Episode 341: Special Guest: Kara Collier, CGMs, Glucose Control, Calibration, Placement, Types Of Sensors, Nocturnal Hypoglycemia, Fructosamine, Finding Patterns, And More!

Intermittent Fasting


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Oct 29

Welcome to Episode 341 of The Intermittent Fasting Podcast, hosted by Melanie Avalon, author of What When Wine Diet: Lose Weight And Feel Great With Paleo-Style Meals, Intermittent Fasting, And Wine and Vanessa Spina, author of Keto Essentials: 150 Ketogenic Recipes to Revitalize, Heal, and Shed Weight.

Today's episode of The Intermittent Fasting Podcast is brought to you by:

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LMNT: Grapefruit Salt is here to stay. For A Limited Time Go To drinklmnt.com/ifpodcast To Get A FREE Sample Pack With Any Purchase!

TONE PROTEIN: Get on the exclusive VIP list and receive the launch discount at toneprotein.com!

AVALONX EMF BLOCKING PRODUCTS: Stay Up To Date With All The News On The New EMF Collaboration With R Blank And Get The Launch Specials Exclusively At Melanieavalon.Com/Emfemaillist!

The Melanie Avalon Biohacking Podcast Episode #70 - Kara Collier (Nutrisense)

The Melanie Avalon Biohacking Podcast Episode #130 - Kara Collier

Kara's Personal Story

Listener Q&A: Arietta - My doctor said a CGM would just confuse me. How do I make an appeal to her?

Listener Q&A: Ana - Is a 2 week trial period long enough to get a picture of how your body responds to the foods you eat?

how does a CGM measure interstitial fluid?

Listener Q&A: Jill - Deep dive into the actual accuracy…

Listener Q&A: Nisha - I was so confused by the difference between finger prick blood draw...

Listener Q&A: Linda - My blood testing is always 20 -30 points higher then nutrisense...

Listener Q&A: Debby - When doing whole body cryotherapy is it ok to be wearing a CGM in the chamber?

how often does the device collect data?

Listener Q&A: Alison - Is it possible to wear a CGM on another area of the body?

Listener Q&A: Maureen - it always takes about 1day or 2 to calibrate correctly and during that time I get low level alarms going off...

Listener Q&A: Jill - What is the optimal 24-hr average glucose?

Listener Q&A: Benoit - Assuming I wore one for 3 months, would that mean I can calculate my HbA1C (or get a good correlation)?

the insights tab

Listener Q&A: Nancy - I have a CGM device but I am finding it hard to interpret and make use of my readings.

Listener Q&A: Caroline - Is it more important to track insulin than blood glucose as I’ve heard on some podcasts?

Listener Q&A: MaryJane - In your opinion, what’s the greatest benefit to using a CGM? Besides big spikes or big drops in blood sugar what are other patterns of concern to look out for? 

Listener Q&A: Margaret - If blood glucose is shown to be relatively stable (no major spikes) with a CGM what is the next step to assess if weight loss is the goal?

Listener Q&A: Jill - I recently heard some discussion of the dawn phenomenon….

Listener Q&A: Xenia - What to do with the information?

Listener Q&A: Jackie - What is the initial cost of the CGM and continuing cost for supplies and monthly membership? 

NUTRISENSE: Visit nutrisense.com/ifpodcast And Use Code IFPODCAST To Save $30 And Get 1 Month Of Free Nutritionist Support.

Our content does not constitute an attempt to practice medicine and does not establish a doctor-patient relationship. Please consult a qualified healthcare provider for medical advice and answers to personal health questions.


Melanie Avalon: Welcome to Episode 341 of The Intermittent Fasting Podcast. If you want to burn fat, gain energy, and enhance your health by changing when you eat not what you eat, with no calorie counting, then this show is for you. I'm Melanie Avalon, biohacker, author of What When Wine, and creator of the supplement line AvalonX. And I'm here with my cohost, Vanessa Spina, sports nutrition specialist, author of Keto Essentials, and creator of the Tone breath ketone analyzer and Tone Lux red light therapy panels. For more on us, check out ifpodcast.com, melanieavalon.com, and ketogenicgirl.com. Please remember, the thoughts and opinions on this show do not constitute medical advice or treatment. To be featured on the show, email us your questions to questions@ifpodcast.com. We would love to hear from you. So, pour yourself a mug of black coffee, a cup of tea, or even a glass of wine if it's that time and get ready for The Intermittent Fasting Podcast. 

Hi, friends. Welcome back to The Intermittent Fasting Podcast. This is Episode 341 and I'm Melanie Avalon. I am here today with a very special guest. I have been looking forward to this, friends, for so long. So something that we talk about all the time on this show, like, all the time, is CGMs also known as-- well, continuous glucose monitors, also known as CGMs, which are devices that you put on your body, and they give you a picture of your blood sugar levels measured through interstitial fluid, which I'm sure we'll talk about, essentially 24/7 for a two-week period when you're doing a program. And me and honestly all of the cohosts that we've had on this show, Gin, Cynthia, and now Vanessa, we are all huge fans of CGMs. We've worn them multiple times. And that's just because it's really one of the only ways to get an actual picture of how your food is literally affecting you in that moment, how your fasting is affecting you, your exercise. It's just so incredibly eye opening. 

