Editor’s Note: In this conversation from Huberman Lab podcast, Dr. Andrew Huberman and genomics expert Dr. Michael Snyder discuss how different foods uniquely impact our blood sugar and what constitutes a healthy glucose response. They explore the use of continuous glucose monitors (CGMs) to map personalized “glucotypes,” highlighting how individual bodies react differently to the exact same carbohydrates. The discussion also touches on the practical, everyday signs of glucose spikes, such as the sudden post-meal fatigue or “food coma” that many people experience.
Understanding Glucose Excursions: What’s Normal and What’s Not
DR. ANDREW HUBERMAN: 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 glucose excursions, that you go, “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.
DR. MICHAEL SNYDER: Well, I would say that 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.
Actually, when you do strength training, for example, for exercise, you break down glucagon, which is 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.
DR. ANDREW HUBERMAN: What’s quickly?
Time in Range: A Key Metric for Glucose Health
DR. MICHAEL SNYDER: Within 30 minutes, maybe most 60 minutes. Now I’m a special case, I’m a type 2 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 use is 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 5 minutes so you can see exactly what’s going on.
And so we put them on so-called normal people, prediabetics, and some diabetics. That was already well known. Diabetics will spike their glucose through the roof, too high for too long, and then people devise, especially type 1s, control mechanisms for releasing insulin and 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 have very good glucose control, but some prediabetics were what we call moderate spikers. We came up with the name 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 70 to 140, 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 prediabetes. If you’re 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 in 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 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 is shown by Aaron Siegel’s lab at the Weizmann, and our lab had found something similar, and it’s very personal.