | immediately after eating.

01:16:14.160 | So let's take a look at what high intensity training

01:16:17.360 | of any kind does to blood glucose.

01:16:19.800 | Because in this case,

01:16:20.640 | it turns out that when you do high intensity training

01:16:23.360 | actually has opposite effects on blood glucose,

01:16:26.560 | depending on whether or not you do it early

01:16:28.260 | or later in the day.

01:16:29.840 | So a fairly recent study looked at so-called HIIT training,

01:16:33.040 | high intensity interval training,

01:16:34.880 | which of course can take many different forms.

01:16:37.000 | It can take the form of circuit training with weights.

01:16:39.580 | It can take the form of, you know, burpees and pushups

01:16:42.060 | and sprints and all sorts of different things.

01:16:44.100 | But high intensity interval training is typically training

01:16:47.000 | that gets people's heart rates up, you know,

01:16:49.480 | well above 70% of maximum,

01:16:51.820 | and then brief periods of rest and then repeating.

01:16:54.900 | And how long the high intensity interval training,

01:16:56.700 | of course, will also vary.

01:16:58.420 | There are very brief, you know,

01:17:00.640 | six or 12 or 15 minute workouts.

01:17:02.960 | Some people can carry on with high intensity interval

01:17:05.540 | training for up to 45 or maybe even 60 minutes

01:17:08.420 | in extreme cases.

01:17:09.360 | But when you look at the studies that have explored high

01:17:13.420 | intensity interval training and its effect on blood glucose,

01:17:16.720 | there are a couple of studies that leap out.

01:17:18.520 | For instance,

01:17:19.360 | one that emphasized that blood glucose levels will actually

01:17:22.120 | increase if high intensity interval training is performed

01:17:24.740 | early in the day and will decrease if high intensity

01:17:27.780 | interval training is performed later in the day.

01:17:31.000 | Now, the purpose for this exploration was not to explore

01:17:36.000 | clearance of blood glucose for sake of intermittent

01:17:39.080 | fasting.

01:17:39.920 | It was mainly focused on athletic performance and whether

01:17:42.360 | or not that was better early in the day or later in the day,

01:17:44.360 | et cetera.

01:17:45.560 | But we can extract some information from these studies that

01:17:50.020 | are beneficial for sake of understanding glucose clearing.

01:17:52.920 | If you have ingested food throughout the afternoon and

01:17:58.100 | evening and late in the day,

01:17:59.100 | and you're thinking about going to sleep and you'd like to

01:18:01.800 | enter sleep in a way that is less fed and more fasted,

01:18:05.840 | then engaging in high intensity interval training in the

01:18:08.700 | afternoon will lower or evening,

01:18:11.240 | I should say will lower blood glucose.

01:18:14.040 | And in that way will help you accelerate your transition

01:18:16.640 | into the fastest state provided you don't ingest something

01:18:19.260 | after the high intensity interval training.

01:18:21.540 | Now is the increase in blood glucose that occurs from high

01:18:25.300 | intensity interval training early in the day,

01:18:27.560 | is that detrimental?

01:18:28.660 | Not necessarily so that oftentimes is associated with the

01:18:32.560 | shuttling of nutrients to the muscles that have just done a

01:18:34.840 | lot of hard work.

01:18:35.940 | So it's not that high intensity interval training should not

01:18:39.240 | be done early in the day.

01:18:40.380 | In fact, for many people,

01:18:41.320 | including myself training early in the day,

01:18:44.080 | just for the way that my psychology and biology works is

01:18:46.520 | always better for me than training later in the day.

01:18:49.040 | And the other important thing to mention is that high

01:18:51.700 | intensity interval training done late in the day can be

01:18:55.060 | beneficial from the perspective of glucose clearing,

01:18:58.520 | lowering blood glucose and helping transition from the fed

01:19:01.920 | to the fasted state in preparation for sleep.

01:19:04.920 | However, if you're ingesting caffeine or anything to engage

01:19:08.840 | in that high intensity interval training in a way that

01:19:10.920 | prevents you from getting to sleep, well,

01:19:12.800 | then it's going to be detrimental overall.

01:19:14.960 | So the reason I mentioned this is of course,

01:19:18.000 | because it's nice to know that light walks after dinner or

01:19:21.000 | any other meal for that matter or high intensity interval

01:19:23.640 | training provided it's done in the second half of the day,

01:19:25.800 | can lower blood glucose and speed the transition from fed to

01:19:29.880 | fasted states.

01:19:31.280 | But I also mention it because what we are really trying to

01:19:34.900 | achieve when we partake in intermittent fasting,

01:19:38.200 | so-called time restricted feeding is what we're really

01:19:40.900 | trying to do is access unfed states or fasted states.

01:19:45.900 | It's not really about when you eat and what you do.

01:19:48.480 | It's about extending the duration of the fasting period,

01:19:52.080 | as long as you can,

01:19:53.760 | in a way that's still compatible with your eating, right?

01:19:56.880 | Not the other way around.

01:19:58.760 | And this gets back to this key feature of our biology,

01:20:02.080 | which is that what we eat, when we eat, when we exercise,

01:20:05.960 | when we view light,

01:20:06.880 | it's about setting a context or a set of conditions in your

01:20:10.200 | brain and body.

01:20:11.460 | So it's not so much about the activities that you undergo.

01:20:14.220 | It's about the activities you undergo and their relationship

01:20:17.600 | to one another over time.

01:20:19.500 | And so in this way,

01:20:21.420 | it really beautifully highlights the way that your biology is

01:20:24.340 | interacting all the time.

01:20:25.560 | Light is setting when you're going to be awake and when

01:20:27.340 | you're going to be asleep,

01:20:28.620 | when you eat is going to be determining when you're going to

01:20:30.500 | be awake and when you're going to be asleep and when you eat

01:20:33.300 | is also going to be determining when you are able to clear

01:20:37.140 | out debris from your brain and body and repair the various

01:20:41.040 | cells and mechanisms of your body,

01:20:42.720 | when you're able to reduce those inflammatory cytokines

01:20:45.700 | throughout your body.

01:20:46.940 | And this is really the beauty of time-restricted feeding,

01:20:49.680 | which is it's not really about restricting your feeding.

01:20:52.560 | It's about accessing the beauty of the fasted state.

01:20:56.000 | Now, there are other ways to clear out blood glucose that

01:20:59.980 | involve supplements or prescription drugs.

01:21:02.740 | These are so-called glucose disposal agents,

01:21:06.400 | glucose disposal agents, such as metformin,

01:21:09.380 | which is a prescription drug or berberine,

01:21:12.460 | which is an over the counter substance will lead to very

01:21:15.940 | dramatic reductions in blood glucose.

01:21:18.580 | And so they shift you from a fed to a fasted state.

01:21:21.180 | And I know many people who take berberine before eating

01:21:25.980 | meals that include a large number of carbohydrates,

01:21:28.940 | for instance, as a way to clear out glucose.

01:21:32.100 | Now I've tried berberine before.

01:21:33.580 | And what I can tell you is that if you take berberine,

01:21:36.540 | which by the way is very much like metformin,

01:21:38.480 | its effects are almost identical to metformin in fact,

01:21:41.000 | but it's much less expensive and it's over the counter.

01:21:43.820 | If you take berberine and you have not ingested

01:21:46.180 | carbohydrates, many people, including myself,

01:21:49.500 | experience a splitting headache.

01:21:52.140 | You become hypoglycemic because it is a glucose clearing

01:21:55.540 | agent.

01:21:56.380 | So if you're going to experiment with things like

01:21:58.220 | metformin and or berberine or similar,

01:22:01.100 | you want to be very cautious that you're not clearing out

01:22:04.260 | blood glucose, that's already low.

01:22:06.580 | And the dose response for this varies tremendously from one

01:22:10.280 | individual to the next.

01:22:11.600 | And there's a strong circadian component.

01:22:14.020 | So some people react very well to berberine early in the

01:22:17.200 | day, but find that later in the day,

01:22:19.060 | it provides extreme headaches for some people,

01:22:22.560 | it's the opposite.

01:22:23.660 | So I caution you in exploring things like berberine and

01:22:27.180 | metformin that you should expect to experience a number of

01:22:30.720 | physical and psychological effects that may work for you,

01:22:34.240 | might be great for you, but might also not be great for you.

01:22:37.160 | Nowadays,

01:22:38.000 | there are a number of commercially available,

01:22:39.700 | continuous glucose monitors.

01:22:41.660 | I've tried one of these.

01:22:42.500 | It involves putting what's essentially a patch with a little

01:22:46.060 | needle that goes into your skin, which is continuing,

01:22:48.240 | continually, excuse me,

01:22:49.260 | monitoring your blood glucose.

01:22:50.740 | And you can look at it at an app on your phone.

01:22:52.620 | And you can learn a lot that way about how different foods

01:22:55.020 | impact the increases and decrease in blood glucose.

01:22:58.660 | If you're doing experiments with berberine or metformin,

01:23:01.020 | you can see how those impact your blood glucose.

01:23:03.980 | You can see how exercise hit training or otherwise impact

01:23:07.240 | impacts blood glucose.

01:23:08.860 | Excuse me again.

01:23:09.700 | It's very hard to assess blood glucose without a continuous

01:23:14.360 | blood glucose monitor.

01:23:15.420 | And if you're not using one,

01:23:16.800 | you're mainly going to be relying on subjective things like,

01:23:19.560 | oh, I feel like I have low blood sugar.

01:23:21.780 | I feel shaky.

01:23:23.180 | Like I have high blood sugar or shaky.

01:23:24.580 | Cause you have low blood sugar.

01:23:25.580 | So I have to say that glucose clearing agents that involve a

01:23:30.580 | walk or exercise moderate or intense are going to be a lot

01:23:35.500 | easier to titrate and adjust the levels of,

01:23:38.780 | then things that you're going to take,

01:23:40.140 | where you have to ingest the dosage.

01:23:41.520 | And then once you ingest a certain dosage,

01:23:43.740 | you're along for the ride,

01:23:44.820 | at least until the effects of that particular compound wear

01:23:47.260 | off, it doesn't mean those things don't have utility.

01:23:49.460 | It doesn't mean people aren't using them because many

01:23:51.420 | people are, but they are potentially a very sharp blade.

01:23:56.420 | That is a double sided blade.

01:23:58.900 | So I encourage you to approach those with caution.

01:24:01.020 | If you decide to at all,

01:24:03.060 | it's worth thinking about what the low blood glucose state

01:24:06.540 | is and why it's beneficial,

01:24:08.820 | as well as why it might produce headaches.

01:24:11.100 | And in some cases can also adjust the effects of other

01:24:13.700 | hormones in the fasted state.

01:24:16.020 | A number of different proteins that are expressed in cells

01:24:20.180 | undergo changes in their expression.

01:24:21.820 | We talked about this earlier.

01:24:23.380 | When we are fasted,

01:24:24.980 | we tend to reduce the activity of a particular protein

01:24:28.540 | called mTOR mammalian target of rapamycin mTOR is very

01:24:33.220 | active in cells while they are growing.

01:24:35.420 | So throughout development,

01:24:37.100 | it's also very active in cancers of various kinds.

01:24:40.320 | mTOR needs to be what's called phosphorylated.

01:24:44.340 | If you don't know what that means, don't worry about it.