And so we've partnered for quite a while now. My favorite brand in the continuous glucose monitor space to make them accessible to people like us, because historically, you needed to be diabetic and have a prescription from your doctor is a company called NutriSense. We love NutriSense. So they provide access to CGMs. You get the CGM, you get the CGM app, the NutriSense app. It helps you interpret your data, and it's just really an easy process, an eye-opening process. I am obsessed with it. So I knew we had to have the co-founder on this show. I've had her on the Melanie Avalon Biohacking Podcast twice, actually. So I will put links to that in the show notes. But I have here now with me. And I also gathered a cacophony of listener questions from you guys. You had so many questions, so we're going to go through those. But I am here with Kara Collier. Again, like I said, the co-founder of NutriSense, and she is now the VP of Health at the company, and she is awesome. So, Kara, thank you so much for being here. 

Kara Collier: Yeah, absolutely. I'm so excited to chat.

Melanie Avalon: I am too. I've been looking forward to this for so long, especially because, like I said, we haven't had a full discussion about CGMs on this show. When I asked for questions, I got really excited because I got so many. A few of them had never occurred to me, which was I'm really excited to ask those. So to start things off, your personal story, what led you to co-founding NutriSense? 

Kara Collier: Yeah. So I first tried a CGM probably about three years before founding NutriSense. So at this point, probably eight years ago kind of where I started, I'm a dietitian by trade and I started in a traditional clinical nutrition world. So I was working in hospitals with pretty sick patients, mostly ICUs. So I was seeing a lot of people come in with complications of diabetes, complications of uncontrolled heart disease, complications of uncontrolled kidney disease. What you see in the ICU is a lot of suffering, pain, time spent, expenses, all of this happening that you realize really didn't ever need to happen in the first place. So I was trying to make a difference in people's lives. I was trying to help them with lifestyle changes, with nutrition, with counseling and it was the wrong time and place to be really intervening in the way that I wanted to. 

So eventually I went to a different startup, but was really mulling on this problem that I felt like I was seeing in the clinical world. And at that point, I had worked with patients who wore CGMs, primarily type 1 diabetics and occasionally a type 2 diabetic. And I realized how powerful they were for that audience. But I started to get really curious about trying them, both on myself and others. So I got a hand on a couple, which, as you mentioned, was very hard to do at the time. It took me convincing some of my physician friends to get them. I realized even being really nerdy in the metabolic health and nutrition world and having learned a lot about the topic. When I wore one, I learned so much about myself that you just can't know without the data. That was my first moment where I was like, “Oh, wow, these are powerful tools and not just for managing your diabetes.” 

So then I started putting them on my friends, my family to see what their experiences were like, and I found it was powerful for almost any type of situation that person was in. And that's when I got really excited about the technology and I realized how difficult it was to get them. And then also the app that comes with the device normally is pretty useless. It basically just tells you your glucose value and it's meant for your physician to look at it and dose your insulin accordingly. So I realized for this to be useful for consumers, you needed a completely different app experience. So from there, I actually just stumbled upon through friends of friends, my two other co-founders, both of which come from a technical background and a finance background, and they were looking for somebody who had the nutrition subject matter expertise, and they had a very similar thesis for the business. We just totally meshed and got along really well. We had the same values for how we wanted to create a business, and we just started doing it and going for it, and then suddenly, we had customers and suddenly we had more customers and then we’re like, “Should we quit our day job?” So it really just took off. And that was a little over, that was about four and a half years ago now.

Melanie Avalon: I'm having to stop myself because I would love to have just a two-hour conversation about the entrepreneurial aspect of this, and product development, and creating the app, but I will not go down that route. Wow. So incredible. I'm just curious. The first time you got it from your doctor, we actually had a question talking with doctors about CGMs. So I'll just make a really quick two-part question. Arietta asked, she said, “My doctor said a CGM would just confuse me. How do I make an appeal to her?” My little random question is, when you did first get your CGM, did you have a practitioner that listened to you and was open to prescribing it, or how did you do that? And then what would you say to Arietta’s question about doctors just being a little bit skeptical about CGMs? 

Kara Collier: So for me, my situation was probably a little unusual and it might not be as helpful for everyone else. Since I worked in the healthcare setting, I had friends in the hospital system. So they weren't my doctor specifically, but they were willing to just give it to me as colleagues essentially. So if you have an in in the healthcare world, that's one route. But if you're trying to convince your doctor-- I get this question a lot and it's very difficult. This is part of the reason we created the company. So obviously, a small plug for NutriSense will take care of this problem for you, but if you really want to go through your doctor because you might be able to get a cheaper sensor that way, which I totally understand, I'd rather have everybody wearing it in some way than using NutriSense necessarily. One point to explain is that there's a lot of research and information out there now. So you can even use the blogs and the content on NutriSense's website, other websites, these podcasts to try to make sense of the data. That's part of what we try to do in our app for you. But if you aren't using our app, you will have to do a little bit of learning on your own. But many people are completely capable of doing that. 

