Ep. 132 – Continuous Glucose Monitors: Why They’re Not Just for Diabetics Anymore with Kara Collier

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We are excited today to have Kara Collier joining us as our guest. Kara is a Registered Dietitian Nutritionist and Certified Nutrition Support Clinician with a background in clinical nutrition, nutrition technology, and entrepreneurship. After becoming frustrated with the traditional healthcare system, Kara helped start the company NutriSense, where she is now the Director of Nutrition. She is the leading authority on the use of continuous glucose monitoring (CGM) technology, particularly in non-diabetics for health optimization, disease prevention, and reversing metabolic dysfunction. Kara oversees the health team and product development and has personally interpreted thousands of complex glucose datasets.

Part of Kara’s frustration with the Western medical mindset is that in a hospital or clinical setting, the priority is usually to medicate and treat people as quickly as possible and then get them out. People are in and out of the hospital all the time, and they are suffering because the root cause of their problem, which is usually their lifestyle, is not getting addressed. In this episode, Kara talks about blood sugar levels and explains why CGMs (continuous glucose monitors) are useful for everyone and not just diabetics. Be sure to stay tuned to learn how food influences your blood sugar and how you can make the best nutritional choices for your health and wellness. 

“I dug into the research about what is driving all of these problems, and it all points to metabolic health and insulin resistance.”

Kara Collier


  • Kara explains what it was about the traditional Western medicine mindset related to food and nutrition that prompted her to second guess what she was doing.
  • Kara defines normal in terms of what we would ideally like to see for a fasting glucose level.
  • What people need to be concerned about regarding their hemoglobin A1C.
  • Kara discusses where she prefers to see the ranges for fasting insulin.
  • Some of the things that can influence someone’s postprandial reading.
  • Kara explains what happens in our bodies when our blood sugar values are not where they should be.
  • Kara discusses what she is seeing in terms of the impact on glucose from certain types of diets, like keto and vegan.
  • The differences between men and women.
  • What a CGM is.
  • Why should everyone wear a CGM, not just diabetics.
  • How different types of exercise impact your blood sugar values.
  • The benefits of fasting and the impact of fasting on your blood sugar.

Connect with Kara

On the NutriSense website 

Connect with Cynthia Thurlow

About Everyday Wellness Podcast

Everyday Wellness is not just another health podcast. Your host, Cynthia Thurlow (nurse practitioner and nutrition/IF expert) has over 20 years of experience in clinical medicine and wellness. Her mission is to bring you the best, science-backed yet practical information to improve your physical and mental wellness every day. She is a busy mompreneur and knows how important your time is. She has designed this podcast to be short in time and big on impact. She interviews a variety of guests in the field of health and wellness, and discusses important issues, and provide practical strategies that you can use in your real life.


Presenter: This is Everyday Wellness, a podcast dedicated to helping you achieve your health and wellness goals, and provide practical strategies that you can use in your real life. And now, here’s your host, Nurse Practitioner Cynthia Thurlow.


Cynthia Thurlow: Today, I am so excited to have Kara Collier. She’s a registered dietitian and nutritionist and certified nutrition support clinician with a background in clinical nutrition, nutrition technology, and entrepreneurship. After becoming frustrated with the traditional health care system, something everyone that follows me understands, I did as well, she helped start the company NutriSense, where she is now the Director of Nutrition. Kara is the leading authority on the use of continuous glucose monitoring, CGMs. A technology, particularly in nondiabetics, for the purposes of health optimization, disease prevention, and reversing metabolic dysfunction. Kara oversees the health team and product development and has personally interpreted thousands of complex glucose data sets. Welcome, I’m so excited to have you today.

Kara Collier: Thanks for having me. I’m excited to be here.

Cynthia Thurlow: Yeah. It’s interesting, I saw you on multiple people’s podcasts, and I kept thinking there’s something to this. As I dove down this rabbit hole, it really occurred to me that CGMs are not just for diabetics, and obviously, I’m from a traditional western medicine training, but also have functional training. The more that people understand how our food influences our blood sugar, the more they will understand, it’s not just people walking around saying carbs are bad, or you can never have dessert or a glass of wine, but when you can see that information in real time, it can reinforce or discourage people from continuing to make the same choices. So, I know that you started in clinical nutrition. I know we probably are very aligned on this, what was it about the traditional kind of western medicine mindset about food and nutrition that really started to cause you to second guess what you were doing, the environment that you worked in?

Kara Collier: Yeah, and there’s certainly multiple components to it. We can have a whole podcast on this topic, but I’ll try to keep it brief. Part of the frustration was, in a hospital setting, in a clinical setting, it’s get them out as fast as possible, put a band aid on it, add a medication, whatever treatment we need to do so we can get you out. Which is good, we don’t want people in the hospital longer than they need to be. But then, there’s a disconnect with communication and follow up to provide the appropriate care, that person needs to not come back to the hospital. What I’m sure you saw is, you see these frequent fliers, people are just in and out of the hospital all the time, because we’re never ever addressing the root cause, which is often lifestyle. And that’s just really not touched on, and so it’s frustrating, because you see all this suffering. This unnecessary amount of procedures and medications and pain that people are going through, when really we could have prevented all of that, or at least minimized it by talking about lifestyle. 

