125: Blood Glucose Decoded: Insulin, Metabolic Dysfunction and Blood Glucose Monitors | DR. CASEY MEANS, MD

Episode introduction

Dr. Casey Means is a Stanford-trained physician who pivoted from head and neck surgery to functional medicine. She’s now the co-founder and Chief Medical Officer of Levels Health, a health tech startup that uses continuous glucose monitoring to empower users to make better daily decisions and improve their health. In this episode of The Neuro Experience, Dr. Means talks to host Louisa Nicola about how high blood glucose can impact our long-term health and how to keep it stable with food, sleep, and exercise. They discuss metabolic dysfunction, the role of genetics, and how continuous glucose monitors will soon become the new Fitbit.

Show Notes

Key Takeaways

07:52 – A pattern of inflammation

When Dr. Means was working as a surgeon, she saw a pattern emerging of patients coming in with issues stemming from inflammation. She started to realize that lifestyle changes could be solving these issues instead of surgery.

“You have to step back and think like, what is inflammation really? Inflammation is the body thinking that there is some threat, some foreign invader or something it has to fight and then mounting an immune response with your immune cells, which often is accompanied by swelling and tissue inflammation and things like that. And so that’s fundamentally an immune problem and surgery doesn’t really do anything to address that. So I got really focused on how can we be thinking more deeply about inflammation and helping our patients avoid this chronic inflammation that’s so tied in with so many of these ENT conditions. And then concurrently, we’re seeing how inflammation is associated with so many of the other chronic diseases that we’re seeing in our country. It’s associated with obesity and diabetes and Alzheimer’s, dementia, inflammation in the brain, and a lot of other chronic diseases. So clearly there’s something going on there. And that really led to a journey to try and understand the root causes of inflammation. And a lot of those trace right back to our diet and lifestyle.”

17:43 – How insulin resistance occurs

Insulin is released into our bodies when our glucose levels rise to help our cells use that glucose and turn it into energy, but when our blood glucose levels get too high, we can end up with insulin resistance.

“I will say that the body keeps glucose extremely tightly regulated in the body. If it’s too high, it’s a problem, and if it’s too low, it’s a problem, and you’ll have symptoms from both of those things. So when you eat glucose or foods containing quite a bit of carbohydrates, your glucose will elevate and that causes that insulin release. And when that happens over and over and over again, and the more glucose or carbohydrates you eat, the higher those elevations are going to be and the higher the insulin surge is going to be. What happens is the cells are seeing all of this insulin and they actually get numb to its effects. It’s like, you’ve been around here too much, we’re going to kind of block the signal a little bit and they get a little bit confused and that’s a process called insulin resistance. Then when that happens, your body and your cells still need to get that glucose in them. So they actually have to produce more insulin to get the same amount of glucose into the cells. So you start getting what’s called hyperinsulinemia, which is essentially high insulin levels because you’ve been spiking the glucose, you know, too frequently and cells have become numb to this insulin. What’s interesting is that when that insulin gets elevated in the blood, insulin has actually independent effects on every single cell type in the body.”

20:32 – We are eating way too much sugar

Our modern diets are very different from what they used to be.

“We’ve gotten ourselves in this tough situation where we have been exposed to just massive amounts of sugar and refined carbohydrates in our modern diets. One study I read said that we’re eating about 150 pounds of refined sugar per year, per person these days. And about a hundred years ago, we were eating about two pounds per person. So it’s just like astronomical levels. Our bodies have no idea what to do with all those sugars. And our insulin levels are just really high, higher than they should be. And you can imagine what that does. Is it when you run out of glucose, essentially, like let’s say you haven’t eaten in a few hours or you did a big exercise or, you know, overnight, you might be so hungry. Your body’s not tapping into that. It’s not able to just quickly switch over and tap into fat burning because your insulin is high and that’s called metabolic inflexibility. And that’s a state we don’t want to be in.”

24:24 – Glucose sensitivity is highly individualized

We’re learning more about what makes one person have a glucose spike from a certain food and not another person.

“There’s really interesting research that came out about five years ago and published in the journal Cell by the Weizmann Institute in Israel that was called Personalized Nutrition by Prediction of Glycaemic Responses. And what they showed is that you could feed a bunch of people standardized meals with the exact same carbohydrate composition and everyone might have a completely different glucose elevation. You and I could both eat a banana and I could go to like 170 milligrams per deciliter of glucose, a super high response, and you could go to like 95, a totally reasonable response. And so that banana is probably a better choice for you and not for me.”

31:13 – CGMs let people see real time health data

Instead of pricking your finger several times a day, a CGM can spot every spike and dip that other methods miss. That empowers people to ward off disease down the line.

“You may totally miss the post-meal spike, which may only last for, you know, five or 10 minutes and may be catching it on the upswing or the downswing and not really have an understanding of what an actual glucose response to a meal was. So it provides just massively more granularity about that. And I think a lot of people in the longevity and the metabolic health and the precision medicine space, all are very, very focused on metabolic health and how important it is for really all aspects of health and wellness and prevention of really almost every chronic disease. And so the thought is like, well, how could we maybe leverage this incredible technology and use it in people before they have sort of overt disease and help people essentially shape their diet and lifestyle to keep their glucose as stable and flat as possible to not only improve quality of life right now in your current living, because avoiding up and down spikes, even if you’re otherwise normal and healthy is hugely advantageous for just current day-to-day life, especially in regard to cognitive performance and mental health and energy.”

35:26 – How long should you wear it?

Dr. Means says even one day can give you a lot of insight, though longer is better for establishing patterns.