But the other thing to help educate your physician is that awareness is really the first step to health. We don't know what we don't know and we need the right tools and information in order to understand if we're where we think we are. We can dig into the traditional glucose metrics, if you'd like, but they only tell us a little bit. So there's a lot of research out there showing how the first signs of glucose dysregulation or deviation typically happens in that post-meal period, so that postprandial glucose response. So our glucose spikes, how we respond to meals, the fluctuations throughout the day, what's called glycemic variability, which is those swings in our glucose. There's a lot of research to indicate that those two things which you can only understand if you're measuring it 24/7 through a CGM are much earlier warning signs of insulin resistance, metabolic dysfunction. And so if you can understand what's happening with those data points, you can make sure you're in really good metabolic health before you ever even get to deviations in the more traditional metrics. 

So from a preventative lens, it's really the route to go. It also really helps drive behavior change, which we can dig a lot more into. But data is powerful, especially real time data. So even just the benefit of something like a Step Tracker like we have our Apple Watch or our Garmins or our Oura Rings, these really help us stay accountable to the things that we might know already, which is maybe I should walk more or I should do some mindfulness practice. But having that data that comes back at you in real time helps you stay accountable. That's another powerful reason for the CGM alone is to really help you be able to make the behavior changes that you know you might need to do that you might struggle doing. 

Melanie Avalon: I love that so much. It's something that's so hard to communicate until you experience it. But the level of accountability that I think it can bring to people because once you finally see it in real life, see this graph of what you're doing and how it's affecting you, it makes it real to you. I think it makes your food choices and your lifestyle choices, real. [giggles] You understand what's happening.

Kara Collier: Exactly. It's so different when you have the data. Even then, when you aren't wearing a CGM anymore and you don't have the data in front of you, having seen it at some point in time really does still drive behavior change in the future. So you don't necessarily have to wear it forever to have that really powerful behavior change impact. So it's pretty incredible. And then of course, there's the aspect that we're all different. We have different unique responses to food, to activities, and we're not all the same exact person. And so there are some things that are just unique to me that nobody else is going to respond in that way. I don't know that information unless I see the data and I test it out. And so learning those type of just bio-individuality really helps you to be empowered to make decisions that are right for you specifically.

Melanie Avalon: Speaking to I love what you just said about how having seen how you react to things, you remember that in the future even when you're not wearing a CGM. So what I often say is I really wish that everybody in the world could wear CGM, at least just once because like I said, it lasts two weeks. But then beyond that, I know with NutriSense, you guys have a really great subscription program, so people can do it longer. Anna or Anna, probably Anna, she wanted to know, “Is a two-week trial period long enough to get a picture of how your body responds to the foods you eat?” So that two weeks, what can people realistically get value wise from that? 

Kara Collier: Yeah. We recently changed our lowest option from that two-week to the one month, so you get two sensors. If you're a previous customer and you've had the two-week trial from us in the past and you just want one more sensor, we will do that happily. But if you're a brand-new customer and you've never been with us before, our lowest tier now is one month, so two sensors again. We primarily did that because we really feel like a month is the minimum amount of time to be really helpful. There are exceptions to this for the person who's really knowledgeable. So somebody who maybe lives and breathes these topics as their primary day job, you might be able to have two weeks and you get away with it and you learn most of what you need to learn. But for a lot of people a month is really helpful. You might not even wear them back to back. You might do the one month and have the two sensors and wear one and then wait a couple of weeks and then wear the other one. 

But we think having closer to that 30 days of data is that sweet spot for the minimum amount of information, because ideally what you want to do is at least, first, test your baseline information. So what are your normal day to day habits doing to your data? Because we want to know-- It's really interesting when people are like, “Oh, I want to try my favorite treat that I only have once a month.” That's fun. But what we really want to know is how is your daily routine affecting you? Because that's what's most impactful on your overall health. So we want people to not change anything. Then based on what you're learning, maybe you're seeing that there's one meal in particular in your regular routine that really is resulting in a high glucose spike. So then you might want to experiment with a couple of different variations of that meal until you land on something that's working really well for you, and then maybe trying some of the more fun things that you don't do necessarily every day. To really get that information and takeaway, I think two sensors is a sweet spot.

Melanie Avalon: Because there's a lot more questions, but could you briefly explain, because I mentioned this in the intro, so it's not actually measuring your blood. How is it working with measuring the interstitial fluid? 