01:24:45.900 | But phosphorylation is a manner in which certain proteins

01:24:49.620 | are altered so that they can actually be functional within

01:24:52.300 | cells. mTOR is associated with cell growth of all kinds,

01:24:55.460 | healthy and unhealthy.

01:24:56.820 | When mTOR is phosphorylated, there's a marker called PS6.

01:25:02.460 | So phospho mTOR expresses PS6.

01:25:05.540 | If this is all escaping you, don't worry about it.

01:25:08.320 | Phospho mTOR and PS6 are reduced by fasting.

01:25:12.460 | Now this makes sense if you think about it,

01:25:14.180 | because eating and growth are associated with each other.

01:25:17.300 | Fasting is not necessarily anti-growth,

01:25:21.960 | but it is not pro-growth.

01:25:23.500 | And when we fast, we see increases in cells of things like

01:25:26.900 | AMPK, the sirtuins, things like transcription factors,

01:25:31.160 | like FOXO, ATF and ketones or ketone bodies.

01:25:34.720 | You may have heard of the ketogenic diet.

01:25:36.620 | What's the point of all this biochemistry.

01:25:38.160 | It's not to just blitz you with a bunch of cellular biology

01:25:41.440 | and biochemistry.

01:25:42.660 | It's to say that we have cell growth pathways involving

01:25:45.140 | mTOR and PS6.

01:25:47.580 | And we have cell repair and cell shrinkage processes

01:25:52.580 | that are associated with AMPK, the so-called sirtuins,

01:25:56.060 | which Dr. David Sinclair from Harvard and others are famous

01:25:59.180 | for discovering and understanding things like AMPK.

01:26:04.100 | These two different divergent pathways of cell growth

01:26:07.060 | and cell breakdown and repair.

01:26:10.180 | And by breakdown, I mean actual clearance,

01:26:12.260 | autophagy and repair.

01:26:14.980 | Those can be triggered by being in either the fed

01:26:17.680 | or the fasted state.

01:26:18.980 | So one way I'd like you to think about the fed state,

01:26:21.680 | not just eating, but having recently eaten

01:26:24.540 | or the fasted state, meaning high blood glucose

01:26:27.940 | and or you've recently eaten or are currently eating

01:26:31.980 | or drinking calories is that when you eat

01:26:34.780 | or when you don't eat, when you're fed, when you're fasted,

01:26:37.100 | you are either promoting cellular growth of all kinds

01:26:40.180 | or you're promoting cellular repair and clearance

01:26:43.460 | of all kinds.

01:26:44.460 | And so, again, this is about setting conditions

01:26:46.860 | in the brain and body.

01:26:48.300 | It's not so much about when you eat food A or B,

01:26:52.440 | it leads to increases in mTOR.

01:26:54.980 | Anytime you eat any food,

01:26:56.860 | doesn't matter if it's plant-based, animal-based, fat,

01:26:59.940 | protein, carbohydrate, doesn't matter.

01:27:01.840 | You are biasing your system towards a biochemical state

01:27:04.960 | of cell growth.

01:27:05.840 | And anytime you haven't eaten for a while

01:27:08.300 | or blood glucose is low, you're biasing your system

01:27:11.500 | toward a state of cellular repair.

01:27:13.900 | And this is why people who do not suffer

01:27:17.480 | from any blood glucose regulation issues,

01:27:20.300 | take things like berberine as glucose disposal agents

01:27:23.080 | or take metformin.

01:27:23.920 | I'm not necessarily suggesting that you do that,

01:27:26.380 | but it's because those things mimic fasting.

01:27:29.180 | They create situations in the body that promote things

01:27:32.060 | like AMPK and the sirtuins and others to push your body

01:27:35.540 | and your system down a route of repair,

01:27:37.820 | even though you might've just eaten a meal an hour ago.

01:27:40.660 | Along the lines of the health benefits

01:27:42.540 | of intermittent fasting,

01:27:44.300 | there are nice data showing improvements

01:27:46.820 | in the gut microbiome and in particular,

01:27:51.000 | in the treatment of irritable bowel syndrome

01:27:53.420 | and other forms of colitis in time-restricted feeding,

01:27:57.620 | meaning time-restricted feeding seems to be able

01:28:00.020 | to assist people with those conditions,

01:28:02.980 | following the general parameters that I discussed before,

01:28:05.420 | eight hours and so forth.

01:28:06.700 | Why and how?

01:28:08.700 | Well, by way of intermittent fasting,

01:28:11.700 | impacting the expression of these various clock genes

01:28:14.100 | and because the clock genes impact the mucosal lining,

01:28:17.280 | the mucus lining of the gut,

01:28:19.540 | it appears that intermittent fasting can reduce the amount

01:28:24.540 | of so-called lactobacillus that's present in the gut

01:28:28.000 | and lactobacillus is when in high levels is correlated

01:28:31.840 | with a number of different metabolic disorders.

01:28:34.300 | At the same time, time-restricted feeding seems

01:28:36.440 | to enhance the proliferation of some of the gut microbiota

01:28:41.060 | like oscillobacter and some of the other ones

01:28:43.900 | that promote healthy mucosal lining

01:28:46.420 | and that promote better overall intestinal function.

01:28:50.480 | So these are pathways that have now been established

01:28:53.400 | and it appears that intermittent fasting

01:28:55.060 | isn't just modulating these processes,

01:28:57.340 | but is actually having a direct effect

01:28:58.940 | on the mucosal lining in a way

01:29:00.180 | that favors a healthier gut microbiome.

01:29:02.740 | So it should come as no surprise that many people

01:29:05.140 | who experience gut issues benefit

01:29:07.040 | from restricting their feeding window to eight hours or so

01:29:09.780 | per every 24 hour period.

01:29:11.700 | The other very exciting finding about intermittent fasting

01:29:14.420 | is one of the major health issues these days

01:29:17.260 | is the proliferation of so-called

01:29:20.500 | non-alcoholic fatty liver disease.

01:29:23.440 | 30 years or so non-alcoholic fatty liver disease

01:29:26.300 | was exceedingly rare to see in the clinic

01:29:28.260 | except in alcoholics.

01:29:30.580 | Fatty deposits in the liver are bad.

01:29:32.580 | It is essentially liver disease.

01:29:34.900 | Nowadays, children and adults are showing up

01:29:38.140 | with non-alcoholic fatty liver disease.

01:29:40.180 | Some of these people are obese, others are not,

01:29:42.940 | but it's a serious health concern

01:29:44.700 | and it's growing in numbers all the time.

01:29:48.040 | A recent study that was published in Cell Reports Medicine

01:29:51.700 | just a couple of weeks ago tested the hypothesis

01:29:54.860 | whether or not the gut microbiome

01:29:57.340 | or so-called brown fat tissue is impacting the liver health

01:30:01.780 | and in particular non-alcoholic fatty liver disease.

01:30:06.020 | The short takeaway from the study

01:30:07.340 | is that contrary to what was previously thought,

01:30:10.260 | the gut microbiome, while very important

01:30:12.660 | for a number of other processes in the body,

01:30:15.420 | doesn't seem to be related

01:30:16.920 | to this non-alcoholic fatty liver disease.

01:30:18.900 | This is surprising to people or should be

01:30:20.960 | to those of you that have been following

01:30:22.360 | the gut microbiome literature.

01:30:23.660 | However, brown fat, which is a healthy fat

01:30:27.860 | that we have between our two scapulae and in our upper neck,

01:30:30.740 | it doesn't tend to be blubbery type fat pads,

01:30:32.860 | but it sits deep to the skin,

01:30:34.560 | but creates a thermogenic effect in the body that is helpful

01:30:38.660 | for reducing the amount of other fat,

01:30:41.480 | the type of fat that we're more typically used

01:30:43.520 | to thinking about and talking about,

01:30:44.680 | white fat and pink fat that's subcutaneous fat

01:30:47.040 | around the abdomen and so forth.

01:30:48.640 | Brown fat seems to have a direct correlation

01:30:52.980 | with the lack of non-alcoholic fatty liver disease.

01:30:55.580 | What this study showed was that in people

01:30:58.280 | that have diminished concentrations of brown fat,

01:31:02.940 | there is a higher probability

01:31:05.780 | of having non-alcoholic fatty liver disease.

01:31:07.820 | Now, the good news is brown fat stores can be increased.

01:31:10.680 | And again, this isn't going to create blubber of brown fat.

01:31:13.260 | This is going to create increased thermogenesis

01:31:15.060 | and actually make people leaner.

01:31:17.220 | And brown fat has a number

01:31:18.200 | of other important positive effects.

01:31:20.500 | Now, this is interesting because cold exposure

01:31:23.420 | of anywhere from one to three minutes,

01:31:25.660 | two or four times per week, or maybe even 10 minutes,

01:31:27.660 | two to four times per week can increase brown fat stores.

01:31:31.140 | Also, time restricted feeding has now been tied

01:31:34.540 | to the density of brown fat stores.

01:31:37.620 | So time restricted feeding also seems

01:31:39.480 | to positively increase brown fat stores,

01:31:42.100 | probably because of the way that brown fat stores relate

01:31:44.300 | to epinephrine and adrenaline,

01:31:45.820 | which tend to go up when we're fasted.

01:31:48.220 | What does this all mean?

01:31:49.140 | This means for sake of liver health

01:31:51.640 | and for sake of reducing or maybe preventing,

01:31:54.500 | or even potentially, I want to underline potentially,

01:31:57.320 | reversing non-alcoholic fatty liver disease,

01:31:59.940 | time restricted feeding also appears to be beneficial.

01:32:03.380 | Many people out there are interested

01:32:05.060 | in optimizing their hormones.

01:32:07.540 | And as we mentioned earlier, insulin is a hormone

01:32:09.820 | and time restricted feeding seems

01:32:11.620 | to have very positive effects

01:32:12.920 | on overall insulin profiles and so forth.

01:32:15.980 | But anytime you mention hormones,

01:32:18.620 | people immediately seem to leap

01:32:19.980 | to the sex steroid hormones, testosterone and estrogen,

01:32:23.220 | because indeed they have powerful effects,

01:32:24.900 | both in the short term and the long term,

01:32:27.540 | in terms of our mental and physical health

01:32:29.700 | and performance.

01:32:31.120 | There's at least one study that's explored the effects

01:32:33.660 | of time restricted eating on performance,

01:32:36.780 | athletic performance, immune function and body composition.

01:32:40.620 | This was a study by Morrow et al

01:32:43.060 | that was performed on elite cyclists.

01:32:45.060 | So I want to point that out.

01:32:46.660 | It was a randomized control trial,

01:32:49.420 | but what's really nice about this study is

01:32:51.740 | that it explored a number of different hormonal parameters

01:32:56.340 | in people that were using time restricted eating

01:32:59.640 | or that had a more extended eating window.

01:33:02.160 | And they tracked everything very carefully.

01:33:04.560 | And the amount of food they were eating

01:33:06.980 | was actually pretty considerable, 4,800 calories.

01:33:10.260 | So that's a lot of calories,

01:33:11.820 | but then again, they were very active.

01:33:13.960 | And they've measured a number

01:33:15.900 | of different things related to VO2 max, et cetera.

01:33:18.940 | Performance and overall performance at what they did,

01:33:23.580 | cycling, is not the point that I want to emphasize here.

01:33:26.860 | Although there were some positive effects

01:33:28.900 | on their performance related to time restricted eating.