The other frustrating component is when you finally do get to have that lifestyle conversation, some of the traditional recommendations are not actually that helpful. I’m a registered dietitian, I also was trained traditionally, and some of the recommendations, which maybe are meant well, maybe are not, who knows what’s going on behind closed doors, but they didn’t necessarily help people. So, standard recommendations to eat 45% to 65% of calories from carbohydrates, have small frequent meals, these recommendations were not moving the needle. Once you have chronic conditions, multiple chronic conditions, you have to make even more extreme measures to address it and to fix it. These just weren’t cutting it. 

I was frustrated with the lack of conversations around nutrition and addressing the root cause. Then, I was also frustrated with the nutrition recommendations I was taught that I could see were not working, when I did have someone who was finally motivated and excited to address the root causes of their problem. Then, it was like, “Well, they lost their excitement because they’re not seeing any progress or improvement.” From that, I was like, “Well, we have to start somewhere else.” And so, really dug into the research about, what is driving all of these problems? It all points to metabolic health and insulin resistance. They’re all connected. That’s why most people don’t just have one chronic condition. Eventually, they get multiple because it’s all connected.

Really, at the heart of that is glucose. There’s other metrics involved, but I like to think of glucose as sort of like the 80/20 best bang for your buck when it comes to metabolic health because it’s easy to measure and it tells us a lot. It’s not just telling us how many carbohydrates you’re eating, which of course, increases or decreases glucose levels but it’s also impacted by sleep, and stress and exercise and fasting, when you’re eating, the circadian rhythm, all of these factors that are so important for holistic health. Glucose plays a role in that. 

When we look at people’s glucose levels, we get such a good view of what’s going on, and maybe where the problem areas really are that we need to dive into. I think you made a really good point that it is personalized too. Some people thrive on a higher carbohydrate diet, and that’s great, and a lot of people don’t. We have to know what’s your unique situation, your combination of genetics and epigenetics and the life you’ve lived that far? Where are you at right now, and what’s best for your body? We don’t know that unless we’re measuring some sort of data to tell us where to go. There is not one-size-fits-all approach or diet. I’m sure that you agree with that as well. And that’s why I think data is also really helpful because it can make something very personalized, which is also more motivating for the customer or the patient because they know this is how my body responds, and I’m much more driven to stick with that plan or stick with that goal I set because I know how meaningful it is. It’s not just like a generic thing somebody told me that I’m like maybe it’s working, maybe it’s not, you know because you can see the data.

Cynthia Thurlow: I think that’s such an important point, that objectivity, because it’s one thing if we as clinicians are making recommendations, and then someone has to go home and implement changes that we’ve suggested, but if they on their own are able to look at the information and say, “Oh, okay, I clearly overdid it with the” insert whatever it is, Thanksgiving, holidays, we’re probably not doing as much celebrating in 2020. Or, if we’re doing it, we’re doing in the privacy of our own homes. But having that ability to reflect on the choices that we’ve made and say, “Okay, I need to ratchet things in because my CGM data,” again, continuous glucose monitoring, “is not where it should be.” Let’s define normal so that people understand what objectively are we looking for? What do we ideally want to see for a fasting glucose? When I think about fasting, I think usually a lot longer than 8 hours, but I used to tell my patients, 8 hours is a good reasonable, but probably closer to 12. So, if we’re looking at a fasting glucose level, what would you ideally like to see?

Kara Collier: Yeah, so in a fasted state, yeah, technically defined as at least eight hours without food, we want to see that between 70 and 90. With the caveat that some non-diabetics who are perfectly healthy, especially somebody on a ketogenic diet or a very low carb diet, they might actually have a fasting glucose less than 70. And if you have no symptoms, no dizziness, lightheadedness, that’s perfectly fine. But traditional recommendations would say anything below 100 is okay. But there’s quite a bit of evidence to suggest that buffer zone of 90 to 100 is an independent risk factor. So, that’s kind of a yellow flag in my mind, of not prediabetes technically, but things are maybe starting to go awry. 

Fasting glucose values could be temporarily increased. Also, that’s why CGM is helpful because we’re not just looking at this one snapshot in time annually at your fasting glucose level, we get to see every day, every morning what does it look like. Because sometimes if you get a bad night of sleep, that number is going to be way high. Or, if you’re super stressed, because something’s going on. Or, if you’re sick, if you have COVID, or if you have flu or something. So, we’re looking at given the circumstance, but if you’re not sleeping every day, and you’re stressed every day, and it’s perpetually elevated, that’s obviously more of a chronic problem we need to address. But technically, 70 to 90 is the sweet spot I’m looking for in a fasted glucose.

Cynthia Thurlow: It’s interesting, I’m laughing because one of my doodles is starting to bark. So, hopefully he’s going to be quiet. 

Kara Collier: [laughs] 

Cynthia Thurlow: I know that some of the study research I’ve looked at has indicated that if you get less than six hours a night of sleep, and I know there are plenty of you listening that probably do that and think it’s no big deal, you reduce your ability to control your blood sugar by anywhere from 50% to 60%. I actually had Dr. Kirk Parsley on a few weeks ago. He was saying that, on average, if you get less than eight hours a night of sleep over the course of a year, that can actually influence your weight gain by, I think, he said 14.3 pounds, which for anyone that’s listening, I don’t want to be 14.3 pounds heavier this time next year. Sleep is really, really important. I think it’s so, so helpful for you to getting back to glucose, kind of defining what is normal so that people understand knowledge is power. This is really going to date me, but when I went through my nurse practitioner program and finished in 2000, which was a long time ago, we were looking at numbers under 140. It tells you like we’re getting better at identifying people that are at risk and what the normals are, but we’ve still got room to go.