Kara Collier: Yeah, good question. So the CGM is actually measuring, like you mentioned, what is called your interstitial fluid. This is part of the reason that the sensors are so painless and you really don't notice them. So to answer the question that I know will come to is, does it hurt? It really doesn't. You put the device on at home, so it's not something that you need to get inserted. It has a small needle for insertion. But what that needle is placing is a little tiny microfilament, that's flexible, no needle that stays just below the surface of the skin. And what that microfilament is then picking up on is that the glucose in your interstitial fluid. What that is is essentially the fluid in between your cells. So you're not even going to the depth of your blood vessels, which is why it's really shallow, really painless. And how the interstitial fluid works essentially is just like normal diffusion. So let's say you eat a gummy bear, and that gummy bear gets immediately digested into glucose because it's basically pure sugar. And then it's going to go into your blood glucose first, and then it's going to diffuse into that interstitial fluid. 

So if we're not eating anything, if our glucose levels are relatively slowly shifting, then blood glucose and interstitial values pretty much match exactly. But if you ate something, let's say you ate 50 gummy bears, and your glucose spiked really high really quickly, you will see that reflected in your interstitial fluid usually like 15 minutes to 30 minutes later. So there's that slight delay with these sharp changes in your glucose, but it is reflected in the same way. It just needs to be diffused into that space. 

Melanie Avalon: So actually, speaking to that, we had quite a few questions about comparing it to blood glucose and the accuracy. This was a really interesting question. So from Jill, she wanted to know about the accuracy, and she said, “She was shocked when she researched the allowable variance from a blood draw or a finger prick.” And then she said, “Do factors like inflammation significantly affect accuracy? Since interstitial fluid may be higher in someone with higher inflammation, I believe this is the reason they have not been studied in pregnancy.” Do you have thoughts on that? 

Kara Collier: Yeah, that's a great question. So just to address accuracy broadly, like she's mentioned, so these are FDA-approved medical devices. So there are two main manufacturers who create the CGMs, Dexcom and Libre, and both are FDA approved. But what the FDA does allow is essentially a 15% variation from what you might get at a lab draw 95% of the time is what FDA deems to be acceptable accuracy. But how this works, typically, is there's a difference between the precision and then the absolute value. So usually, if it is off within that 15%, let's say, it's at that high end of what's acceptable. So let's say your CGM readings are reading 15% higher than if you had the equivalent glucose value drawn from a blood value and that's different than a finger prick. I'm talking like a lab draw. 

Then what happens is it stays pretty consistently 15% higher though. So it's not going to be shifting constantly on the CGM readings. It's the absolute value might be off. So one thing that we do allow in our app is the ability to calibrate each sensor to get it closer to that true absolute value. But the thing that is nice, if you don't have a recent lab value to calibrate with is that those changes in glucose are very precise. And so it's still very useful to understand that my fasting glucose is resting 10 points higher than it was yesterday, what did I do differently? Or, my glucose shot up 80 points with that meal, what was in that meal that I need to change potentially? 

Then the source of the inaccuracy, that's an interesting question with pregnancy. The reason from my understanding from the manufacturers that it hasn't been necessarily approved with pregnancy is because there's such large fluid shifts that happen during pregnancy. So it's kind of a fluid balance thing rather than an inflammation thing. I haven't heard that or read that anywhere with the inflammation aspect. Most likely you're going to be having a similar level of inflammation throughout the body that's impacting both levels. But the accuracy issue is more related to like I guess, the enzymatic reaction that happens within the sensor itself. Sometimes it can be a little off, but again, it's that change in glucose and that precision that is really useful and stable. 

Melanie Avalon: You just said like, if an enzymatic reaction, why would it be so stable but off? 

Kara Collier: Yeah. It's very hard to find the answer to this. So I will say it is hard to find the answer. We've spoken with the manufacturers who make the devices. We have read all of their studies. What they have done though is they've done clinical tests that you need all of this data to get FDA approval. That's where we know that the precision is very good because what they do is they have people wear it and they do these blood draws over and over throughout the 14 days to make sure that it is more of the absolute value that is off rather than the variation between the values. So we do know that from the studies that have been done. But the reason why is hard to get a firm, clear answer. 

What they typically say is that it has to do with placement. What we have found anecdotally is that people who are really, really lean and have less body fat tend to have more variation from that baseline. And so it might just have to do with the placement and where that microfilament ends up sitting is my theory. That's what I meant about the enzymatic reaction that's happening on that little microfilament. If it happens to be placed a little strangely, it might be slightly more off than others. What is interesting for me is I have only had maybe one sensor out of 100 that I've ever needed to calibrate. So for some people, it seems to just always be spot on every single time. Whereas for some people it seems like it's like, “Oh, every time I need to adjust it by 10.” So it seems to almost be relatively consistent with people, which is another just purely anecdotal observation we've had. 

Melanie Avalon: I can share my experience because I don't know, I was just thinking how many I've done. I've probably done maybe like 15 or so rounds. I think I've had to calibrate probably three times or four times. Actually, the last time I did it, that was the only time where-- Because I did have the exact experience that you're saying right now, which is once you calibrate it-- Basically what I do is I get the CGM and then you wait-- It's 72 hours that you're supposed to wait for the calibration period. 