01:33:32.040 | The point I want to talk about relates

01:33:35.280 | to things that presumably relate to most everybody,

01:33:38.320 | which are the effects on things like glucose,

01:33:41.960 | thyroid hormone, testosterone, sex hormone binding globulin,

01:33:45.880 | which can bind up testosterone

01:33:48.200 | and prevent the so-called free form of testosterone,

01:33:50.960 | which is the one that has most of the actions

01:33:53.340 | in the brain and body.

01:33:55.120 | And the major takeaway from this study was

01:33:57.680 | that time restricted feeding of the same amount of calories

01:34:02.260 | as the so-called control condition, okay?

01:34:04.720 | Same calories, but either compact

01:34:06.740 | throughout the 24 hour cycle to an eight hour feeding window

01:34:10.020 | or allowing them to eat over a larger feeding window

01:34:13.760 | did lead to significant decreases in free testosterone.

01:34:18.060 | And I think a number of people

01:34:19.160 | will raise their eyebrows to that and think,

01:34:21.240 | oh, well then maybe time restricted feeding is not for me.

01:34:24.080 | There are a number of important considerations.

01:34:25.680 | Of course, one is while the decrease

01:34:29.080 | in free testosterone was significant,

01:34:31.680 | it's also going to depend on where people start out.

01:34:33.960 | So if somebody has already low or modest levels

01:34:37.000 | of testosterone and it drops by 10 or 20%,

01:34:39.880 | that could lead them into a state

01:34:41.840 | of poor performance and wellbeing.

01:34:43.720 | Whereas if somebody has higher testosterone,

01:34:46.000 | a decrease won't necessarily do that.

01:34:47.880 | So it's important to take that into consideration.

01:34:50.080 | This is why I'm always such a fan

01:34:51.280 | of people doing their blood work

01:34:53.480 | and knowing what's going on under the hood for them.

01:34:56.520 | A very interesting change in hormonal profile

01:34:59.520 | was cortisol, so-called stress hormone.

01:35:02.240 | Cortisol of course is also naturally released

01:35:04.560 | early in the day in a healthy way

01:35:05.880 | to wake you up and promote alertness,

01:35:08.280 | but you don't want its levels to be too high

01:35:10.820 | or to have peaks in cortisol late in the day.

01:35:13.600 | It's actually correlated with depression

01:35:15.040 | and a number of other untoward things.

01:35:17.780 | I would have thought that by restricting a feeding window

01:35:22.120 | to a particular time each day,

01:35:24.400 | that these hard training cyclists

01:35:26.160 | would have undergone increases in serum cortisol.

01:35:29.360 | And in fact, the opposite was true.

01:35:32.000 | They had significant reductions in serum cortisol

01:35:35.680 | as a consequence of time restricted feeding.

01:35:37.680 | I should mention there were significant reductions

01:35:39.600 | in serum cortisol also in the control group,

01:35:42.680 | but not to the same extent.

01:35:44.640 | And the two groups did differ significantly

01:35:46.640 | from one another.

01:35:48.040 | Now, this is important because if you just look

01:35:50.680 | at one hormone, testosterone, you'd say,

01:35:52.800 | okay, based on these data, time restricted feeding

01:35:55.880 | is reducing testosterone levels significantly,

01:35:58.520 | even though the number of calories is quite high

01:36:00.540 | and is held constant across the study.

01:36:02.520 | But in fact, because cortisol is lower,

01:36:05.680 | it may mean that the effects of testosterone

01:36:08.120 | or the reduction in testosterone is offset.

01:36:10.260 | And that's because cortisol and testosterone

01:36:12.500 | are always in this somewhat of a dance

01:36:14.920 | in terms of cortisol,

01:36:16.460 | inhibiting the effects of testosterone largely

01:36:18.920 | and vice versa.

01:36:20.160 | So it is interesting and important to look

01:36:22.380 | at the total gallery of hormones.

01:36:24.400 | And they did look at a number of hormones.

01:36:26.700 | They looked at other inflammatory markers.

01:36:28.480 | Those were not increased.

01:36:29.720 | That's not surprising.

01:36:30.740 | If you remember back to the 2012 Sachin Panda study,

01:36:33.740 | this early pioneering study on time restricted feeding,

01:36:36.980 | they saw reductions in stress hormones

01:36:39.600 | and in inflammatory markers in time restricted feeding mice.

01:36:43.400 | And here, this also seems to be the case in humans.

01:36:46.200 | So the takeaway is for sake of hormone health,

01:36:50.440 | time restricted feeding is compatible

01:36:53.900 | with quality hormone health,

01:36:55.520 | even in high-performing athletes.

01:36:57.920 | Based on everything we know and that we've discussed,

01:36:59.900 | I would not suggest that people restrict their feeding

01:37:02.200 | window to less than eight hours,

01:37:03.720 | especially if they're training hard on a regular basis.

01:37:06.500 | And it's not just athletes that should pay attention to this

01:37:10.820 | when we are working very hard,

01:37:12.240 | when we are psychologically stressed,

01:37:14.280 | when we are studying for exams,

01:37:16.960 | or we are in conflict with somebody on a regular basis,

01:37:20.980 | that creates a stress in the body

01:37:22.880 | that's very similar to that of physical training.

01:37:25.420 | The body and brain don't distinguish

01:37:26.840 | between physical stress and mental stress.

01:37:28.580 | It's all nervous system.

01:37:29.720 | Remember that it's just cortisol and adrenaline.

01:37:32.020 | There's no special hormone just for physical stress

01:37:35.400 | versus psychological stress.

01:37:37.220 | So again, in thinking about what sort of feeding window

01:37:39.960 | will be right for you,

01:37:40.780 | we arrive back at this eight hour time bin

01:37:43.960 | that seems more or less flexible for most conditions,

01:37:47.680 | even high-performing elite athletes.

01:37:49.680 | And I would say just by logical extension,

01:37:52.720 | even for people that have a lot of stress in their life.

01:37:55.080 | And I personally wouldn't suggest that people

01:37:58.080 | who have a lot of stress in their life

01:37:59.320 | or the potential for stress in their life

01:38:01.240 | shorten their feeding window much shorter than eight hours,

01:38:05.540 | because then you would expect that you would start

01:38:08.080 | to increase some of the inflammatory markers.

01:38:10.400 | You would increase the stress hormones

01:38:12.200 | and you would be decreasing things like testosterone

01:38:15.800 | and estrogen and some of the sex steroid hormones.

01:38:17.720 | So again, it's all about context and the eight hour window.

01:38:20.500 | It isn't holy, but seems to be a really useful guide

01:38:23.200 | to extract the great health benefits of which,

01:38:27.800 | there are many in of which we've discussed

01:38:29.680 | from intermittent fasting, time-restricted feeding,

01:38:33.760 | and yet that it could still be compatible

01:38:35.900 | with decent social schedules

01:38:37.620 | and for maintaining hormone health.

01:38:40.080 | In keeping with this, for women that are trying

01:38:42.420 | to maintain ovulatory cycles,

01:38:44.080 | or for couples that are trying to get pregnant,

01:38:46.760 | I think it's also important to not create a feeding window

01:38:50.260 | that's too short.

01:38:52.520 | The relationship between feeding and body fat stores

01:38:56.760 | and glucose and leptin and hormones

01:38:59.600 | is a well-established one.

01:39:00.680 | And we can summarize it very easily here,

01:39:02.280 | although I've done several episodes related to this

01:39:04.200 | previously on optimizing hormone health.

01:39:06.560 | But basically we undergo puberty when there's enough food

01:39:11.560 | and there's enough body fat,

01:39:13.560 | that the body fat sends a signal to the brain called leptin.

01:39:16.320 | That's a hormone that comes from body fat,

01:39:17.840 | signals to the brain to turn on puberty.

01:39:20.960 | That's puberty, but even as adults,

01:39:23.520 | for women that are menstruating,

01:39:25.140 | there needs to be sufficient leptin signaling to the brain

01:39:27.940 | in order to maintain ovulation

01:39:29.340 | because of the way that the brain communicates

01:39:31.000 | with the pituitary and the ovaries.

01:39:32.800 | Similarly for men, fasting or extreme exercise plus fasting,

01:39:37.800 | we now know reduces testosterone.

01:39:42.260 | Its impacts are not exactly clear.

01:39:45.700 | However, if you reduce food intake,

01:39:48.480 | either in total calories or in duration too much,

01:39:52.080 | you will suffer a drop in sperm counts, fertility will drop.

01:39:55.720 | And this makes sense.

01:39:56.560 | The body is communicating to the brain

01:39:58.140 | whether or not conditions are sufficient in the body

01:40:01.360 | to reproduce and to presumably and hopefully

01:40:05.360 | support the health and wellbeing of those offspring.

01:40:08.040 | So there's a logical link between body fat and eating

01:40:10.960 | and how much food is available to you

01:40:13.400 | and how long it's available to you

01:40:15.200 | and the signals in the brain

01:40:16.200 | that allow for reproductive success.

01:40:18.440 | There are some data that pointed differences

01:40:20.960 | in the effects of intermittent fasting

01:40:22.840 | for males versus females.

01:40:25.480 | Those data right now only come from mice.

01:40:28.020 | That study was published by Sachin Panda recently.

01:40:30.440 | We still await the studies in humans.

01:40:33.560 | Some people do not do well on intermittent fasting,

01:40:36.360 | either in terms of mood or hormone health.

01:40:38.840 | And so everyone needs to determine for themselves

01:40:40.720 | whether or not having a time restricted feeding window

01:40:43.560 | is good for them,

01:40:44.640 | how long that time restricted feeding window should be.

01:40:47.080 | I think eight hours is kind of a nice minimum to adhere to

01:40:50.280 | based on everything that we've covered today.

01:40:52.220 | And for some people,

01:40:54.800 | time restricted feeding is not going to be compatible

01:40:57.020 | with hormone health for them.

01:40:58.140 | For them eating more meals spread throughout the day,

01:41:01.720 | presumably smaller meals, same caloric intake

01:41:04.560 | is going to be more beneficial for their hormones.

01:41:06.740 | This is something that is going to be individual

01:41:08.600 | and is going to have to be determined

01:41:10.760 | on an individual basis.

01:41:11.940 | However, if you're going to try time restricted feeding,

01:41:15.220 | I do want to remind you that taking a period of three to seven

01:41:17.980 | or ideally 10 days to transition into it,

01:41:20.060 | not just going flipping from eating to three meals a day

01:41:23.300 | that span from 6 AM to 10 PM

01:41:25.160 | and suddenly going to an eight hour feeding window,

01:41:27.140 | but rather winnowing down that feeding window

01:41:30.440 | about an hour or so per day

01:41:32.360 | is going to allow the hormone systems of your body,

01:41:34.640 | including leptin, the hypocretinorexin system,

01:41:37.400 | which are systems within the body that signal to the brain

01:41:39.520 | that food is about to come,

01:41:41.400 | allowing those systems to adjust

01:41:43.240 | so that you're not overwhelmingly hungry, irritable,

01:41:46.200 | and you're not throwing your whole hormone system

01:41:48.400 | out of whack.

01:41:49.720 | I keep coming back to this eight hour feeding window

01:41:52.000 | and I want to provide a little more basis for it

01:41:54.200 | and just to encourage that it's not completely arbitrary.