When we’re looking at other types of labs, and I know we kind of touched on this before we started recording, I had mentioned fasting insulin as being one of those first kind of indicators. But what I found most interesting, Kara, was when I was listening to you on another podcast, when you were talking about hemoglobin A1c, can you share with our listeners? Because I think most of us are thinking, “As long as my hemoglobin A1C and fasting insulin look good, I’m good.” But you’re suggesting and this sounds completely reasonable, that isn’t really the case. What do people need to be concerned about?

Kara Collier: Yeah, absolutely. Hemoglobin A1c, I think, has in a mainstream audience gotten perception as being the gold standard if I have diabetes, or not, and it is used to diagnose diabetes, but it has a lot of flaws. I think just like you said 20 years ago, we were looking at fasting glucose of 140, now we’ve adjusted that to 100, I guarantee you in 5-10 years of that thresholds going to be at 90. I think, eventually people will move away from A1c as well, because of the evidence that’s coming out about it. One thing that’s important to know is what is it actually measuring, people think like, “This means diabetes or not.” But really what it’s doing, it’s measuring how much sugar is on your hemoglobin molecule. It’s like when we have blood sugar circulating in our system, it glycates proteins, it makes it sticky.

A hemoglobin molecule is on your red blood cell, and an average red blood cell lives for 90 days. What a hemoglobin A1c is telling us, is how your average glucose values have looked over the last 90 days, three months. So, inherently, what it’s measuring is slightly not that useful, because it’s telling us an average. An average is interesting, but it’s missing any sort of variability. You could be spiking to 200, which is really high and crashing to 60, and having reactive hypoglycemia and all types of trouble with your blood sugar levels, but the average could be right at a nice sweet spot, and you wouldn’t catch that at all in an A1c value. That’s really the first flaw in my view. The research says that those spikes and that swings in your glucose values, the glycemic variability is actually the most important measures to be looking at to predict diabetes and insulin resistance and cardiovascular disease. We want to look at those metrics. 

The other reason it’s unreliable is because it’s making the assumption that your red blood cell lives for 90 days, which for a lot of people is not actually true. Anemia, which is extremely common, alters the lifespan of your red blood cells. Even high glucose values, if you have diabetes, alters the lifespan of your red blood cells. Blood loss, smoking, B12 deficiency, low carb ketogenic diets, all of these can skew the lifespan of your red blood cells, which can either make it a false positive or a false negative. And they have researched this and it’s only about a 50% sensitivity to perfectly match with actual average glucose values. So, that’s not great. In general, I say hemoglobin A1c is good for a proxy measure. Normal is below 5.7%. So, if you come back with a 10% value, that’s high. No amount of skewed red blood cell life is compensating for that. So, that tells us something. 

Another is for personal tracking. If you get it every year, and it goes from 7 to 6 to 5, and you haven’t changed anything with anemia, or any of these other contraindications, then you can at least track your progress, it’s going in the right direction. And that’s where I see the use case of the hemoglobin A1c is for those two applications, like extreme outliers, and then just personal trends tracking. But I have a lot of people who come to me and they’re like, “My A1c is 5.9%, and I’m freaking out,” and their CGM data is amazing. I’m like, “Well, that tells us so much more.” I just think there’s this misconception that hemoglobin A1c is a gold standard, so that’s really the message I’m trying to get out, is that it has its flaws.

Cynthia Thurlow: I think that’s really valuable because I know that there are many of us that evolve, shift, and change as clinicians, and then there are some people that aren’t as good about that. I know the one thing that I’ve been consistently telling my female patients is, “Let’s focus on that fasting insulin,” because we know sometimes that is oftentimes the first thing that will start to shift as you are becoming insulin resistant. Interestingly enough, last time, I had mine drawn, my nurse-midwife said, “I think this might be the lowest insulin level I’ve ever seen.” I was like, “Well, what does that mean?” She said, “Well, I don’t think I’ve ever seen it be 2.1.” And then I go on to find out that it’s not that unusual. It’s not as if I’m dead. But it just means that there’s more metabolic flexibility and that’s really what we’re looking for. A fasting insulin is not a weird or unusual test, it is a fairly common test, but you just have to have your healthcare provider order it. Where do you like to see your ranges for that, you get differing opinions? I’m curious to know what your kind of standard is.

Kara Collier: Yeah. For our customers that are really focused on prevention, optimal metabolic health, and they don’t have diabetes, I really like to see it 2 to 5, which is probably the tighter, more strict range. If we’re working on progress, anything closer to that range is a win. Traditional reference range, I think, is something crazy, like 5 to 20 or something like that. That’s another caveat for those who don’t know. I’m sure you’ve said this before that reference ranges are not always what you want to look at as well. That’s just a standard deviation of whatever that lab uses and their population, and the average person is not that healthy, so we don’t necessarily want to be in the average, sometimes we want to be in a different optimal range. But 2 to 5 is what I look for. We’re not a clinic, so we’re not ordering labs, but we highly encourage people to get a fasting insulin because it can tell us a lot, and it’s very complimentary to CGM data. 

Something that I think is useful with CGM data as well is, it’s really hard to get a postprandial insulin value done. Fasting insulin is awesome, just like fasting glucose is awesome, but both of those values only tell us what’s happening in a fasted state. Some people can have a low fasting insulin, a low fasting glucose, and then maybe you give them a glucose challenge and their postprandial insulin, so how much their body releases in a fed state is really abnormally high. That’s hard to measure, most labs are not going to do that. You can do like an oral glucose tolerance test with insulin, but it’s just not very common. But if you do a glucose challenge, glucose tolerance test, while wearing a CGM, that postprandial shape, your glucose response to that meal, is a very good proxy for how much postprandial insulin your body needed, especially that area under the curve. So, how big that glucose response is, were requiring insulin that whole time. So, that’s why I think it’s very complimentary to know both of those pieces of the puzzle. 