Kara Collier: Just that first 24 hours. 

Melanie Avalon: Oh, just 24 hours. Okay. I thought it was longer. So 24 hours in the beginning where it might be off, which by the way, do you know why that is? 

Kara Collier: What is explained again from the manufacturers is it's self-calibrating during that time. I think a lot of it has to do with just potential damage that has been done with that puncturing. Like, some of that minor inflammation that happens with that needle during insertion and maybe even a little bit of bruising or a little bit of bleeding interferes with that at first until it clears out. 

Melanie Avalon: That was Peter Attia’s theory. I heard him saying that on a show and I was like, “I wonder if that’s--" Okay. That's exciting to hear that. Yeah, so basically what I do is I have that 24 hours where I'm not judging. I have, at home, a finger prick and a glucometer and I will check it against that. With the recommendations and maybe you can elaborate on this, but when you're checking it, you want to make sure that you're still and not eating and not moving around a lot. Basically, being in that state, like, Kara was saying earlier in the show, where the blood should mostly be matching the interstitial fluid anyways because there's not that time delay. 

Kara Collier: Right. You want to be stable.

Melanie Avalon: Yeah. So I make sure I'm in that state and I check it. I'll see if it's off, and then I'll do that a few times, typically, that next day and maybe even the next day if I'm a little bit suspicious. Because actually, before I continue on that train with the glucometers, because that's what I wonder, I'm like, “Well, how do I even know my glucometer is accurate?” And then Nisha, she said, “She was confused about the difference between her finger prick and her CGM.” She said, “Sometimes there is a 30-point difference within three minutes when I took 10 blood pricks as an experiment. I also read that the finger prick blood draw sugar can vary depending on the finger and the amount of blood, but I'm not certain.” So question there, if we are even comparing it to our glucometer at home, how do we know if our glucometer is accurate, and does the finger matter, and how do we figure that out? 

Kara Collier: Yeah. That's the biggest challenge with this is that the glucometers that you can buy over the counter, you can get online. They also have their own accuracy issues. So they are susceptible to the same accuracy guidelines. As she said, you could do an experiment where you can probably prick each of your fingers or same finger multiple times, and you're not going to get the same exact number every time. What I recommend is that people use their latest fasting blood glucose value that they got from a lab draw if it is recent. So again, if it's not recent and you do have a glucometer, you can use that as a general gauge, especially if you think it might be really off and adjust that, but just know that it's not a perfect measure either. 

So what we don't want people getting too obsessed with is pricking their finger 10 times every day for the whole 14 days and constantly readjusting it because that's just going to drive your stress levels up. And so getting it, adjusting it a little if you think it needs to be, and then really paying attention to those trends. And then I recommended-- a very, very minimum, people get labs every year as well. So at least at that annual basis, double checking what your most recent fasting glucose level was as a baseline for that information. 

Melanie Avalon: Okay. So to clarify about that, you're saying, if somebody has a CGM and they're not pricking their finger, they can look at the fasting levels from the CGM compared to a blood test they had a while ago for their fasting blood sugar levels? 

Kara Collier: Yeah. We recommend, assuming that what we'll ask our customers when we're talking them through this is, if they've had a fasting glucose level from a lab draw that's in the last six months, if they haven't had major lifestyle changes since, we'll just use that as a general baseline. If it's older than that or if in that six months you've made major lifestyle changes, you've lost a lot of weight, you've changed your dietary habits, then it's probably not that useful as a baseline. But for example, I just put a sensor on yesterday, and I got a lab draw done three weeks ago. So I'm just using that fasted glucose value from that lab draw is my source of truth to adjust if I need to adjust my CGM. But if you don't have that, you can do the finger prick, and just keeping in mind that we're using that as a general proxy and not as a gold standard. 

Melanie Avalon: Okay. Would people if they're doing that, would they probably--? Especially because a lot of our listeners are intermittent fasters, so they might have various eating and fasting windows. I'm assuming if they go that route, they would want to look-- Yeah, it should be on there. They would want to look at the time of the blood draw and probably compare it similarly to the fasted time on the CGM?

Kara Collier: Yeah. Just making sure, you should be fasted going into the lab draws, so making sure both times you're in a fasted state that it's a general same time of day. So typically, they'll want to do labs more towards the first half of the day because it's required to be fasting. So matching that is a good best practice. 

Melanie Avalon: It's so funny. This is just random. I tend to go into labs. I'm always like the last appointment of the day, and I always get the same question. I can't tell you how many times. They'll be like, “Oh, we actually can't draw this lab because we have to be fasted.” I'm like, “I am fasted.” [laughs] 

Kara Collier: Yeah, that's happened to me too. Yeah. [laughs] They can't fathom it. 