01:41:57.400 | The lengthy review that I mentioned earlier

01:42:01.120 | features a number of studies

01:42:02.380 | that have used this eight hour feeding window,

01:42:05.220 | but there's a particular study that I'd like to highlight,

01:42:08.240 | mainly because I don't expect people to delve

01:42:09.820 | into the full reference list of the other review.

01:42:12.900 | And this is a study that was carried out

01:42:15.020 | between Sachin Panda's lab and Christopher Verity's lab.

01:42:18.300 | So this is a collaboration.

01:42:19.740 | The study was carried out in humans

01:42:21.420 | and is entitled effects of eight hour time restricted feeding

01:42:24.580 | on body weight and metabolic disease risk factors

01:42:27.400 | in obese adults, excuse me.

01:42:30.260 | And this study essentially showed,

01:42:32.660 | I'll just read the conclusions,

01:42:34.780 | that an eight hour time restricted feeding

01:42:37.740 | produces a mild caloric restriction and weight loss

01:42:41.140 | without calorie counting.

01:42:43.700 | So that's key, right?

01:42:45.020 | These people aren't calorie counting.

01:42:46.340 | Somehow just by adhering to an eight hour window,

01:42:49.360 | they are taking in fewer calories than they're burning off

01:42:54.360 | and clinically it reduced blood pressure.

01:42:57.860 | So I mentioned the study,

01:42:58.840 | not because there aren't many others

01:43:00.360 | involving the eight hour feeding window, also in humans,

01:43:03.240 | but because the eight hour feeding window

01:43:04.880 | has been tested in obese adults and non-obese adults.

01:43:07.800 | And there are even a few studies in children.

01:43:10.440 | So this eight hour window seems to be

01:43:12.200 | a really good rule of thumb and a kind of anchor

01:43:15.160 | around which we can each think about

01:43:18.000 | incorporating time restricted feeding.

01:43:19.900 | There are of course, other patterns of feeding.

01:43:22.180 | And while some people have engaged in longer fasts

01:43:26.520 | of 24 hours, 36 hours or more,

01:43:31.060 | alternate day fasting, meaning eating one day,

01:43:35.200 | not eating the next day, or in some cases,

01:43:37.040 | eating one day and eating very few calories,

01:43:39.320 | 500 or 600 calories the next day has been tested.

01:43:43.420 | A few studies have also looked at eating

01:43:46.140 | a sort of maintenance level of calories for five days

01:43:48.380 | and then taking two days and fasting clear through

01:43:52.080 | or eating very few calories, 300 or 500 calories.

01:43:55.860 | In fact, there's a sort of a community online

01:43:59.400 | of people that are exploring longer fasts

01:44:01.260 | for sake of trying to offset dementia

01:44:03.200 | or reverse effects of dementia.

01:44:05.500 | Thus far, at least in my awareness,

01:44:08.580 | there isn't any quality clinical peer reviewed study

01:44:12.220 | on that yet for sake of dementia.

01:44:14.820 | Although I await those studies

01:44:16.020 | and if anyone's aware of them,

01:44:17.540 | please send me a link in the comments.

01:44:19.740 | But alternate day fasting has gotten

01:44:22.740 | the so-called safe bill of health.

01:44:24.540 | This has been written up,

01:44:25.680 | meaning that people didn't suffer bone loss.

01:44:27.460 | They didn't suffer any major detrimental effects.

01:44:31.260 | It does seem that it can create significant weight loss

01:44:35.940 | and can help with obese individuals,

01:44:38.600 | that it can reduce resting blood glucose.

01:44:40.820 | And every other day fasting in many cases

01:44:43.300 | can produce more rapid effects on weight loss

01:44:46.200 | and reductions in blood glucose than time restricted feeding.

01:44:49.380 | However, every other day type fasting for most people

01:44:53.940 | is not going to be feasible.

01:44:56.120 | They're just not going to be able to do that

01:44:57.540 | for a long period of time.

01:44:58.480 | And what hasn't really been done is the followup

01:45:00.720 | to see whether or not people who do every other day fasting

01:45:03.340 | or five days of eating followed by two days of fasting,

01:45:06.120 | whether or not that leads to a rebound in weight gain,

01:45:08.740 | whether or not that leads to a rebound

01:45:10.140 | in blood glucose, et cetera.

01:45:11.740 | So for now, the eight hour feeding window

01:45:13.980 | and time restricted feeding seems to be the most tested,

01:45:18.580 | supported in animal studies and in human studies,

01:45:22.420 | and the one around which I think most people should orient

01:45:25.660 | if they're considering getting into time restricted feeding.

01:45:28.240 | It's also sort of hard to imagine how one could include

01:45:31.860 | a significant exercise schedule or work schedule

01:45:35.760 | on every other day fasting.

01:45:37.100 | Remember, in any study, people are often being compensated

01:45:40.300 | or at least are incentivized in some way

01:45:42.960 | to adhere to the study.

01:45:44.820 | This is one of the major issues that I have with any study

01:45:47.260 | that says that three or four different diets

01:45:49.500 | are essentially equal in terms of their ability

01:45:52.560 | to produce weight loss.

01:45:54.040 | Adherence is very different in the outside world

01:45:57.160 | where you don't have a researcher monitoring you,

01:45:59.260 | where you're not logging all your food.

01:46:01.080 | Most people don't do that consistently.

01:46:03.240 | And we can take a little bit of a neuroscience perspective

01:46:05.380 | on this to try and arrive at what the best kind

01:46:07.560 | of organization of an eating plan, or if we wanted

01:46:10.960 | to call it a diet, we could, would be for you.

01:46:13.300 | Many people find it easier to just not eat

01:46:17.360 | for certain periods of each 24 hour cycle

01:46:20.060 | than to eat smaller portions.

01:46:21.600 | Portion control is very hard for some people.

01:46:24.520 | For other people, it's manageable.

01:46:26.980 | But people like me, I don't eat half the croissant.

01:46:30.640 | I don't think it's a real thing.

01:46:32.280 | It's not available to me, I should say.

01:46:35.320 | Now, of course I could eat just half a croissant,

01:46:38.080 | but I noticed that when I eat the croissant,

01:46:39.740 | because they're so delicious,

01:46:41.280 | that it creates a rise in blood glucose,

01:46:43.680 | a rise in the other hormones and chemicals

01:46:46.480 | that are associated with ingesting delicious,

01:46:48.420 | highly palatable food.

01:46:50.120 | And it's actually a lot of work for me

01:46:52.220 | to just eat half the croissant.

01:46:54.480 | There's something that's much more thoroughly satisfying

01:46:58.840 | about eating the entire croissant.

01:47:00.680 | And actually there's something that's somewhat satisfying

01:47:03.360 | about not eating the croissant at all.

01:47:05.120 | And just knowing that later I can eat the whole croissant.

01:47:07.400 | Now that's me.

01:47:08.360 | Other people find that they don't have any trouble

01:47:11.560 | with portion control.

01:47:13.000 | That for them, just eating small bits of food

01:47:14.820 | throughout the day is what sets them

01:47:16.340 | in the right psychological and physical state

01:47:18.600 | for sake of work, et cetera.

01:47:20.040 | And I mentioned work and mental focus

01:47:22.000 | because one of the aspects of fasting

01:47:24.320 | that have drawn a lot of people

01:47:26.040 | to time restricted feeding and fasting

01:47:28.320 | is the clarity of mind that people get.

01:47:31.480 | When first of all, they don't have to think about

01:47:34.000 | when they're going to eat,

01:47:34.840 | because they know when their eating window begins.

01:47:37.320 | They also don't have to think about

01:47:38.680 | regulating their behavior

01:47:40.760 | because they already know when they're going to eat

01:47:43.160 | and when they're not going to eat.

01:47:44.200 | Whereas when you're restricting portions,

01:47:46.320 | you actually have to make decisions all the while.

01:47:48.960 | You know, and I think I, like many people decide,

01:47:51.280 | well, you know, is that exactly half?

01:47:53.360 | Or could I have like another rung on the croissant?

01:47:55.600 | This kind of thing.

01:47:56.420 | I don't negotiate with food.

01:47:57.680 | That's why I like a time restricted feeding window.

01:48:00.440 | I know I'm going to eat for, in my case,

01:48:01.920 | I use a 10 hour feeding window or so,

01:48:04.400 | and I'll eat the whole croissant.

01:48:05.760 | I just don't have to think about it.

01:48:07.840 | Now, the food choices that you make

01:48:10.120 | inside of that feeding window

01:48:11.280 | are of course also going to be very important.

01:48:13.280 | Certain foods will increase blood glucose

01:48:15.080 | such that you're going to get hungrier and hungrier.

01:48:16.880 | Others will maintain lower blood glucose

01:48:19.120 | and will allow you to be more controlled

01:48:21.960 | in the foods that you pursue.

01:48:23.980 | Those are all individual considerations

01:48:25.800 | that are deserving of their own entire episode.

01:48:28.200 | But I do want to point out that the advantage

01:48:31.100 | of time restricted feeding is that it involves

01:48:33.680 | a lot of the decision-making in the brain,

01:48:35.700 | the so-called go, no-go circuitries of our basal ganglia,

01:48:39.320 | if you want to know those areas that control them.

01:48:41.360 | Anytime we have to restrict a behavior,

01:48:43.640 | that's called a no-go.

01:48:45.540 | Anytime we engage in a behavior, that's a go.

01:48:48.320 | No-go behaviors require a lot of what's called

01:48:50.800 | top-down control, and it's very metabolically demanding.

01:48:53.880 | And so time restricted feeding allows you to depart

01:48:56.780 | from the whole no-go go negotiation

01:48:59.380 | that you have to undergo when you have to restrict portions.

01:49:03.560 | And so I think this is a reason why many people

01:49:05.240 | have gravitated towards time restricted feeding

01:49:07.600 | and why for people that don't want to have to think

01:49:10.040 | about all that, it's just very straightforward.

01:49:12.960 | One of the more hot button issues out there

01:49:15.120 | is whether or not given equal amounts of caloric intake

01:49:19.400 | and equal amounts of activity

01:49:23.040 | and equal amounts of nutrients, et cetera,

01:49:25.440 | whether or not restricting food to a particular window

01:49:28.980 | biases more weight loss toward fat loss

01:49:32.580 | versus loss of other tissues.

01:49:34.180 | 'Cause of course, when we lose weight,

01:49:35.300 | we can lose that from any number of different

01:49:37.320 | storage sites within the body,

01:49:39.280 | muscle, water, glycogen, or fat.

01:49:44.280 | Now, this is such a hot button issue

01:49:47.040 | that I almost don't want to get into it,

01:49:48.140 | but I'm going to get into it anyway,

01:49:49.360 | because there are data that are very interesting.

01:49:53.120 | This is covered in the review that I mentioned earlier

01:49:56.540 | that describes how if people follow

01:50:00.160 | a time restricted feeding schedule

01:50:01.920 | for long periods of time, so 60 days or longer,

01:50:05.880 | there are some metabolic changes in the way

01:50:08.600 | that people metabolize energy

01:50:10.840 | that do seem to shift the system toward more fat loss

01:50:14.640 | relative to burning of other tissues

01:50:17.120 | when in a state of caloric restriction.