Cynthia Thurlow: When we’re talking about postprandial, if people aren’t familiar with that terminology, it just means post meal. For any of us that have been pregnant, you probably have been subjected to the horrible glucose tolerance test. For anyone that doesn’t like really sweet things, you’re subjected to this load of– I don’t even know how many grams of sugar a–

Kara Collier: It’s usually 75 grams, which is quite a bit.

Cynthia Thurlow: Which is miserable, and then you get your blood taken multiple times. But for purposes of talking through with the group, what are some of the things that can influence that postprandial reading? Whether or not it’s done if you’re sitting in a lab, and you’re having labs drawn at one hour, two hour, four hours post consumption of this glucose load, what are some of the things that can influence that?

Kara Collier: Yeah, so how high your response goes, versus if it’s normal? An OGTT, oral glucose tolerance test, is actually one of the better measures for assessing insulin sensitivity and insulin resistance. It’s not done that often unless you’re pregnant. In the general population, unfortunately, it’s rare. But this is one of the few moments that we can capture that maximum glucose value, like how high does your glucose spike? That’s not really captured in any other traditional metric. Hemoglobin A1c is the average, fasting glucose is fasted. When you’re wearing CGM, whether you’re doing 75 grams of glucose or you’re eating eggs and sweet potatoes, we want to see how high does your glucose go, because that’s also an important metric, even though it’s missed in traditional settings. 

Typically, if you’re eating just normal food, and you’re not throwing a ton of glucose at your system, we want to see that maximum glucose value below 140 most of the time, so this is really about repetition. I like to make it clear that if you hit 140 once, your system isn’t going to crumble and fall apart. It’s about making sure that’s not part of our daily routine. Your go-to breakfast isn’t spiking you to 140. That’s a problem. We want to adjust those things. If you were doing a 75-gram glucose tolerance test, we don’t want to see it ever spike above that 180 mark. Above that, in my view, is starting to be a problem. Both with a large glucose load or smaller one that you might be having on a meal, we want to see that come back down to pre-meal glucose values fairly quickly. Usually within two to three hours, but if you look at data on those oral glucose tolerance tests and they categorize it normal glucose tolerance, impaired, or diabetic, the normal glucose tolerance, they keep in that first 30 minutes, and then they’re already coming down and at two hours, we’re back down to where we started. So, that’s a nice healthy response. Whereas impaired, not quite diabetes, maybe prediabetes, early signs of insulin resistance, we spike more at the hour mark, maybe hour and a half, and takes a little bit longer. Then, with diabetes, we spike really high and we stay up high for a while. So, it’s just amplified beyond that. 

We’re looking for similar things in just your day-to-day meals as well. How quickly did you come back down? I’d rather see you kind of go up and then recover quickly, that shows me that your cells are sensitive to the signal from insulin. It got the signal, and it knew what to do with it, and it recovered glucose, that’s a healthy metabolic system. Whereas, if glucose is staying high for a really long time, especially from something not that crazy, maybe half a sweet potato or one slice of bread, your glucose is staying high for a long time, that’s a red flag. I say that as a caveat, even healthy systems myself, if you do something that’s a lot of carbohydrates, and a lot of fat, like pizza or fried food or creamy pasta, any of those things, even a healthy insulin-sensitive person is going to see a long, prolonged glucose response because you just overloaded your system with fat and carbs, and fat slows down that digestion and your carbs are running through your system for a long time. So, you see that you’re not necessarily insulin resistant, you just probably didn’t make the best food choice.

Cynthia Thurlow: I think those macros are really important. I know even with fasting, we talk to patients about not breaking your fast with something that’s carb heavy, that it’s the time to have some light protein, it’s the time to have some fermented foods. Really ensuring that you’re not breaking your fast with just carbohydrates, because we know that’s going to secrete more insulin to try to keep the blood sugar low. So, let’s kind of pivot and talk a little bit about, what happens in our bodies when our blood sugar values are not where they should be? Obviously, if we look at the bulk of the population, we know that most people are not metabolically healthy, they’re overweight, they’re obese. I call it diabesity, that so many of the population now is really metabolically not very healthy. What happens to our bodies? What are the things that start to happen that obviously are not beneficial, but I think it’s important for people to fully understand that before we walk through the CGM in ways to kind of address this?

Kara Collier: Yeah, absolutely. Real quick note on breaking the fast. I 100% agree, I cannot emphasize that enough. This was something where it’s like, “Oh, I had heard that’s important.” And then you see the date, and you’re like it’s really, really important. A daily fast and especially longer fast, no carbs and not breaking the fast or else it’s going to really reverse all the good you just did. But thinking about consequences of these abnormal glucose values. If you’re not diabetic, it’s like why should we care? Really, the damage is done on both the microvasculature and the macrovasculature. If we first take a zoomed-in look at what’s happening at the cellular level, a lot of what’s going on is stress on the mitochondria. Mitochondria in our cells, they don’t get enough credit, they do a lot, and they are really the site for all of these metabolic reactions. They’re processing the energy you’re putting in to try to make usable energy. 