Melanie Avalon: No, they'll just assume that I ate. I'm like, “No, it's fine. You can do it.” [giggles] So I'm curious. In your experience, because you said you've done it 100 times or so, the last time I did one-- I don't want to scare people away from them because, like I said, the majority of the time, they haven't needed any calibration, and when they did, it was off by 10 or maybe 20, and then it was fine. The last time I had one, I think are there some that are lemons? Basically, I adjusted it and it needed to be calibrated, for sure. So I calibrated it. Then I think it went back to being accurate without calibration. So then it was like way off. I gave up on it two thirds of the way through. I was like-- [giggles] So does that happen with people ever? 

Kara Collier: Yeah. What we see typically, and this is similar from what the manufacturer's data is as well is about 2% of sensors are just like lemons, like you said. And in those instance, if you reach out to us, we'll replace them for free, because we do know just like every once in a while, for whatever reason, bad sensor. Sometimes it'll just not read at all or sometimes it looks really wacky. Again, it tends to be about 2% of the sensors and we'll replace them happily. 

Melanie Avalon: Okay. Awesome. Yeah. I think for mine, in the beginning it was way high, so I had to really adjust it lower, but then I think it got back to normal. So then it said I was basically dying from hypoglycemia. So I was like, “I don't know what to do with this.” 

Kara Collier: Yeah. In those instances, we would replace that sensor for sure. 

Melanie Avalon: Awesome. Okay, that's great to know. Linda wants to know, she says, “I have another two weeks with a second CGM waiting because I have a salt water pool and it says you can't go in salt. So I couldn't swim for two weeks, plus I'm going to the ocean. So now I will probably purchase in the fall or winter, not the summer.” So is that a concern, the salt water? 

Kara Collier: Typically, we recommend not being immersed in it for more than 30 minutes at a time as just a best practice. But what we have found is there's always people who are like, “No, I'm not going to follow that rule.” [giggles] When they cover it with the bandage that comes with it, most people are okay because we do have people who do like the open ocean swimming, open water swimming in some of the saltwater, and they'll do it for longer than 30 minutes. Nine times out of 10, the sensor is fine, but you are putting at a slightly higher risk of just getting water logged and malfunctioning. So the official recommendation is to not be submerged for more than 30 minutes at a time. 

Melanie Avalon: Okay. Awesome. And then this is one I think I asked you about before. I am still perplexed by this because it seems that-- Oh, although I had a theory about it, which I will ask you, but whole-body cryotherapy. Debbie wants to know, “When doing whole body cryotherapy, is it okay to be wearing a CGM in the chamber?” I know what I see when I wear it is that it spikes way high when I'm in the chamber, like way high. Then I get out, and then it progressively goes lower throughout the day. I was always wondering if it was just the cold freaking it out or if it was a massive dump of liver glycogen. But I'm guessing it's just the cold. What are your thoughts on that? 

Kara Collier: Yeah. Most likely it's just the cold. And so you can wear it in both-- any type of cold therapy, but also any type of heat therapy. So sauna, you can wear the sensors. It's not going to break it, but you might get that extreme response in the moment because there is just like a normal operating temperature for the sensors that probably when the manufacturers made this, they weren't expecting people to be in extreme temperatures. So in those instance, it might just have that higher response. What we know from research in cold therapy is that, usually, you're not having that huge glucose response in reality. Typically, actually, cold exposure will drop your glucose levels, which is usually what people see once they get out of the actual temperature exposure, and the sensor is back in normal temperatures, you'll start to see that glucose drop like you said you saw. 

But with sauna, actually, we do know that individuals have a higher glucose response in reality during the actual sauna exposure. So it's not just that the sensor is reacting to those high temperatures, but it's also that glucose tends to rise in that moment. But again, that's not necessarily a bad thing. This usually has to do with the fact that it's like exercise. So your body is working harder, especially in a sauna, and that's causing the glucose to go up a little bit, and it's also a lot of to do with that fluid distribution. So part of it can be a little bit of acute dehydration that's happening. But just like exercise, when we see glucose rise during exercise, we see glucose values lower overall after the sauna and that long-term benefit of sauna use is lower glucose values overall. 

Melanie Avalon: Awesome. Okay. Yeah, the realization I had related to it, so the device itself, is it gathering information every five minutes that it's actually taking a reading? 

Kara Collier: Yes, every five minutes. Correct. Yeah. 

Melanie Avalon: Okay. The moment I had where I was like, “Oh, this is definitely the cold, not a moment is,” it would only happen because the session is three minutes. So sometimes the session-- that reading check would not happen during the cryotherapy. And in that case, I didn't see any spike on my readings. So that's when I was like, “Okay, so it definitely has to be definitely the cold since there's like no residual stuff going on there.” Just a comment before I forget on, whether or not it's painful. It's funny. So I have a lot of videos. People can check out my Instagram, a lot of videos of putting on CGMs and how to put them on. I think it's one of the things that is the biggest difference between how it looks like it's going to feel versus how it feels, like it looks very scary. 

