The way I think about a glucose monitor, first of all, I'll say the purpose of the glucose monitor is not to game the system and get flat glucose. The purpose of the glucose monitor is curiosity. It's to start to understand how essentially an MRI for how all of our different dietary and lifestyle strategies are creating this readout of glucose in our body, which I think can be really interesting.

And in a world where so many cards are stacked against us with diet and lifestyle and where there's a lot of confusion about what's right for us, that can be very helpful in actually reducing the confusion and the cognitive load of our choices. We know that keeping your blood sugar through the course of a lifetime in a low and healthy range, so I don't mean up and down spikes during the day, but keeping your blood sugar healthy throughout the course of your lifetime is probably the best thing we can do for longevity, staying insulin sensitive, staying out of the diabetic range.

And so one thing the glucose monitor does for us is just give us more awareness and agency into what the trends of our glucose are over time, as opposed to a literally one data point snapshot once a year in the doctor's office, which is what the majority of us are used to.

I really love the idea that people who are able to wear glucose monitors every now and again, maybe once a year, maybe more than once a year, they know what their glucose is. And so they're never going to walk into a doctor's office and have a bomb dropped on them about prediabetes or type 2 diabetes, because you have the data, which is ultimately I hope the world that we can move towards for a lot of biomarkers.

So you can see trends over time, which I think is very valuable. One thing that's fascinating in terms of early prediction of metabolic disease is that you can see how long it takes your glucose to come down after a meal. So in a normal, healthy, insulin sensitive body, even if the glucose goes way up, it should come way down very quickly, because the insulin is binding to insulin receptors and the glucose is getting taken up, and it'll lower.

What is quickly over the course of-- It should be down by two hours. But from what I've actually seen in our most insulin sensitive people and also in research that looks at young healthy populations, you should basically be spiking and coming down, spike about 45 minutes and come down hour and a half, 90 minutes to two hours.

But if-- This is after, sorry, after last bite? After last bite, although it's hard to kind of exactly know. But yeah, meal is over, I would say about 45 minutes to go up to the peak and then start coming down very quickly. Now if you start to see that glucose is going up and then trailing very slowly back down to normal, maybe taking more than two hours, three hours, that is going to be one of those early indicators of potential insulin resistance.

Your body's not clearing the glucose, but that's not a metric that we use in standard practice at all. And I've actually seen myself very insulin sensitive. My insulin is like 2.5, and if I don't sleep and I am stressed and I have been sitting, my glucose will take way longer to come down.

I have become transiently insulin resistant. So I think that's just fascinating to see that. So looking-- what that ultimately-- the metric that we call that is area under the curve. You want a low area under the curve, AUC, after a glucose spike. So you want to spike and come down quickly.

That's going to-- if you shade the area under the curve, it's a small amount. If you go up and then trail off for two to three hours, that's going to be a lot of shading under that curve, and high AUC is associated with insulin resistance, basically. Another thing that you can see is essentially glycemic variability.

And glycemic variability, GV, is a metric of how spiky your curves are. Fascinating paper out of Michael Schneider's lab at Stanford in 2018 called "Glucotypes Show New Patterns of Glucose Dysregulation," totally landmark study. But basically, they put continuous glucose monitors on non-diabetic individuals who, by standard criteria of diabetes, do not have diabetes.

And he showed that on a CGM, a continuous glucose monitor, you have these low variability people that are pretty much flat throughout the day with little teeny, little teeny rolling hills after their meals. You have moderately spiky people. And then you have very spiky people who are going up, down, up, down, up, down, up, down.

When you correlate those different patterns of glycemic variability in non-diabetic people, you find that the spikier they are, the worse their biomarkers are metabolically across the board, insulin, triglycerides, et cetera. So basically, they're showing signs through variability of underlying dysfunction that you would never know from a standard test.

Those are the people who I imagine are probably going to go on to develop diseases. And yet, based on standard criteria, their doctor is telling them that they're fine, that they're all the same. So he also showed in that study that non-diabetic individuals, when you have a CGM on, are going into the diabetic range and the pre-diabetic range a fairly significant amount.