When we flood the system with a lot of glucose, which is our quick, immediate energy, it puts a lot of stress on the cell and on the mitochondria, and it’s basically putting the gas pedal all the way down. It’s going to process that energy, because that’s its job, but it’s having a lot of energy to process and it’s overwhelmed, which can produce free radicals and cause oxidative damage. If you do this, every once in a while, you have more carbs than normal on Thanksgiving or your birthday, it’s not a big deal. We have systems in place to clean up that oxidative damage, clear out the free radicals. But if you’re doing it every day, then we start to get in a cycle where the damage is more than the cleanup. The short-term damage can’t be fixed and reversed because we’re damaging it again before the body has fixed it. A lot of this has to go with inflammation and oxidative damage, which we all know inflammation is a serious problem, especially if it’s on a chronic basis.

And then, those glucose spikes themselves. They are independently dangerous to our blood vessels. We’re meant to have a system that only has so much glucose in our bloodstream at any given point in time. Our bodies work really, really hard to keep that in a very specific range. When we spike that higher, like if you have a spike up to 180 or 200, then that can damage our endothelial cells of our blood vessels and cause an inflammatory reaction there as well. That’s where atherosclerosis, cardiovascular disease really plays a part of diabetes, because it’s damaging the blood vessel, and then it’s causing some inflammation so we can heal it. Then, that repeated abuse is a cycle that we don’t want to enter. 

That’s where if we have this combination of oxidative stress, inflammation, damaged endothelial cells, we get into this feedback loop of damage, and you’re also calling on a lot of insulin every time you are stimulating glucose. It becomes this boy-who-cried-wolf-type of situation, where you need insulin every once in a while, it’s doing its job, insulin, super, super important. But if you’re calling on it every two hours, when you eat maybe a high carb meal five or six times a day, eventually, your cells start to ignore that signal, and we can get into that feedback loop of insulin resistance at the cellular level where it’s starting to ignore the message, so the body pumps out even more insulin to compensate. Eventually, it’s just not enough, and that’s insulin resistance, with inflammation with cardiovascular disease. All of that takes decades, which is why I’m really passionate about fixing it early, and getting these devices on people when they feel healthy, and they feel fine so that we can identify, these are your daily trends, and this is where we need to adjust something, so that we don’t get stuck in that feedback loop that leads to diabetes and heart disease and kidney disease. That’s in a nutshell, not to sound too scary, but it takes decades, so we can fix that all if we catch it.

Cynthia Thurlow: I think it’s important for people to have a sense of what happens when we don’t, or we don’t allow ourselves to be concerned about the choices that we’re making. I’m a huge advocate, as I know you are, about the preventative side of things. I’m just curious, when we’re looking at nutritional kind of mindsets and philosophies, are you seeing– I know there’s lots of schools of thought right now, we’ve got carnivore and keto and low carb and paleo and vegan. Obviously, it goes back to bio-individuality. But are you seeing that it’s skewed one way or another that there’s a more of a nominal impact on glucose with particular kinds of diets? If people are eating a whole foods kind of nutrient dense diet as opposed to a lot of process, because in every camp– maybe not carnivore, but in nearly every camp that I just talked about, there is junk food. There’s vegan junk food, there’s keto junk food, it’s all there. So, just because it has a you know, a tag on it that says it’s keto or carnivore or what have you, it doesn’t necessarily mean it’s healthy. But are you seeing certain nutritional philosophies that have a more negligible impact on blood glucose?

Kara Collier: Yeah, and you touched on the biggest role, which is whole foods that have to be whole foods. Whole wheat flour is not a whole food. I want to emphasize what is a whole food, it’s as close to its natural state as possible. That doesn’t mean that cooking meat makes it not a whole food, because we’re processing that, so you can get into all these rabbit holes. But as close to what it came in as possible is the best thing. And really is very personalized, like you said, there truly is a no one size fits all. I’ve seen people be successful on all different types of diets and macronutrient ratios. But I would say in general, because we live in an insulin-resistant society, we have so many people with poor metabolic health and that dysregulated feedback loop for a lot of people lower carbohydrate, higher protein and higher healthy fats is going to be the best option. 

There’s always nuances to that, and there’s always exceptions. But I would say that’s the most successful approach for most people, especially if you’re showing signs of insulin resistance or you’re having really abnormal glucose values. I really like to focus on a nutrient-dense diet and a diet that promotes satiety. Often, that’s really prioritizing protein, fiber, non-starchy vegetables, if tolerated. That’s a whole another bandwagon [crosstalk] we could go on. In general, I want to make sure you’re getting all the nutrients you need. You’re feeling satisfied. You’re not eating around the clock, which I know is something that we definitely agree on. If we’re seeing signs of insulin resistance, we really do you have to cut back on the carbohydrates. 

We all have personalized responses, eating whole food-based carbohydrates, like, how I respond to a sweet potato is not going to be how you respond to a sweet potato. It’s also about finding the– if you do want include carbohydrates in your diet, which you don’t have to, it’s totally fine if you don’t, but if you do, finding which ones work best for your body as well, so let’s try some, see which ones you respond best to uniquely, and then find the right macro combination to eat them in the right portion size, the right meal timing to make those work. Sometimes, just tweaking the total amount a little bit is helpful. But, in general, I would say our modern recommendations for carbohydrates are way, way too high for almost everyone. The standard recommendation is up to 65% of your calories from carbohydrates. I’ve only ever seen that work in a handful of people and they’re all athletes, for sure. It’s not this is the average recommendation for the average person, and it certainly doesn’t work for the average person. So, I would say most people do much better and closer to like 20% to 30% of their calories from carbohydrates, give or take, there’s always the nuances. 