01:50:19.120 | And I want to say when in a state of caloric restriction,

01:50:21.640 | because there's really no way to cheat the system,

01:50:23.920 | there's no way that you can ingest far more calories

01:50:26.200 | than you burn or excrete.

01:50:28.080 | When I say excrete, I certainly don't suggest this,

01:50:31.360 | but there, bulimics and other people

01:50:34.080 | that have eating disorders will use laxatives

01:50:35.880 | as a way to eliminate food quickly from their system

01:50:38.100 | so it can't be converted into fat or other forms of energy.

01:50:41.680 | That's a very, in that case, it's a pathological situation,

01:50:45.480 | but in general, calories in versus calories out,

01:50:48.000 | as I mentioned earlier, is this kind of foundational element

01:50:50.680 | but in states of caloric restriction,

01:50:53.260 | meaning sub maintenance intake,

01:50:55.340 | time restricted feeding does seem to buy us

01:50:59.920 | more of the energy burned to compensate for that deficit

01:51:04.880 | from fat and the way it accomplishes it is very interesting.

01:51:08.560 | It turns out that it drives more fat loss

01:51:11.440 | by way of increasing a hepatic lipase.

01:51:14.160 | This is something called LIPC,

01:51:15.800 | hepatic means of the liver and lipase,

01:51:18.280 | which anytime you hear A-S-E means it's an enzyme.

01:51:22.320 | So it seems to increase hepatic lipase.

01:51:24.840 | So it increases the enzyme that metabolizes fat

01:51:28.280 | for lipolysis and energy production

01:51:30.240 | and reduces something called CIDEC, C-I-D-E-C,

01:51:34.400 | which is a lipid droplet associated and lipolysis inhibitor.

01:51:38.620 | Now that's a mouthful, no pun intended,

01:51:41.240 | but what CIDEC really is,

01:51:44.440 | this lipid droplet associated molecule,

01:51:47.440 | is it can inhibit lipolysis.

01:51:50.380 | So extended periods of time restricted feeding,

01:51:54.340 | meaning eight hour feeding window or 10 hour feeding window

01:51:57.940 | that's obeyed for several months or more

01:52:01.400 | seems to allow the system to shift toward burning more fat

01:52:06.400 | or rather using a higher percentage of fat

01:52:10.840 | when in a caloric deficit.

01:52:13.160 | Now, I doubt that this is going to resolve

01:52:15.580 | the truly barbed wire, almost hairball,

01:52:18.560 | ridiculous online debates about

01:52:20.400 | whether or not time restricted feeding

01:52:21.780 | is better than another feeding schedule.

01:52:23.340 | Look, I don't think any particular feeding schedule

01:52:25.460 | is holy.

01:52:26.460 | If you are sub caloric, meaning fewer calories burned

01:52:29.200 | than calories ingested, you're going to lose weight.

01:52:31.560 | But the data seemed to point to the fact that

01:52:33.700 | if you do time restricted feeding

01:52:35.260 | for a fairly long duration of time and you maintain that,

01:52:39.000 | that you are increasing these lipases

01:52:41.060 | that increase lipolysis, energy use from fat,

01:52:45.820 | and you're decreasing the lipid droplet

01:52:48.160 | associated lipolysis inhibitors.

01:52:50.320 | So it's both a, you're removing the break

01:52:53.080 | and you're pressing on the accelerator of fat loss.

01:52:55.820 | I think that this logically points to a case in which

01:53:00.820 | using time restricted feeding with a sub caloric intake

01:53:05.180 | seems to be, at least to my mind,

01:53:07.220 | the most scientifically supported way

01:53:09.300 | to ensure that a significant portion of the weight

01:53:12.980 | that one loses is from body fat stores.

01:53:15.520 | Any discussion about fasting would be incomplete

01:53:18.700 | without a discussion about what does

01:53:20.580 | and does not break a fast.

01:53:23.100 | However, there is no black and white answer

01:53:26.060 | to that question.

01:53:27.020 | And you should immediately understand why.

01:53:29.820 | It's because eating and not eating

01:53:33.820 | are not equivalent to fed and fasted.

01:53:36.660 | It depends on when you ate, how much you ate,

01:53:40.640 | and where you are in your circadian cycle.

01:53:44.760 | We can actually arrive at a simple answer

01:53:46.780 | to whether or not something breaks the fast or not.

01:53:49.140 | Now, the technical way to go about this would be

01:53:51.020 | to wear a continuous glucose monitor

01:53:53.300 | and to ingest little bits of food of different kinds

01:53:56.220 | or large amounts of food of different kinds

01:53:58.260 | and measure blood glucose,

01:53:59.820 | because ultimately blood glucose is the readout

01:54:02.860 | of whether or not your system is in a fed or fasted state.

01:54:05.380 | There are other parameters too, of course,

01:54:06.940 | but that's the dominant one.

01:54:08.560 | Insofar as the scientific literature says,

01:54:13.440 | drinking water will not break your fast.

01:54:17.560 | Drinking tea will not break your fast.

01:54:21.640 | Drinking coffee provided it is black coffee

01:54:23.900 | will not break your fast.

01:54:25.300 | Ingesting caffeine in pill form will not break your fast.

01:54:30.820 | There are other things that won't break your fast.

01:54:33.160 | For instance, eating one peanut when deep in a fasted state

01:54:37.140 | will not break your fast.

01:54:38.840 | Eating a whole handful of peanuts

01:54:40.260 | might not even break your fast

01:54:41.760 | if you are in a very low glucose state.

01:54:44.720 | However, if you just finished a meal

01:54:46.300 | that included carbohydrates

01:54:47.960 | or it was a very large meal of any kind an hour ago,

01:54:52.000 | yes, indeed, eating one peanut could break your fast.

01:54:55.800 | So it's all contextual.

01:54:57.840 | That's what's really important to understand.

01:54:59.720 | Unless you're going to wear a continuous glucose monitor

01:55:02.780 | and unless you're going to wear a continuous glucose monitor

01:55:05.860 | and set an absolute numerical threshold

01:55:08.900 | for what it is to break your fast,

01:55:11.340 | I think there are some simple rules that we can follow.

01:55:14.100 | First of all, anything that involves sugar,

01:55:19.040 | in particular, simple sugars

01:55:20.500 | can potentially break your fast.

01:55:21.820 | And there's actually a study on this,

01:55:23.380 | which shows that if people ingest even one gram of sugar

01:55:30.220 | post dinner, if they had a full meal for dinner,

01:55:33.400 | that can actually disrupt the expression

01:55:36.120 | of some of the circadian genes related to fasting

01:55:39.660 | and to sleep and sleep-related fasting.

01:55:41.920 | Now that's pretty extreme.

01:55:43.180 | It's almost kind of scary to think about,

01:55:45.480 | but that's how sensitive our system is

01:55:47.540 | if we already have somewhat elevated blood glucose

01:55:50.720 | from a meal that we ate an hour or so ago.

01:55:53.400 | Whereas if we have run for an hour or trained hard,

01:55:58.120 | high intensity training, and we haven't quite reached

01:56:01.480 | the beginning of our so-called feeding window,

01:56:04.400 | will eating a small amount of food take us out of that fast?

01:56:09.400 | Well, depends on what the food is.

01:56:11.880 | If it's mostly fat, probably not.

01:56:14.640 | A number of people out there nowadays

01:56:15.960 | talk about so-called fat fasting.

01:56:17.700 | Fat fasting is a way to kind of wriggle past

01:56:20.920 | the stringency of either eating or not eating

01:56:25.240 | as a black and white rule for feeding window

01:56:28.200 | versus non-feeding window.

01:56:29.600 | So some people will ingest medium chain triglycerides,

01:56:33.400 | so-called MCTs, or people will ingest fats only

01:56:36.760 | until their official feeding window begins.

01:56:38.920 | So these are sort of how the negotiations

01:56:40.840 | that people carry out tend to go.

01:56:42.880 | But fat, of course, won't increase blood glucose

01:56:45.720 | and insulin as much as carbohydrates will.

01:56:47.880 | Protein will have sort of an intermediate effect.

01:56:50.900 | And as I mentioned earlier, ingesting carbohydrates

01:56:53.120 | with some fat will tend to blunt the rise in glucose

01:56:57.060 | and will extend the duration over which glucose is released.

01:57:00.380 | So we really can't say food X or beverage X breaks a fast.

01:57:05.380 | However, at the extremes, we can say that.

01:57:09.880 | For instance, if you drink a can of soda pop,

01:57:13.700 | unless you just ran an ultra marathon,

01:57:16.040 | you're breaking your fast, okay?

01:57:17.760 | You eat a piece of pizza, you're breaking your fast.

01:57:19.960 | If you eat purely fats, maybe, probably not.

01:57:23.620 | If you've been fasting for five hours or more,

01:57:27.020 | strictly fasting for five hours or more.

01:57:29.100 | So you can start to see where there's a lot of wiggle room

01:57:32.040 | and it's very contextual.

01:57:33.520 | And this is why any posts that you see

01:57:36.120 | or any information that you see that something does

01:57:38.180 | or does not break your fast that doesn't place it

01:57:40.120 | in the context of when the last time you ate

01:57:43.520 | and what you ate and your activity and your time

01:57:47.320 | within the circadian clock schedule of 24 hours,

01:57:50.480 | it's a sort of meaningless discussion.

01:57:52.520 | So in general, I think what's really useful,

01:57:54.760 | if you're not going to wear a continuous glucose monitor,

01:57:57.540 | is to try and be fairly strict

01:57:59.760 | about when you initiate your feeding window

01:58:01.720 | and when you stop your feeding window.

01:58:03.400 | And as time evolves and you establish a more regular routine

01:58:06.820 | of eating certain kinds of foods and not others

01:58:08.600 | that are right for you,

01:58:09.440 | 'cause as I've emphasized before on this podcast,

01:58:11.660 | and I will continue to emphasize,

01:58:13.160 | keto works great for some people,

01:58:15.160 | vegetarian keto works great for some people,

01:58:17.240 | carnivore diet works great for other people.

01:58:20.240 | Some people are omnivores, some people are carnivores,

01:58:22.640 | some people are vegan.

01:58:24.480 | All of that is great and fine by me.

01:58:26.280 | Everyone has to establish what's right for them.

01:58:27.980 | Today, we've really bypassed the discussion

01:58:31.280 | about foods of a particular origin or type,

01:58:34.720 | animal-based or plant-based,

01:58:36.260 | but all the same rules apply within this thing

01:58:39.620 | that we're call intermittent fasting

01:58:41.480 | or time-restricted feeding.

01:58:42.760 | So what breaks a fast will depend and what you want to eat

01:58:46.540 | or what you are willing to eat,

01:58:48.200 | that's a totally separate manner from when you eat.

01:58:51.320 | But as we've established, when you eat is vitally important.

01:58:55.200 | Some of you are probably wondering whether or not

01:58:57.800 | artificial sweeteners or non-artificial plant-based

01:59:01.480 | sweeteners like Stevia break a fast.

01:59:04.400 | This will vary somewhat.

01:59:06.880 | And I have to say the data on this are somewhat mixed.

01:59:10.680 | There is evidence that when people ingest

01:59:14.320 | artificial sweeteners, that it can create a transient

01:59:17.820 | increase in blood glucose followed by a transient decrease

01:59:21.400 | in blood glucose below baseline.