“I think wearing it for longer is excellent, but I actually find that getting averages even for 24 hour periods can be incredibly interesting. So what I’ve found, I’ve been wearing it for about a year and what I’ve found is that based on what’s going on in my life and whether I’m traveling and how stressful things are and whether I’m really on point with all of my wellness practices, my daily 24 hour average glucose can bounce around by like 10 points. I can be 75, which would be on the really good end for me for 24 hour average glucose, or I can be up in the mid to high eighties just depending on whether I’m doing what I know keeps me in my healthiest range. And so it’s actually really fascinating to see how dynamic it is. And I think what it does, is it just really solidifies this point that like what I’m doing and how I’m living like is the differentiating factor between the two different outcomes of a high average or a low average. And so it’s very motivating. And I use it to basically keep me on track. Like at this point, the insights I’ve learned from it, what I should be eating, how I should be pairing foods, when I should be eating foods, what exercises are best for my metabolic health? What stress management practices keep my glucose low, how sleep impacts it, etc.”

40:50 – Redefining healthy glucose levels

The Levels team set out to find the true healthy range because the standard medical ranges are about identifying disease and not optimizing health. Levels defines the optimum range as between 70 and 110.

“One of my first things that I did when we started levels was, I was like, we’re going to double down on light. Let’s look at all the research, what is actually healthy glucose levels and okay, we’re going to come up with the ranges that really fit with the research about what it means to be in the optimal glucose ranges. And so there’s around six or seven large studies where they’ve put CGMs on healthy non-diabetic populations and just like trashed their glucose over time to get a sense of what is just a healthy person’s glucose levels? What is it normally on a 24 hour day? That stuff, it was never possible to do that type of study before CGMs were around. So thank goodness some research labs had the foresight to put these on non-diabetic people and actually get that data. And what that shows, and I’m going to kind of summarize it, but that person who is non-diabetic and otherwise healthy, they spend about 91% of the day between glucose ranges of 70 and 120. So only about 9% of the day below 70 or above 120. Couple other studies that are more lenient about the population and have some bigger population show that it’s actually people spend about 90% of the day between 70 and 140. But the bottom line is people should probably rarely if ever go above 140, if you’re non-diabetic.”

45:44 – Stress increases blood glucose levels

Evolutionarily this was a good thing if we were being chased by a lion, but we’re no longer using those glucose spikes in the same way.

“You will find that people who are dealing with physical stress, psychological stress, or just, perceived stress, that you can see a glucose elevation and we’ve, I’ve seen that in myself. We’ve seen it in a lot of our early customers. It’s seen in the research literature. And so it’s very interesting. It’s like an evolutionary sort of advantage that now has kind of gone awry in our current lifestyle. So to have a lot of low grade sort of chronic stressors that don’t require us to need more glucose in our bloodstream because they’re not requiring us to do any physical activity. You know, it might just be like a stressful email or a stressful conversation with a colleague or something like that. Or like even anticipation of a stressful event, like anxiety and these things can get your body through that cortisol signal to release glucose for essentially a reason that we don’t need any more.”

54:51 – Food context is key

For example, Dr. Means said that linoleic acid can be problematic when it’s consumed in refined, packaged forms, but not in whole plants.

“It’s like these new exposures for our bodies that we were never meant to be exposed to. Every single processed food package that you pick up in the store has some type of refined oil in it. Canola, safflower, sunflower, corn, whatever. So, it’s kind of in everything. It’s in salad dressings, it’s in crackers, it’s in breads. And so we’re just getting these massive exposures. Is that the same as saying that eating some whole foods and vegetables that are packaged with thousands of phytochemicals, many of which are antioxidants and that can buffer free radicals, that that’s the same as eating, you know, a ton of refined oxidized, sunflower oil per day? It’s totally different. It’s a completely different conversation. And it’s really easy, I think to say like, Oh, it’s all the same. It’s all linoleic acid, but I don’t think that’s true. I think that foods packaged in their whole food form, which nature created to be packaged with a lot of things that actually buffer some of the problematic aspects of the molecular information and food is one thing. And then the refined version that essentially just takes the harmful part and puts it in super high concentrations in the body is a totally different question. So I think food has to really be thought about in context.”

57:35 – Exercise and glucose

A study showed regular movement has the greatest impact on blood glucose levels.

“There was some interesting research as well that showed, they took three groups and they basically said, okay, one group is going to walk for 20 minutes before each meal three meals a day. So a total of 60 minutes, but 20 minutes before each meal or 20 minutes after each meal. Or walk for two minutes, every 30 minutes for the entire waking day. All of that added up to 60 minutes total of walking and the group that actually had the lowest 24 hour glucose levels was the group that walked for two minutes, every 30 minutes throughout the day. All of them did better than people who didn’t walk, of course. And so the bottom line is like, do anything. People should move.”

1:01:55 – Behavior change software

Dr. Means said that the future of Levels and CGM is allowing all types of people to take advantage of this type of behavior change software for better health.

“What’s so neat about our product and Levels is that fundamentally, this is a behavior change software. This is about inspiring people with their personal data to make better choices and making it really painless to understand what works and then move the needle on moving in the right direction and build really comprehensive, metabolic awareness about how to keep that glucose line flat and stable. And we know when that glucose line is flat and stable, that outcomes are much better for all aspects of health. And so I think in time, we all know, Oh, you should eat, you should walk 10,000 steps a day and you should get eight hours of sleep. And I think people will be talking about glucose like that saying, well, yeah, we all know that we need to keep our glucose lines flat and stable and it will be similar in that regard to those other trackers.”