Cynthia Thurlow: Well, I think it’s interesting because I walk a lot of people through intermittent fasting as a strategy. I think one of the things I quoted most recently was that the average American consumes 200 to 300 grams, that’s average, that means you have a lot of people doing way more than those grams of carbs a day. You think about just the beverages, but nothing else, you just track sodas, and fatty coffees or sweetened beverages, people can hit that really easily. If you’re drinking your calories, that’s like one thing that people can omit, like automatically, and just start tracking what they’re consuming, because I think there’s just this disconnect. I say this to my patients in cardiology, I’m like, just because you could eat this way at 18, doesn’t mean that at 50, you can eat like you did at 18 years old, like your body doesn’t need as much calories, you have less lean muscle mass unless you’ve been lifting and being really diligent. So, let’s pivot and talk a little bit about gender differences, because I know that there are definitely differences between men and women. I think it’s important to talk through that so that people can really make educated decisions moving forward. We can’t pretend we’re mini men. I always say this all the time, women are not mini men, and we can’t pretend that we are.

Kara Collier: Exactly, we’re really not. It’s totally different physiological systems. We do have to acknowledge that it may be disappointing to hear, I know, but we all feel a little sad that we can’t eat the same things or do the same things. But again, knowledge is power. If you know this, then you can compensate appropriately. On average, unfortunately, women are definitely less carbohydrate sensitive than men. This is probably for a variety of reasons. And especially, as you age, that sensitivity difference between men and women only gets more pronounced. This is likely due to differences in lean muscle mass. Muscle mass is where we can store glycogen, which is our storage space of glucose. More space means you have more place to dispose that incoming glucose. It’s just this huge sink for glucose, which is why it’s important for everyone to strength train. I’m a huge, huge proponent of that. It’s a wonder for metabolic health, and just moving your body so that you can utilize and stimulate some of that skeletal muscle. On average, especially as we age, men tend to have more muscle mass than women. So, that’s one particular reason. 

The other is, of course, differences in hormones. Testosterone in general improves glucose uptake. There is a well-established correlation between diabetes and low testosterone in men. There’s a strong connection there. In general, some of the hormones that women have more of tend to make it harder to tolerate carbohydrates, hence a whole host of other things that go on there. You can see this, especially in a menstrual cycle. If you’re still menstruating, you’re going to have different glucose values, depending on what time of the month it is. This is something I really had never thought about before I started diving into this and wearing my own CGM. It’s so apparent because any change in hormones, it’s going to affect everything. It’s going to affect your glucose, it’s going to affect your metabolic rate. So, when we have major shifts in hormones each month, it’s going to have an impact.

On average, and again, everyone kind of presents a little differently with this, but most women tend to have higher glucose values during the luteal phase. Weeks three and four between ovulation and menstruation, glucose values, on average are just higher. We tend to put out more glucose, but we’re more insulin insensitive at that time. This is just something for women to know, and if you are going to wear CGM, wearing it for a whole month is really interesting so you can see these differences. For me, this effect is very pronounced, especially that one week beforehand. I tend to be just much more careful about lower carbohydrates, especially towards the second half of the day when we’re all already naturally less insulin sensitive. This is something I can now compensate with. But you don’t know unless someone told you or you have the information from your body. But a lot of women experience this effect, so it’s, it’s very, very common. 

Similarly with menopause. After menopause, you are going to be less insulin sensitive. There’s a sharp decline in estrogen, and that’s an independent risk factor for insulin resistance and carb intolerance. Especially important that our postmenopausal women are really careful about how many carbohydrates they eat, what type of carbohydrates they’re eating, when they’re eating them, and that they know kind of where their thresholds are at, because you’re just in a state where it’s going to be a little bit harder to process that glucose as energy.

Cynthia Thurlow: I think that’s a really important distinction, just to mention that those that are still cycling that there are going to be periods in the month where you’re more or less insulin sensitive. And then for women as they make that transition into menopause, that they have to be more mindful, it’s something that I talk very openly about, and I remind people, and again, I feel like I always get– normally when I’m at speaking events, and I’m standing on a stage, and I’m saying, I’m not really talking about grains and gluten. I’m talking about squash and sweet potato, and root vegetables and low glycemic berries, because we’re such a carbohydrate-focused culture, people feel there’s this lack. If you tell someone not to eat bread, or not to eat cereal or not to eat lots of chips, they take it as a personal affront, and really, it’s designed to say, hey, I want you to pick the most nutrient dense option. Just realize you probably can’t get away with eating a whole sweet potato and maybe that you do half a cup of squash or half a cup of sweet potato because your body is going to have to work that much harder to process that carbohydrate. Whereas you do much better with a higher protein diet, which helps ward off sarcopenia, which is muscle loss with aging that, unfortunately, is a natural function of aging. And if you don’t proactively lift weights, doing weight bearing, exercise, walk, etc., you’re going to be even more risk and the less lean muscle mass you have, the less calories you burn. So, it’s almost a ball rolling downhill that you really have to be much more cognizant. As unsexy as that is to say, as we get older, as women, we just can’t have as many carbs. And it doesn’t mean that you don’t ever enjoy a birthday cake or have a glass of wine but you can’t be doing it every night.