01:59:23.880 | This is thought to explain the increase in hunger

01:59:26.300 | caused by ingestion of things like aspartame and sucralose

01:59:29.100 | and things of that sort.

01:59:30.360 | There are not a lot of good studies exploring

01:59:33.040 | the plant-based non-sugar sweeteners,

01:59:36.360 | things like Stevia, even things like monk fruit,

01:59:39.340 | which is a separate category into itself.

01:59:41.680 | There aren't a lot of studies on this.

01:59:43.040 | I think most people need to establish this for themselves.

01:59:45.540 | The best way of course would be to wear a continuous glucose

01:59:47.800 | monitor to go into a fasted state of either one hour

01:59:50.680 | or two hours, or maybe you've been fasting all night

01:59:52.600 | and then ingest Stevia in whatever form you want

01:59:55.600 | or coffee in whatever form you want with sucralose

01:59:59.000 | or aspartame, et cetera,

02:00:00.440 | setting aside the discussion about the effects

02:00:02.880 | of these things on the gut microbiome,

02:00:04.720 | which is a different topic entirely.

02:00:07.180 | I think it's fair to say that in moderation,

02:00:10.020 | the plant-based non-sugar sweeteners like Stevia,

02:00:13.800 | in particular, Stevia, seem to have a minimal impact

02:00:17.160 | on overall blood glucose when considered

02:00:19.280 | over a fairly large time bin.

02:00:20.920 | Aspartame and sucralose, saccharin,

02:00:24.660 | I think we can say more or less the same,

02:00:26.060 | but as soon as you get into a discussion about those,

02:00:27.940 | you also have to get into a discussion

02:00:29.420 | about some of the evidence published in nature

02:00:32.940 | and other excellent journals now,

02:00:35.140 | pointing to the fact that when consumed in excess,

02:00:37.900 | not when consumed in moderation,

02:00:39.980 | but when consumed in excess,

02:00:41.200 | that those might have some detrimental effects

02:00:42.900 | on the gut microbiome.

02:00:44.560 | So do artificial sweeteners break a fast?

02:00:48.240 | Depends on the amount, depends on the type.

02:00:50.360 | And in general, I think you're probably okay,

02:00:52.960 | provided that you're not indulging in them too often.

02:00:56.160 | However, some people,

02:00:57.760 | just by virtue of tasting something sweet,

02:01:00.400 | feel a spike in their appetite that makes it harder

02:01:02.780 | for them to adhere to the feeding window.

02:01:04.720 | And so this is why you can imagine

02:01:06.460 | that a really well-controlled study on this

02:01:08.940 | would be very hard to carry out.

02:01:10.260 | And I'm not really sure that it's worth our tax dollars

02:01:12.580 | to actually design and carry out a study like that,

02:01:15.500 | because there would be so much individual variation

02:01:18.140 | in terms of discipline in adhering to the feeding window,

02:01:21.380 | whether or not people experience increases and drops

02:01:23.700 | in blood glucose, how that impacts them,

02:01:25.300 | whether or not they're exercising,

02:01:26.340 | it just becomes an infinite variable space, as we say,

02:01:29.940 | in experimental science.

02:01:31.300 | So you really have to determine that for you,

02:01:33.040 | but I don't think that we can fairly say

02:01:36.480 | that artificial sweeteners break a fast.

02:01:38.620 | I think that would be incorrect to say.

02:01:40.540 | Earlier, we were talking about glucose disposal agents,

02:01:43.460 | both behavioral and compound-based things

02:01:46.780 | like metformin and berberine.

02:01:48.160 | And in fact, cinnamon is even a mild glucose disposal agent.

02:01:52.100 | It can actually reduce blood glucose.

02:01:54.300 | Lemon and lime juice, believe it or not,

02:01:56.600 | can lower blood glucose.

02:01:58.500 | You may have experienced this before

02:01:59.780 | of eating something very, very sweet

02:02:01.460 | and almost feeling kind of overwhelmed

02:02:03.000 | and kind of poisoned by how sweet it is,

02:02:04.780 | especially if you're not accustomed

02:02:06.440 | to eating a lot of sugary things.

02:02:09.020 | One quick remedy for that is actually a half lime

02:02:12.220 | or a half lemon squeezed into juice and drinking that

02:02:15.060 | just by virtue of the taste and by virtue of the fact

02:02:18.980 | that it will reduce blood glucose,

02:02:20.940 | you'll notice that that effect

02:02:22.220 | almost immediately disappears.

02:02:24.100 | That's not magic.

02:02:25.180 | That's the effects of acidity on blood glucose levels.

02:02:28.900 | So there are a number of things that can adjust

02:02:31.380 | blood glucose.

02:02:32.380 | They're not necessarily disposal agents.

02:02:34.060 | They're not sweeping it out of the bloodstream

02:02:36.060 | in the same way that berberine or metformin would,

02:02:38.120 | or that high intensity exercise

02:02:39.920 | at the appropriate times of day would.

02:02:41.640 | But there is one particular thing that one can ingest

02:02:45.580 | that can help manage psychologically and performance wise

02:02:50.580 | through the fasting portion of the intermittent fasting

02:02:55.060 | and get you to your feeding window.

02:02:57.220 | And that's salt.

02:02:59.140 | I've talked a little bit about this on the podcast before,

02:03:01.460 | but because neurons use salt, sodium and potassium

02:03:06.380 | and magnesium,

02:03:07.220 | the so-called electrolytes in order to perform their magic

02:03:10.500 | of chemical and electrical signaling,

02:03:12.140 | everything you do depends on chemical

02:03:13.560 | and electrical signaling and all that chemical

02:03:15.480 | and electrical signaling requires electrolytes

02:03:18.680 | in some form or another neurons run on the passage of ions

02:03:23.620 | like sodium in and out of their cell membranes,

02:03:27.820 | or I should say across their cell membranes to be accurate.

02:03:31.240 | Many people find that the kind of lightheadedness,

02:03:34.020 | the shakiness that's accustomed

02:03:36.420 | with having slightly low blood sugar can be offset

02:03:40.540 | by taking a half teaspoon or so of sea salt,

02:03:44.620 | or even just a tiny pinch of salt

02:03:46.300 | and putting into some water and drinking it.

02:03:48.980 | Some people find because of the glucose lowering effects

02:03:54.300 | of acidity, that if they're feeling kind of shaky

02:03:56.420 | and not well, and they put some lemon juice into water

02:03:59.140 | and drink that it drops their blood glucose further.

02:04:01.880 | So there's a common practice nowadays

02:04:04.320 | that's discussed on the internet of waking up,

02:04:06.000 | drinking some water with some lime or lemon juice in it

02:04:08.660 | with a little pinch of salt.

02:04:09.960 | I think that little pinch of salt is a good idea.

02:04:12.100 | What is it doing?

02:04:12.940 | How is it offsetting all this?

02:04:14.120 | Well, salt water actually has a mild effect

02:04:18.040 | as a glucose disposal agent,

02:04:20.020 | but it has a stabilizing effect on blood volume.

02:04:23.400 | And so because sodium brings with it water

02:04:26.800 | and the so-called osmolarity of your blood and your body

02:04:30.660 | depends on the salt levels in your blood and brain and body.

02:04:35.660 | Many people find that if they're feeling shaky,

02:04:38.040 | they're feeling lightheaded, they can't concentrate.

02:04:39.800 | They think they need sugar or food,

02:04:41.400 | but what will actually remedy that is some salt.

02:04:44.520 | And I know a number of people

02:04:45.700 | that have incorporated this practice

02:04:47.040 | and have written to me and saying, oh, you know,

02:04:48.560 | if I just take a little bit of salt and some water,

02:04:50.780 | they may or may not include the lemon or lime juice.

02:04:52.500 | They immediately feel better

02:04:54.020 | and find that it's actually quite straightforward

02:04:56.060 | to get out to that,

02:04:58.060 | to wait until the feeding window kicks in.

02:05:00.640 | This is especially true for people that are using caffeine

02:05:03.940 | because when you ingest caffeine,

02:05:05.180 | you actually excrete a lot of water as a diuretic effect.

02:05:08.300 | And with that water goes salt.

02:05:10.160 | So it actually causes you to excrete sodium.

02:05:12.580 | Now, the role of sodium in blood pressure and hypertension

02:05:16.420 | is quite controversial.

02:05:18.780 | Science Magazine,

02:05:19.640 | one of the premier scientific journals out there

02:05:23.460 | had a special issue all about salt some years ago

02:05:26.020 | talking about the research around hypertension.

02:05:28.580 | Indeed, people with chronic hypertension

02:05:30.540 | or high blood pressure or very high blood pressure

02:05:32.500 | in particular should be wary of ingesting too much sodium.

02:05:35.500 | But for most people ingesting sodium,

02:05:38.420 | provided they drink enough water

02:05:40.500 | and they don't have chronic hypertension

02:05:42.400 | or high blood pressure is actually beneficial.

02:05:45.860 | That doesn't mean you should be drinking seawater.

02:05:47.220 | Doesn't mean you should be overindulging in salt,

02:05:50.300 | but many people find that they can manage their mental

02:05:53.700 | and physical state and even feel really terrific,

02:05:56.460 | real clarity of mind and really enjoy their fast

02:06:00.020 | when they're ingesting sufficient salt.

02:06:01.660 | And all it requires really is a small pinch of salt,

02:06:03.660 | ideally Himalayan or sea salt,

02:06:05.000 | if you want to get fancy about it,

02:06:06.140 | but table salt would be fine.

02:06:08.060 | And just drinking that in some water,

02:06:11.140 | maybe with lemon or lime juice

02:06:12.320 | to offset the taste a little bit

02:06:14.500 | can really stabilize one's jitters

02:06:17.500 | and can stabilize the mind.

02:06:19.140 | And you might also notice can offset that churning

02:06:23.720 | and yearning and appetite where you can't imagine

02:06:26.660 | going another five minutes before eating something,

02:06:28.580 | suddenly you feel okay.

02:06:29.500 | And that has to do with a lot of the effects of blood volume

02:06:32.420 | caused by ingesting salt in the appropriate amounts.

02:06:35.360 | In other words, sometimes you think you need food,

02:06:38.160 | but what you really need is salt

02:06:39.580 | and salt can make you feel better immediately.

02:06:41.940 | I'd like to mention two excellent zero cost resources.

02:06:45.260 | If you're going to explore time restricted feeding,

02:06:47.620 | or maybe if you already are doing time restricted feeding,

02:06:50.840 | I have no affiliation to either of these.

02:06:53.800 | The first is the website that I mentioned before,

02:06:55.860 | My Circadian Clock,

02:06:56.980 | which is the website hosted by Sachin Panda and colleagues.

02:07:00.400 | There are a lot of resources there

02:07:01.860 | where you can log your food intake,

02:07:03.460 | get information about time restricted feeding,

02:07:05.260 | all the science, the ongoing studies, et cetera.

02:07:08.260 | The other is the so-called Zero app

02:07:10.940 | that makes it very easy to

02:07:14.220 | mark when you're beginning your feeding,

02:07:17.540 | window and when you're ending your feeding window.

02:07:19.440 | And in so doing,

02:07:20.560 | marking when you are beginning your fast

02:07:22.360 | and ending your fast,

02:07:23.340 | or at least initiating the beginning of the unfed state,

02:07:27.580 | as we could more accurately call it.

02:07:29.560 | It's a terrific app.