Kara Collier: It's a little intimidating. Yeah, your first time you do it's a little intimidating. 

Melanie Avalon: Like, the needle looks really scary, but it's just so funny. I think it's funny because I have a video with my friend and I putting them on, and her reaction because you literally don't even feel it. So it's funny to see people's reactions about, because they're anticipating it being painful, but it's really not. 

Kara Collier: Yeah, they're wincing, and then it happens, and then they're like, “Oh.” Yeah, the reactions are great. 

Melanie Avalon: Also, speaking of the placement, so can you explain exactly where to put it? We got a lot of questions about that. So, Jill wanted to know, “Where to put it on her body?” Allison wanted to know, “Is it possible to wear a CGM on another area of the body?” She says she has lymphedema in both arms, and she wants to avoid potentially introducing an infection. And then Nancy said that she wears hers on her abdomen, so placement. 

Kara Collier: Yeah. Again, there's the two manufacturers. We are starting to integrate with both, but we primarily use Abbott Libre. And with the Libre, they have only clinically tested and approved for it to be on the back of the arm, so either arm. And that's just the placement that they have done all of their clinical studies on, all of their accuracy data is with that placement. So that is the only recommendation for the Libre, where the Dexcom has been clinically tested on both the back of the arm and the abdomen. So those are approved for both of those use cases. But again, not everybody listens to the official rules, and we have seen people put it all over. So we've seen people put on their abdomen, their thighs, their butts, they put it in different places, and it typically, 99% of the time works okay, but it is not an official recommendation on our end. So if the sensor malfunctions and it's in a weird spot, that's a risk you take. But the official recommendation for the standard sensor we use the Libre is the back of the arm. 

Melanie Avalon: Is it the fattiest part of the back of your arm? 

Kara Collier: Yeah, that's what we recommend. Mm-hmm.

Melanie Avalon: I would be interested putting it on-- If you're putting on a much more fattier area, I just find it interesting that do people see a bigger lag time? 

Kara Collier: Typically, people see that it looks about the same. Our sample size of people putting it in strange places is much smaller than but with the arms, so it's a little bit hard to tell. But we haven't seen anything that's been a noticeable difference for those who are deviating there. 

Melanie Avalon: So right now, are you using both versions or just the FreeStyle? 

Kara Collier: Not yet, but we are currently working on the integration to be able to offer both Dexcom and Libre. And then one thing that will be coming soon is that we'll be having a membership plan. So if you have your own sensors, you can just have a onetime annual fee to use our app, and access to our dietitians, and bring your own sensor. And so that is part of the reason we want to be integrated with all the different sensors out there is to give people that flexibility. In case maybe you did get the sensors yourself, but you want the better app experience and what comes with the sensor. We're working towards providing those various flexible options for people to use it.

Melanie Avalon: My hesitancy with the non-FreeStyle Libre options, I don't know when they introduced this, but I'm concerned about EMF exposure. And so the Bluetooth aspect, when was that a nonnegotiable with a Dexcom? Which version do you know? 

Kara Collier: I can't remember when they switched, but it's been a while. It's been at least two generations of Dexcom sensors are Bluetooth. 

Melanie Avalon: Yeah. So I wish they would have an airplane mode. I'm just like putting it out there. I'm just putting it out there. Yeah, that's why I've been definitely preferentially at present choosing the FreeStyle Libre. I'm waiting with bated breath. I'm like, “Don't switch to Bluetooth with mandatory only Bluetooth.”

Kara Collier: Yeah. I will say that the version of Libre that has been released in Europe but not the US is a Bluetooth version. Yeah, it seems to be the trend, but we'll see what happens in the US. It's much different ground-- playing field here. 

Melanie Avalon: So this will speak to how much I believe in CGMs. All of that said, because listeners know how intense I am about EMFs. I'm actually launching an EMF blocking product line. It's so important to me. That said, if the only option was Bluetooth only, I still think everybody should do at least one round of it. So friends, that is how important. That is how amazing and life changing I think CGMs are. So one other question about numbers that might be a little bit off when you're sleeping. I know people sometimes experience issues. So Maureen said that, “She gets low level alarms going off in the middle of the night when she knows her glucose is not dangerously low.” Is there anything she can do about that is? 

Kara Collier: Yes. Well, first, I will say the alarms are, what I would consider a very annoying feature associated only with Bluetooth and Dexcom. So there will be no annoying alarms with the Libre's and the NutriSense experience. But what does happen sometimes is that if people are putting a lot of pressure while they're sleeping on the sensor, it can cause your glucose levels from the CGM readings to artificially dip really low. And the reason you'll know if this is real or not is if it's a really sharp dip, let's say your glucose levels were floating pretty stably at 70 and then you see this sharp dip for just like one reading or two readings to 30 and then back up to 70, it was probably you just laying on it funky. 