And we would never know that if you weren't actually tracking a movie of the glucose. So glycemic variability, area under the curve, those are two things. Another really interesting thing you can know from a CGM is dawn effect. So dawn effect is basically a term in the literature for how high your glucose rises right when you wake up in the morning.

I don't know if you noticed this when you were wearing a CGM, but some people notice that the second they wake up, their glucose jumps up 5, 10, 20, 30 points. What's happening here is that the cortisol awakening response to actually get you to wake up and get out of bed, that cortisol can cause you to dump a bunch of glucose from your liver.

Because it's basically saying, stress hormone, cortisol, we got to get up. We need glucose to fuel the muscles. Let's dump a little glucose. So it's normal. But what the research shows is that magnitude of dawn effect is correlated with insulin resistance. So the more the dawn effect you're getting, I think it can signal maybe the more stress you're under, the more cortisol you have floating around, how big your cortisol awakening response is.

But also, if you imagine if you're dumping all that glucose from your liver and your cells aren't taking it up well because you're insulin resistant, that response, that dawn effect is going to be higher. So I don't have the numbers right in front of me, but typically, I would want to see a dawn effect, I think, of less than 10 points.

So you wake up and you may very well see a rise. This is absence of any food yet. And you do not want to see that going up 20, 30, 40 points. Some people see a little bump again with caffeine in the morning because it's more cortisol. And so that's another thing that standard stuff would never tell you.

So those are kind of some of the looking at early predictors of metabolic dysfunction. More of the fun stuff is actually just figuring out how is food affecting your body. And this is where people really enjoy it and figure out, oh, my god, this food that I thought was healthy is actually not serving me.

And actually, a lot of people, I think, who are trying to make healthy choices-- my boyfriend, when we started dating, he started using Levels. His healthy snack, he worked in Venice, would be to go to Moon Juice and get-- oh, gosh, I don't want to throw Moon Juice under the bus here, but he would get-- They have some tasty stuff there.

They do. But he would get this green juice that was sweetened with dates, and it was $9, and this was the healthy choice. And he saw, the second he put on Levels, that it was causing a huge spike, like 50, 60, 70 points, and then he was crashing. And he was actually trying to make a good decision.

So now he's swapped his snacks out for more like grass-fed cheese and some flax crackers and maybe like a venison stick or something, like grab-and-go stuff that isn't spiking his glucose. But I think it can help people figure out which foods are doing what I want them to do and which maybe aren't.

And same thing happened for so many of our members with oatmeal. Unfortunately, instant oatmeal is one of the biggest spikers in our data set for breakfast, and a lot of people are making that choice because they think it's heart healthy. And in many people, it's actually causing a big glucose excursion and crash.

And then in some other people, it's not. And so it's really helping with, what are the sneaky spikers? And then where's the biochemical individuality? And there was a phenomenal paper out of Israel from Cell about seven years ago called Personalized Nutrition by Prediction of Glycemic Responses. It made big waves.

But it basically showed that you and I could eat the same handful of blueberries and have totally different glycemic responses. So the idea of glycemic index as like a certain amount of food with a certain amount of glucose causes a certain glucose rise, it kind of debunked that. And that matters because repeated sustained glycemic variability over time is not good for our health.

We want to choose the foods or balance the foods that are going to keep us relatively more stable. So that's very helpful, just understanding your personal response to food. And then what are the lifestyle strategies you can use-- sleeping better, walking after meals, more resistance training, cold plunging, breath work-- that can actually serve to modulate the food environment to actually reduce the glucose spikes?

And people find that all of those things can positively impact glucose spikes, especially the walks after the meals. But it's been fascinating to see a lot of women, especially like menopausal women in our community, who find that their glucose patterns are getting worse because estrogen is dropping. So that's going to really take a hit on insulin sensitivity.

They start resistance training. Glucose comes kind of right back down. So because of the monitor, they can feel more confident in the intervention they've chose to do to help with metabolism, and that kind of creates a virtuous cycle. Thank you for tuning in to the Huberman Lab Clips channel.

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