02:07:30.580 | I've used it from time to time.

02:07:31.960 | I don't tend to use it in an ongoing basis

02:07:34.900 | because I'm just sort of used to eating

02:07:36.580 | at a particular time of day now.

02:07:38.620 | But anytime I've shifted that window,

02:07:41.240 | for instance, a few weeks ago,

02:07:42.880 | I started moving that protein intake

02:07:44.660 | in my entire feeding window earlier in the day.

02:07:47.160 | And because that takes some attention on my part,

02:07:49.940 | because I'm not used to doing that,

02:07:51.640 | I've been using the Zero app and I like it quite a lot.

02:07:54.080 | It logs your progress and it gives you averages

02:07:56.080 | and you can see how many other people are fasting.

02:07:57.860 | Again, totally zero cost.

02:07:59.380 | I actually don't know who owns that app,

02:08:01.120 | but I think they've done an excellent job.

02:08:03.120 | The interface is really terrific.

02:08:04.580 | And as far as I know, it's available for Apple and Android,

02:08:07.340 | but it's at least available for Apple phones,

02:08:09.320 | which is the type of phone I happen to have.

02:08:11.460 | So check those out.

02:08:13.140 | My circadian clock, you just put that into Google,

02:08:15.500 | you'll find it and the Zero app,

02:08:17.460 | both excellent zero cost resources.

02:08:20.520 | In a moment, I'd like to review the parameters

02:08:22.860 | of a ideal feeding schedule for you

02:08:26.900 | and give you the variables that you can plug in

02:08:29.020 | to your lifestyle and your preferences.

02:08:31.540 | There are a couple of things that I would place

02:08:33.020 | into the category of frequently asked,

02:08:36.220 | somewhat odd, but still worthy of discussion.

02:08:40.100 | For instance, people have asked,

02:08:42.600 | will brushing your teeth with toothpaste break your fast?

02:08:45.640 | I think unless you're swallowing the toothpaste, no.

02:08:49.540 | Now, if you really want to run out

02:08:50.820 | and get a continuous glucose monitor and brush your teeth

02:08:53.020 | and you can evaluate that, but no.

02:08:55.320 | People have asked, will a half glass of wine after dinner,

02:08:59.620 | a couple hours after dinner, break your fast?

02:09:01.640 | Absolutely.

02:09:02.840 | It absolutely will.

02:09:03.700 | And it's been demonstrated to do that

02:09:05.920 | based on the one gram of sugar,

02:09:08.640 | kind of eerie or scary effect that I talked about before.

02:09:11.800 | Scary and eerie because it just seems like one gram of sugar.

02:09:15.140 | How could it do that?

02:09:15.980 | But these are metabolic processes

02:09:18.160 | and they are very sensitive post meal.

02:09:21.780 | A few months back,

02:09:22.800 | I did an experiment wearing a continuous glucose monitor.

02:09:26.460 | And I got a surprise when I discovered

02:09:29.240 | that going into a sauna increases my blood glucose

02:09:32.460 | quite a bit.

02:09:33.300 | It actually spikes it as high as a meal.

02:09:35.500 | And then it tends to drop back down to baseline

02:09:37.820 | or even slightly below baseline afterwards.

02:09:40.640 | When I talk to people about this, somebody said,

02:09:43.820 | oh, it's got to be that the continuous glucose monitor

02:09:46.780 | was getting disrupted by the heat in the sauna.

02:09:48.840 | That's actually not the case.

02:09:50.720 | Turns out that when you go in a sauna,

02:09:54.020 | because you dehydrate, you're losing water.

02:09:57.660 | I wasn't drinking water and you're dropping a lot of water.

02:10:00.320 | The concentration of sugar in your blood actually goes up.

02:10:03.520 | And I actually put these data out

02:10:06.160 | in a social media post on Twitter.

02:10:08.460 | And people were kind of shocked to see how much

02:10:11.100 | a sauna can spike your blood glucose.

02:10:13.320 | Now I do practice time restricted feeding,

02:10:15.760 | intermittent fasting.

02:10:16.600 | I'm not super strict about it.

02:10:17.900 | I use a kind of eight to 10 hour ish window,

02:10:21.340 | either early in the day or late in the day.

02:10:23.700 | I saw this effect of the sauna.

02:10:25.560 | Personally, the psychological and physical health effects

02:10:30.460 | of the sauna are valuable enough to me

02:10:33.140 | that I continue to use it.

02:10:34.460 | I just not concerned about this increase in blood glucose

02:10:37.420 | to the extent that I'm going to eliminate sauna.

02:10:39.560 | I like to use the sauna three or four times

02:10:41.620 | a week before sleep.

02:10:43.240 | So I'll use it an hour or two before sleep.

02:10:44.840 | And yes, indeed, it creates this big spike

02:10:47.020 | in blood glucose that then drops based on change

02:10:49.580 | in the concentration of blood sugar.

02:10:51.860 | I'm just not going to worry about it.

02:10:53.000 | Now, if you're concerned about blood glucose spikes,

02:10:55.760 | then you might be worried about it.

02:10:57.440 | But in my case, it was one of those things

02:10:59.360 | where it was interesting and it was worthy of discussion,

02:11:02.820 | I thought, because it was somewhat surprising to me,

02:11:04.580 | although it makes perfect sense why this would be the case.

02:11:06.820 | But at the end of the day, literally,

02:11:09.340 | it just makes sense for me to get in the sauna.

02:11:11.800 | Okay, so now you've heard a lot of science.

02:11:13.660 | You've heard a lot of examples, even a few anecdotes.

02:11:17.000 | And let's come up with the ideal intermittent fasting,

02:11:22.000 | AKA time-restricted feeding schedule for you.

02:11:26.460 | And when I say ideal, I mean,

02:11:28.380 | what are the variables that are negotiable?

02:11:30.680 | What are the ones that are non-negotiable?

02:11:33.320 | What is ideal for you will depend on the context

02:11:36.380 | of your life and what you are willing to do consistently.

02:11:40.140 | So first of all,

02:11:42.980 | we established based on the discussion with Sachin,

02:11:46.100 | who is truly the premier world expert in this area,

02:11:49.820 | who knows the animal and human scientific literature

02:11:53.580 | better than anybody has written this incredible review.

02:11:56.260 | And for whom I consulted that you do not want to ingest food

02:12:01.260 | for at least, I want to emphasize at least 60 minutes

02:12:05.700 | post waking up.

02:12:06.760 | Second, you want to avoid ingesting any food

02:12:12.380 | of any kind, even one gram of sugar.

02:12:15.240 | Remember, this is the ideal.

02:12:16.980 | One gram of sugar even would be too much

02:12:19.620 | for the two to three hours prior to bedtime.

02:12:22.860 | He also mentioned, ideally,

02:12:26.020 | you are spending eight hours in bed.

02:12:28.460 | I didn't tell you that earlier.

02:12:29.460 | I saved that for now,

02:12:31.020 | but ideally you are sleeping that entire eight hours,

02:12:34.400 | but simply by being in bed for that eight hours

02:12:36.740 | and avoiding food after waking for an hour

02:12:39.040 | and before bed for two to three hours,

02:12:42.640 | you're starting to build out the duration

02:12:44.220 | of this fasted period.

02:12:46.020 | Remember that the sleep related fasting

02:12:52.060 | is particularly important for the health benefits

02:12:54.700 | of time restricted feeding.

02:12:56.800 | Again, the sleep related fasting is especially important

02:12:59.860 | because of all the cellular repair processes

02:13:03.560 | that occur in the liver, in the gut, in the microbiome,

02:13:06.420 | in the brain, all over the body.

02:13:08.820 | And because of the way that that coordinates the expression

02:13:11.060 | of the clock genes that are then going to wick out

02:13:14.300 | and have many other positive effects on health,

02:13:17.680 | including weight and fat loss.

02:13:20.540 | But in addition to that, liver health, et cetera.

02:13:23.100 | An eight hour feeding window as a target

02:13:28.100 | seems to be the best target feeding window,

02:13:31.900 | at least by my read of the literature

02:13:33.680 | and in discussing it with such in.

02:13:36.000 | Shorter feeding windows of four to six hours

02:13:38.280 | tend to lead to overeating

02:13:40.200 | and potentially increases in weight.

02:13:42.420 | One meal per day type eating do not seem to do that,

02:13:48.340 | but those are special cases in that most people

02:13:52.100 | can't adhere to a one meal per day type schedule,

02:13:55.800 | at least not on a regular basis.

02:13:57.120 | And it's not very compatible with most social schedules.

02:14:00.080 | Although some people may be able to adhere to that

02:14:02.480 | in a straightforward way,

02:14:03.320 | but there aren't any robust studies exploring

02:14:06.680 | the advantages of one meal per day.

02:14:09.360 | So if you feel there are advantages of one meal per day

02:14:12.560 | for you, as opposed to an eight hour feeding window,

02:14:16.020 | well then by all means use a one meal per day approach

02:14:19.500 | or use a four to six hour feeding window

02:14:22.160 | and just make sure you don't overeat in that window.

02:14:26.140 | Remember that most people tend to not adhere

02:14:30.400 | to the eight hour feeding window.

02:14:31.620 | They say eight hours,

02:14:32.820 | but they tend to eat outside of the eight hours,

02:14:35.400 | a little bit on each side.

02:14:37.100 | So if your goal is a 10 hour feeding window,

02:14:41.340 | you might want to set it to nine hours or eight hours.

02:14:44.260 | If your goal is six hours,

02:14:45.500 | you might want to set it to seven or eight hours.

02:14:47.580 | And this is simply based, or I shouldn't say simply,

02:14:49.980 | this is based on thousands,

02:14:52.460 | if not tens of thousands of human subject data points

02:14:56.700 | that Sachin and colleagues have collected.

02:14:58.800 | Regular placement of the eating window

02:15:03.260 | or feeding window every 24 hours is important.

02:15:08.260 | You don't have to be absolutely rigid

02:15:10.300 | and neurotic about this,

02:15:11.780 | but you don't want it sliding around on the weekend

02:15:14.020 | so that it's starting two hours later

02:15:15.620 | and ending two hours later, a couple of days a week,

02:15:18.980 | because then you start to offset many of the positive health

02:15:22.980 | effects that have been demonstrated

02:15:24.860 | for time restricted feeding.

02:15:26.220 | Remember if you eat your food

02:15:31.220 | within a certain feeding window,

02:15:32.900 | but that feeding window shifts by a couple hours,

02:15:36.080 | it is effectively like jet lagging your system.

02:15:38.620 | It is effectively like traveling a couple of time zones over

02:15:43.100 | eating there for a few days and coming back

02:15:45.180 | when in fact you're not traveling.

02:15:48.880 | And that's because of the way that food

02:15:50.540 | adjusts the circadian clock genes.

02:15:52.660 | Now you can offset some of that through the use of light.

02:15:55.480 | And I've talked extensively about how to use light

02:15:58.000 | in previous podcasts, but again,

02:16:00.280 | early morning and all day bright light exposure

02:16:02.580 | as safely as you can, ideally from sunlight,

02:16:04.480 | not through a window, et cetera,

02:16:05.980 | avoiding bright light in the middle of the night,

02:16:07.780 | extremely important for mood offsetting,

02:16:10.600 | metabolic dysfunction, et cetera.