I’m not sure if you see this with your patients. But one of the things I see a lot of women in their 40s, and beyond doing, and especially with COVID, because we have these truly unprecedented times, none of us have lived through a pandemic. There’s just stress and demands on everyone that is unusual for them. You can’t have a couple glasses of wine every night. That is a surefire way to dysregulate your blood sugar to raise cortisol, to dysregulate melatonin. We’re talking about all these different hormones. I’m curious, do you see that as well with your clients and your patients that they start making these associations of like, “Oh, I really can’t do X, Y, or Z anymore?”

Kara Collier: Yeah. That’s where I think a lot of people end up saying, “I came here to try the CGM, to learn about my glucose, or see how things are going.” And they leave as, “It’s more of this was an accountability tool for me.” And this is a behavior change driver. We live in a society, and just as humans, we love immediate gratification, immediate feedback. Our brains are hard wired for that. Unfortunately, a lot of health habits that we want people to be doing and we need for good health don’t involve immediate gratification. If I don’t have that glass of wine tonight, or if I skip that bread tonight, not really going to see the benefit for maybe like 30 years, that’s a big delay. It’s not very motivating, and you’re not sure if you’re doing the right thing. And if you do have the wine, and if you do have the sweets every single night, you’re not really going to see the consequence either. The only thing you’re getting is the immediate reward of it being satisfying. I think the CGM and immediate data just coming right at you can help bridge that time gap so you can see the consequence or the benefit of the decision you made right now rather than 20 years from now. That’s exactly what our brains want to see in order for something to truly be intrinsically motivating.

In order to stick to a lifestyle plan for the rest of forever– we always switch things up, we’re always changing what’s working, but we want to stick to it long term. In order to do that, it has to be intrinsically motivating. I can’t tell you what to do, and suddenly you’re going to be motivated to do that. You have to see it and feel it and believe it, and I think the data is really helpful to do that because you can see, “My glucose was way higher the next day when I had two glasses of wine.” That’s very common, with the effect of alcohol, typically what happens is you see a glucose dip in the moment because your body’s prioritizing metabolizing alcohol, it’s like, “This is my first priority.” So, it’s like, “I’m going to worry about glucose later.” Then the next day, fasting glucose levels are much higher and postprandial, your meal responses, your glucose values are much higher as well, because you’ve just interfered with the liver’s normal flow. You see those effects. 

We have dietitians on staff to help point out those effects, so you can see, like, “Did you make this connection and kind of help put it together so that is intrinsically motivating, and you can stick to something long term?” Because that’s really my goal. You don’t have to wear CGM for the rest of your life. But those insights will hopefully build a motivating plan that you can stick to. The last thing we ever want anyone to do is to have fad on and off, try this thing for three months, stop, and then kind of gain weight, cycle weight, that’s not good long term. That makes it harder to have a lasting successful plan if we’re always switching things. I think it’s very good to try things, but we have to stick with things over the long term in order to see the long-term benefits.

Cynthia Thurlow: Absolutely, I have to totally agree with you. Now, one thing we didn’t touch on is how different types of exercise– This is always a question in my monthly group, we’re all focused on exercise the month of December, how does exercise impact positively or negatively our blood sugar values?

Kara Collier: Yeah. Overall, all exercise is positive. It’s super, super important. You can’t have perfect health without also exercising. But, in the moment, your glucose may spike during exercise, and that could be completely normal. It’s really about how much energy you’re demanding from your exercise. If you’re in a fasted state and you’re doing HIIT training, or you’re doing heavy weightlifting, you’re probably going to see a glucose spike, just because the energy available, circulating is not enough to power that quick, intense workout. Your body will stimulate some glucose for you to use. But it’s different than a food spike, because you’re using it right away, it’s fueling your workout. It’s not just extra energy you put into your body. So, don’t be afraid if you see a glucose spike during an exercise, that’s totally normal. But after exercise, and really sometimes for up to 48 hours, we can see improved insulin sensitivity, especially strength training, but really any type of exercise has shown to be helpful for this. Not just improving insulin sensitivity, which helps require less insulin and to get your glucose down so we’re stimulating less insulin and getting glucose down faster but it also can clear out some of that glycogen in your skeletal muscles and make sure you have more room to put some in if you are eating carbohydrates, and it can increase your mitochondria so it makes it easier to produce energy and process all that glucose coming in. Really, the list could go on and on of the benefits of exercise. 

I’m a proponent of strength training, but I also say do whatever you enjoy doing, because I want you to be doing it regularly. Whatever you can stick to on a regular basis is definitely more beneficial than if you hate strength training, and you’re forcing yourself to do it and you’re not going to stick with it. Any type of exercise helps. Also, making sure you’re not sedentary. We don’t want to work out for one hour of the day and then sit the rest of the day. That’s probably my Achilles heel, because I just work a lot, and so I sit on my computer a lot, so I totally understand how easy it can be to just be sedentary and go to the gym for one hour and think that’s enough. But through the CGM data and through the research, it’s very obvious that you also have to move, and stimulate your muscles throughout the day, that can be a quick 10-minute walk, get up and just– I have a kettlebell by my desk to help remind myself of that. But just making sure you’re moving throughout the day can also really improve glucose values. Especially a quick walk after a meal. If you know your glucose is rising, one of the best ways to help bring it down quickly is just to go on a quick walk. It doesn’t have to be a run. It doesn’t have to be a heavy workout. It can be a 15 minutes’ stroll around the neighborhood, and it makes a very meaningful impact.

