- How is it that what we eat impacts our glucose response? And maybe you could tell us a little bit about what a healthy glucose response looks like. Because by most people's view, any inflection in blood glucose is a quote unquote spike. But what are the sorts of spikes that matter for health?

And what are the sorts of spikes in blood glucose or what are called the glucose excursions that, you know, okay, well, that's a normal response to eating some food. And then it goes back down to baseline. I think this is especially important nowadays with all the interest in metabolic health, in how particular types of foods like processed foods are indeed far worse for us and on and on.

So if you could just give us your view and understanding of glucose excursions, what they mean, when they're good, when they're bad. - Well, I would say that, you know, high, long, prolonged spikes is obviously pretty bad. But certain things, like if you eat a grape, grape's pretty loaded with sugar, but it's a pretty transient spike.

It'll go up. And so that would be a transient one. And actually, when you do strength training, for example, for exercise, you break down glucagon, which is a, you know, it's a polymer of sugar that you break down, gives you energy. That's important for when you're doing exercise and training.

And that will give a glucose spike. I get a glucose spike every morning when I weight train. So that would be a normal, healthy one, but it's transient. It goes away pretty quickly. - What's quickly? - Within 30 minutes, maybe most 60 minutes. Now I'm a special case, I'm a type two diabetic.

So my spikes go higher and longer than most people. So yeah, mine are not good spikes, but we can get into that. So what is a good spike? Well, the calibration people mostly uses time and range. It's a simple metric, meaning if you're a healthy person, your glucose is normally, for most people, around 90.

And if you're off, you will go higher than that. For most people, you want to keep your glucose between 70 and 140. If you're healthy, for diabetics, they say, try and keep it between 70 and 180. And that is what people try to do. And most healthy people, it's pretty easy.

And I think one of the things we've done, you've heard about continuous glucose monitors, these devices, and I'm wearing one, and some of your staff, I know, are wearing them as well. And they're over the counter now. You put these on your arm, and they measure your glucose every five minutes, so you can see exactly what's going on.

And so we put them on so-called normal people, pre-diabetics, and some diabetics. That was already well-known. Diabetics will spike their glucose through the roof, too high for too long. And then the people devise, especially type 1s, control mechanisms for releasing insulin, controlling all of that. But for the average person, that wasn't so well-known at the time we were doing this.

And it was a bit of a surprise to see that a lot of people-- some did a very good glucose control, but some pre-diabetics were what we call moderate spikers. We came up and named glucotypes as a way of quantifying this. And then some people were spiking just as bad as diabetics and had no idea.

And so it was a way of revealing what was going on. So it's recommended that you try to stay in this 71-40, but it is a bit arbitrary. But it's not a bad rule of thumb to work by for the average person. But again, some people have very, very good glucose control.

Some are moderate spikers and some are severe. And it's pretty clear that excessive spiking, especially in diabetics, is associated with cardiovascular disease and other things. There are some pretty strong papers out there on that. So you do want to keep it under control. And there's a very strong correlation between this time and range measurement I mentioned and something called hemoglobin A1c.

That's a measure of your steady-state glucose. And so if you have high hemoglobin A1c, that's typically how we classify people for diabetes and pre-diabetes. If you're over 6'5" or over, you're classified as diabetic. If you're 5'7" to 6'4", you're pre-diabetic. And if you're under that, you're so-called normal. And this time and range will actually correlate very, very well with that.

So it's a surrogate measure for that. But it's actually pretty cool because you can precisely see what's going on in real time, unlike a hemoglobin A1c measurement, which you get periodically. So if you want to dig into that further, I would say that, you know, what's cool about these CGMs is that you wear them, like I'm wearing one now.

You can wear them for about 14 days, depends on the particular device. And you see exactly what foods do what to you, and we're all different. So some people spike to bananas, some to potatoes, some to pasta, some to white bread, some to brown bread. And so this was shown by Aaron Siegel's lab at the Weissman, and our lab had found something similar.

And it's very personal. And so we've been spending a lot of time trying to dig into what's behind that. So different people's glucose spike to different foods. It's hard to predict on the basis of something like a chart of glycemic index, for instance. So if I understand correctly, and I have glanced at those papers, you know, I might be able to eat mango with nothing else, and my blood glucose doesn't go out of range, or at least not for very long.

Whereas somebody else might have a very big and prolonged spike in blood glucose to mango. But maybe there are things they can eat that I can't eat, like, I don't know, sourdough bread or something. By the way, I can eat sourdough bread. But just by way of example. A hundred percent, yeah.

Yeah. And so really the only way to know, as you're pointing out, is to measure. I want to talk a lot about measurement today. All right. For those that are just listening, not watching, Mike is wearing many sensors. How many sensors? You have got four watches. And my ring and even my hearing aids are sensors, believe it or not.

So, they are for hearing, but, uh. We're going to get into all of that, but maybe we could talk a little bit about some of the subjective experience of blood glucose excursions, both healthy and unhealthy. Okay. Most people are familiar with eating a big meal, like the, you know, the cliche is the, you know, the Thanksgiving meal after which you're tired, where you stuffed yourself with protein and carbohydrates and dessert, et cetera, maybe some alcohol too, in some cases.

But I think people are also familiar with, you know, eating a certain food. Like for me lately, I'll have my bowl of oatmeal with some berries and my protein drink after I train. And I'm noticing with each successive year, I'm getting really sleepy after I eat this. And I've swapped out the oatmeal for a different carbohydrate recently, just some white rice, and I feel fine.

And I don't think this is my imagination. I mean, in one case, I want to take a nap afterwards. In the other case, I'm good to keep going and I generally have a lot of energy. So, is what I just described atypical, what are some subjective effects of high glucose spikes?

Yeah. Well, certainly, uh, sleepiness is one. I can put myself to sleep with a piece of pizza. Um, I'm diabetic. I'm a unusual diabetic. We can talk about that too. Uh, and yeah, if I eat pizza, my glucose goes through the roof and, um, I will get sleepy. So does that mean that you eat and you feel sleepy?

Or there's a, uh, a period after you eat, because this is what I experienced, where I feel very energized for a short while, and then it's almost like my vision gets a little blurry and I feel kind of like, um, yeah, like I just want to curl up and take a nap, even if I slept great the night before.

Is that a blood glucose response? I believe so. I mean, there are multiple things that affect sleepiness and you probably know this better than me since, uh, you've covered sleep more. But, um, yeah, like tryptothanes, things like this can help induce sleep as well, but certainly glucose, these large glucose spikes, uh, I can say personally make me very, very sleepy.

Uh, and alcohol can make a lot of people sleepy too, but you're right. There can be a lag because that first little shot of glucose can be a stimulant, um, but, uh, very soon that shot can go very, very large, uh, of glucose and, at least for me, it makes me very, very sleepy.

So, I think it's very normal. So, I think it's very normal.