02:16:13.060 | Not incidentally, Sachin's early work

02:16:17.060 | was he was one of the three co-discoverers

02:16:19.920 | of the cells in the eye, the so-called melanopsin cells

02:16:22.400 | that set the central circadian clock.

02:16:24.760 | So he was a pioneer in that field,

02:16:26.180 | which led him to be a pioneer in this field and so on.

02:16:28.920 | When should that eight hour window be placed

02:16:33.260 | within each 24 hour cycle?

02:16:35.180 | Well, let's talk about ideal.

02:16:36.760 | Ideal, if you really want to maximize

02:16:39.440 | all the health benefits of time restricted feeding,

02:16:46.380 | you need to extend the fast around sleep on both sides.

02:16:50.120 | You would place it smack dab in the middle of the day.

02:16:52.680 | It would be a schedule in which you started eating,

02:16:55.740 | for instance, at 10 AM and you stopped eating at 6 PM.

02:17:00.740 | An absolutely dreadful schedule for anyone

02:17:03.340 | that wants to have some semblance of a normal life.

02:17:06.140 | In my opinion, it's not really compatible

02:17:08.820 | with most schedules,

02:17:09.880 | although some people might be able to do it.

02:17:11.760 | Maybe you and your family or your friends,

02:17:13.560 | you're eating a late breakfast

02:17:16.620 | and then you're having a late-ish lunch around 2 PM

02:17:20.120 | and then you have dinner at six.

02:17:22.180 | And then assuming that you go to bed around 9.30 or 10 PM,

02:17:26.860 | that is going to extract the maximum amount

02:17:30.800 | of weight related, body fat related,

02:17:33.240 | metabolic factor related aspects of time restricted feeding.

02:17:38.680 | Some people tend to fall into a category

02:17:42.180 | where they do best placing that feeding window

02:17:44.880 | later in the day and provided it doesn't run

02:17:48.740 | too close to your sleep.

02:17:49.660 | Remember you needed a two or three hour buffer

02:17:51.360 | before your sleep where you're not ingesting anything.

02:17:53.780 | That's in order to extract the benefits

02:17:56.380 | of time restricted feeding.

02:17:57.780 | Well, then starting your feeding window at 12 PM

02:18:01.900 | and ending at 8 PM plus or minus half an hour or so,

02:18:06.200 | day-to-day seems like a perfectly reasonable schedule

02:18:09.400 | for some people starting at 2 PM and ending at 10 PM

02:18:12.440 | will be that schedule.

02:18:13.600 | Of course, you have to take into consideration

02:18:16.620 | when you exercise, if you exercise.

02:18:19.840 | For instance, I like to exercise early in the day if I run

02:18:23.240 | or if I do some moderate or light intensity exercise,

02:18:26.560 | regardless of what type of exercise it is,

02:18:28.440 | I have no trouble waiting until my feeding window kicks in

02:18:32.280 | around noon or even 2 PM.

02:18:34.440 | But if I do high intensity weight training, for instance,

02:18:37.200 | early in the day, or if I run sprints and I do that at 7 AM

02:18:40.800 | or 8 AM by 11 AM, I am very, very hungry.

02:18:44.720 | And it's hard for me to do other things,

02:18:47.000 | concentrate, et cetera.

02:18:48.460 | Now I'm not neurotic about my feeding window.

02:18:50.740 | As I mentioned before,

02:18:51.580 | I kind of let it expand and contract a bit

02:18:53.880 | around the eight hour mark and feel perfectly free

02:18:56.480 | to do that too.

02:18:57.320 | We're talking here in ideals,

02:18:58.880 | not in necessarily practicals,

02:19:01.800 | but other people find that they're very hungry

02:19:05.520 | when they wake up early in the day.

02:19:07.240 | If you're one of these people,

02:19:08.340 | or you're somebody who really is trying to emphasize

02:19:11.740 | hypertrophy or maintenance of muscle,

02:19:14.640 | then it does seem that ingesting protein early in the day

02:19:17.740 | is beneficial, that it can be more readily converted

02:19:21.880 | into muscle tissue.

02:19:23.640 | And this has been demonstrated in at least one study.

02:19:26.480 | There's another study underway

02:19:27.720 | that's exploring this further for people that are really,

02:19:30.960 | really interested in hypertrophy and building muscle well,

02:19:33.100 | then time-restricted feeding is usually not the way they go.

02:19:36.000 | I mean, let's be honest.

02:19:37.520 | There are many people out there who are eating

02:19:39.800 | four more meals per day,

02:19:41.320 | and they're doing that from 7 AM until 8 PM.

02:19:44.680 | I realized that not everybody is overweight.

02:19:46.360 | There is an obesity crisis indeed.

02:19:48.800 | The percentage of obesity

02:19:50.000 | and non-alcoholic fatty liver disease

02:19:52.400 | is just cosmic through the roof,

02:19:53.760 | at least in this country and in other countries as well.

02:19:56.920 | This country, me in the US, but other countries as well.

02:20:01.360 | But there are, of course, people that are trying

02:20:03.140 | to gain weight or who don't want to lose weight

02:20:05.460 | or who are trying to maximize physical performance

02:20:07.880 | or hypertrophy or things of that sort.

02:20:09.440 | And so of course, time-restricted feeding for them

02:20:12.040 | might be as long as I'm awake, I'm eating.

02:20:14.680 | And I tip my hat to those people and just say,

02:20:18.680 | provided you understand what you're doing

02:20:20.360 | and the burden that that places

02:20:21.700 | on some of the other processes in your body,

02:20:23.580 | if that's right for you, then by all means, pursue that.

02:20:27.020 | Another thing that we can add to this summary

02:20:28.860 | or key points related to time-restricted feeding

02:20:32.100 | is the use of glucose disposal agents and or behaviors.

02:20:35.780 | If you find that you've eaten too close to a period of time

02:20:40.460 | in which you would prefer to be fasting,

02:20:42.140 | that's when a 30 minute brisk walk or even modest walk

02:20:46.060 | after eating can be beneficial.

02:20:49.560 | Ingesting some lemon juice or lime juice

02:20:51.980 | can help lower blood glucose somewhat.

02:20:54.860 | And then there are the things like metformin and berberine.

02:20:58.060 | There are even some supplements out there

02:20:59.340 | that combine things like berberine, cinnamon,

02:21:02.100 | which can lower blood glucose and things like chromium

02:21:06.780 | and things that have a mild effect on blood glucose.

02:21:09.140 | But berberine and metformin are very high potency

02:21:14.140 | glucose disposal agents.

02:21:16.360 | And I mentioned earlier why you would want to approach those

02:21:18.700 | with the appropriate level of caution

02:21:20.940 | and figure out the dosages for you.

02:21:22.460 | And for some people, the dosages will be zero milligrams

02:21:25.580 | is going to be ideal.

02:21:27.040 | And then of course, we discussed how making sure

02:21:29.540 | that you're ingesting enough fluids in particular water

02:21:32.240 | and salt, especially if you're using caffeine

02:21:35.660 | in order to increase your levels of alertness,

02:21:38.080 | regardless of where that caffeine source comes from coffee,

02:21:40.500 | tea or otherwise that can cause the excretion of sodium

02:21:44.380 | and can lead to a kind of shakiness, a lightheadedness

02:21:47.740 | and the feelings of hunger that may or may not

02:21:50.980 | be related to blood glucose.

02:21:52.660 | Some people genuinely need to eat.

02:21:54.980 | I certainly would not want to see people getting hypoglycemic

02:21:57.680 | to the point where it's dangerous.

02:21:59.120 | Certainly if you are diabetic, you, and in fact,

02:22:02.500 | for all people, you should consult with your physician

02:22:06.260 | when exploring any major changes to diet or additions

02:22:09.200 | or subtractions of anything, including supplementation.

02:22:11.840 | But for most people, maintaining relatively low

02:22:15.360 | to modest blood glucose levels is going to be pretty healthy

02:22:19.080 | and will allow all the positive effects

02:22:21.740 | of intermittent fasting to occur.

02:22:25.200 | And when you find that reaching that start

02:22:28.700 | to the feeding window is challenging,

02:22:30.940 | that ingesting sodium can often stabilize your system

02:22:35.860 | mentally and physically and allow you

02:22:37.460 | to reach that window often painlessly.

02:22:40.700 | And then as a final point, as I mentioned earlier,

02:22:43.660 | provided that they are consumed in low, no,

02:22:48.080 | or modest amounts, artificial sweeteners or plant-based

02:22:52.760 | non-sugar non-caloric sweeteners don't seem

02:22:56.240 | to really impact blood glucose to the extent

02:22:58.200 | that it would quote unquote, take you out of your fast.

02:23:01.520 | But that like fat fasting is something that's going

02:23:04.500 | to be highly individual and that you're going to have

02:23:06.640 | to experiment with for yourself and being able to recognize

02:23:11.120 | when you're in a fast and when you're out of a fast

02:23:14.080 | at a subjective level and not constantly having

02:23:16.120 | to measure your blood glucose or do things

02:23:18.720 | of that sort can be beneficial.

02:23:20.640 | And I think if you watch for the feelings associated

02:23:23.760 | with eating and post-eating foods of different kinds

02:23:26.460 | in different amounts, and you watch for the feelings

02:23:29.060 | associated with being fasted for long periods of time

02:23:32.200 | or short periods of time of having gotten sufficient

02:23:35.600 | sunlight of having trained hard or not trained hard

02:23:38.280 | earlier that day, et cetera,

02:23:40.240 | you can do the most important thing,

02:23:41.460 | which is to start to learn to evaluate your own system

02:23:44.740 | to run simple, safe experiments on your system in a way

02:23:48.160 | that allows you to really establish the ideal nutrition

02:23:51.900 | schedule for you, whether it be time-restricted feeding,

02:23:55.020 | AKA intermittent fasting, or some other nutritional plan.

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02:25:01.000 | During this episode and in many other previous episodes,

02:25:04.480 | I discussed supplements.

02:25:05.880 | One issue with supplements and the supplement industry

02:25:08.340 | as a whole is that the quality and amounts of supplements

02:25:12.520 | often varies tremendously.

02:25:14.280 | Therefore, we've partnered with Thorne, T-H-O-R-N-E,

02:25:16.980 | because Thorne has the absolute highest levels of stringency

02:25:19.680 | with respect to the quality of ingredients

02:25:21.760 | and the amount of the ingredients matching

02:25:24.000 | what's on the label.

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02:25:27.080 | and get 20% off any of Thorne's supplements,

02:25:29.880 | you can go to thorne.com/u/huberman.

02:25:34.880 | You'll see the list of supplements that I take,

02:25:37.080 | you can get 20% off those.

02:25:38.760 | And if you enter the Thorne site through that portal,

02:25:41.020 | you get 20% off anything that Thorne makes.

02:25:43.500 | I know we covered a lot of information today.

02:25:46.260 | I hope you learned a lot about time-restricted feeding.

02:25:49.320 | I hope you learned a lot about metabolism

02:25:52.040 | and energy and health,

02:25:53.860 | and how when you eat is as important as what you eat.

02:25:57.700 | And last, but certainly not least,

02:26:00.040 | thank you for your interest in science.

02:26:01.800 | [upbeat music]

02:26:04.380 | (upbeat music)

Effects of Fasting & Time Restricted Eating on Fat Loss & Health | Huberman Lab Podcast #41

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