Cynthia Thurlow: I was about to say that’s like one of my favorite things to suggest. It doesn’t even matter if it’s 5 minutes, 10 minutes, 15 minutes, 30, take your dogs out, get some connection with nature. I know that you’re in a warmer part of the country. But one of the things that has been beneficial during COVID is, I’ve just been doing more walks with my dogs in my neighborhood and I’ve actually grown to really appreciate it because much like to your point, for those of us that are at home working, you get in this habit of, “Oh, I’ll just get one more thing done,” what really what you need to do is stop, get up, move your body, then come back. And then, I always feel like that makes whatever task I have to get done that much easier.

Now, before we end things today, I want to make sure we touch on two more things. Obviously, intermittent fasting is a strategy that I utilize myself, and ironically enough, I actually had a longer fast than what I normally do earlier this week, in preparation for a colonoscopy. I had to go 40 hours and I was so excited, because I was like, “Okay, this is the first time I’ve done a fast that long in a long time.” But I then had to take medication to prep me for the colonoscopy, which is very sugary, and all I could think of was it’s going to take days for my body to process the amount of glucose I just ingested. In fact, I told my gastroenterologist, they have to come up with better options for people. 

Let’s talk about the impact of fasting and blood sugar for a healthy average person. What are some of the benefits? What are some things that you see? I think there’s always this concern for people. The fear is always, “If I don’t eat, my blood sugar is going to drop,” which I just have to remind them that our body has all sorts of amazing emergency backup systems to ensure with homeostasis, that doesn’t happen. You mentioned glycogen stores and things like that that will help maintain that blood sugar. But let’s talk about the impact of fasting and blood sugar.

Kara Collier: Yeah, and you’re absolutely right. A lot of people are afraid of becoming hypoglycemic if they fast. I’ll tell you that is very, very uncommon, especially in nondiabetics. It’s extremely rare, we have lots of systems in place to make sure that doesn’t happen. If you are wearing a CGM and you’re a little nervous to fast, it’s the greatest time to try it because we know what’s going to happen, and you also have support there through our team. But fasting is one of our core pillars. We talk about how nutrition, fasting, exercise and stress, so I love stress and sleep, and anything that’s a stressor and one category, those are like the four legs of a chair, if we want good metabolic health, we have to do all of those. I’m completely in agreeance with you that fasting is super important. 

As general golden rules for most people, because again, fasting is personalized, just like nutrition, I really like to emphasize at least 14 hours of fasting a day, that’s like a bare minimum for everyone, even my diabetics. They’re 14 hours and really aim for at least 3 hours of fasting before bed. We are universally less insulin sensitive in the evenings than during the daytime. This is everybody. Everyone has this effect. So, earlier dinners align our eating with our circadian rhythm is a good golden rule. Some people, that three hours before bed is enough time. And for others, they really don’t see those overnight glucose values and those morning fasting values come down, unless it’s five or six hours before bed. We might have to move that further up, but three hours minimum.

Then, we just want to avoid grazing. I really want people to be conscious about how much time is between their meals. This is personalized, because everyone’s a little different. But make sure you feel satiated after a meal, so that you can go in between meals without having to snack all day, because if we’re grazing all day, and we’re constantly having snacks between meals, then we’re always stimulating insulin. We don’t want to start that cycle, that feedback loop, where we’re constantly stimulating insulin. Those are my core rules for the general person. From there, we can really take it where we want to take it. There’s the caveat of, people that fasting is not applicable for. I’m sure you’ve talked about this before. Pregnancy, if you’re underweight, but again, that’s not most people.

Then, beyond that, really one thing that I will note, is this was a disconnect from my traditional teaching. When I started to see lots of people’s data, was that if you are insulin resistant, or you are already at the stage of maybe a diabetes diagnosis, fasting is one of the most useful tools we can lean on to get you back down to normal. For an everyday healthy person, general 14 or 16 hours of fasting days is probably just a good healthy practice. But for those insulin-resistant folks, we can decrease their glucose spikes by altering diet, we can lower their glycemic variability by altering diet, but we can never get your average glucose values and your fasting glucose values down to optimal ranges without leaning on fasting heavily because your liver has really dysregulated that ability to maintain good glucose values in a fasted state. So, no matter what we’re doing diet wise, we can’t fix that unless we forced the body to go without food for a little while. We have found kind of longer fast for the insulin resistant people to be just an amazing tool of finally bringing those fasted glucose values down. We first want to address diets and make sure we’ve got the spikes down and that there aren’t any medications where they might be hypoglycemic. But those longer fasts have just been amazing for that category of people. 

Cynthia Thurlow: Well, this has been so, so valuable, I’m so grateful for your time. There is little to no one that I’ve ever had the opportunity of working with who isn’t struggling with some degree of blood sugar variability, or just really not getting their macros tuned in, they’re eating too frequently, their sleep is off, their stress management’s not dialed in. How can people connect with you? I’m sure there are people that are listening that are curious, that may not be diabetic, obviously, I myself am super interested in the preventative aspects of CGM. How can people connect with you and get more information?

Kara Collier: I work at NutriSense. Our website, nutrisense.io is, where you would sign up for a CGM. And every new customer gets a personalized one-on-one dietitian they can also chat with through the app, which I think is really helpful to identify those trouble areas and figure out what exactly is going on. That’s the best place to try it out. We’re also putting out a ton of information about glucose and nutrition and metabolic health on our Instagram @nutrisenseio. And then, me personally most active on Twitter at Kara Collier, but most of my social media goes through the NutriSense account. 

Cynthia Thurlow: Awesome. Well, thank you so much for your time today. I’m so glad we have connected and I know this information will be super valuable for my followers.

Kara Collier: You’re so welcome. Thanks for having me.


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