Where some people really, truly do have nocturnal hypoglycemia, but the pattern looks a lot different. You'll see a more smooth dip that stays a little longer and almost always, 9 times out of 10, if somebody's having nocturnal hypoglycemia, it's associated with symptoms. So during that hypoglycemic moment, they are sweating, they're waking up, they're having that hypoglycemic symptom. Sometimes people will have nightmares, typically. If it's that just like sharp, really quick dip and you didn't wake up at all, you slept like a baby, it's probably just sensor pressure that's causing that dip. 

Melanie Avalon: Okay. Awesome. I definitely experience the pressure experience with mine.

Kara Collier: We tend to see that, really lean people see that more. So that makes sense. 

Melanie Avalon: Okay, got you. Side sleeper here. I'm actually doing an episode in the next few months with a guest who hopefully will convince me to start sleeping on my back. 

Kara Collier: It's so hard though. [laughs] 

Melanie Avalon: No, I still have his Neck-- I think it's called like the Neck Nest or something. It's a pillow to make you sleep straight. I haven't even started doing it yet, but we'll see. Okay. So as far as actually interpreting the data, we got a lot of really, really great questions about this. Where to start? So just a really simple question. Jill wants to know, “What is the optimal 24-hour average glucose?” 

Kara Collier: Great question. So with average glucose, we recommend as an optimal to be at least at a minimum, below 105 mg/dL. So that's really that upper threshold. We really want people to below it, which equates, if you're thinking about things in terms of a hemoglobin A1c which is that blood metric that captures your average glucose over the last three months, that is a 5.3%. Whereas normal for A1c levels for the official recommendations out there in the medical world are anything under 5.7, which would equal to 117 average glucose, which we believe is too high. So really keeping it below 105. 

Melanie Avalon: Okay. Awesome. I said earlier, there are some questions that never occurred to me. I love this question. This has never occurred to me to ask. So this is from Benoit or Benoit. Hope I'm saying that correctly. He says, “Assuming I wore one for three months, would that mean I can calculate my HbA1c or get a good correlation?” 

Kara Collier: It does. Yes. That's a great question. We do encourage people to do that because A1c isn't actually that perfect all the time. I don't know how much you've discussed this before, but there are a lot of potential errors with the A1c values. I think the latest statistic was that it's about a 40% to 60% sensitivity and 80% specificity with the A1c, which means, it misses a lot of positives that you might identify in like an oral glucose tolerance test or the CGM, and it misses some false negatives too. So, long story short, to say that the A1c typically has flaws because it is based on the assumption that your red blood cells live for 90 days, because it is making the calculation based off of how much glucose is stuck to that hemoglobin molecule for the past 90 days. 

But a lot of people have different red blood cell turnover rates. So sometimes they live longer and sometimes they live shorter. And that might skew that A1c percentage either a little high or a little low. If your A1c is 10%, your glucose is high, hard stop. But if your A1c is 5.5% and you calculated it with the CGM as more closer to 5.4%, that deviation could actually be meaningful to you and probably closer to accurate on the CGM assuming that you are checking in on the calibration there. 

Melanie Avalon: That's awesome. So basically, especially, if you've had historically, a lot of HbA1c tests, this would be a great way to know if-- Again, I understand that factors possibly could change, but it could be a good way to know when you get your future HbA1c data if it tends to skew one way or the other. 

Kara Collier: Yeah, absolutely. 

Melanie Avalon: How do you feel about fructosamine? 

Kara Collier: Fructosamine is interesting. So it doesn't have as many flaws as the A1c. Essentially, it's capturing your glucose over the last two weeks as opposed to the three months. It's more reliable if your red blood cell turnover is abnormal outside of that 90 days. So in situations like pregnancy, if we're concerned about glucose levels, they'll more likely to use fructosamine rather than A1c, because red blood cell turnover is all kinds of crazy when you're pregnant. So it's more reliable in that sense. So if you have something like a known issue with your red blood cells, like, there are some genetic conditions where your turnover rate is different, then fructosamine is going to be a much more useful metric for you. 

Melanie Avalon: Okay. Awesome. Maybe now I'll share my HbA1c CGM story. I've shared it quite a few times on this show. It's just so shocking to me, this experience I had, and it further drove home my obsession with CGMs. So historically, I've worn a CGM a lot. The diet I've been following for quite a while now is intermittent fasting. I do one meal a day. And at night, I eat huge amounts of lean protein, lots of fruit, cucumbers. So it's high protein, it's low fat, and that I don't add any fat. It's just lean protein and then tons of fruit. So a pretty big carb load. And so whenever I've worn CGMs in the past, I am always really curious to monitor that spike from that massive fruit intake. I'm usually always good. It doesn't normally go above-- Well, it depends. In the past, it would go up to like 130-ish a little or higher, sometimes even 140. But then with some lifestyle changes, like taking my berberine supplement that I make, it actually was going-- it wouldn't really go above 120. 

Point being also historically, my HbA1c has been usually around 5. Yeah, usually around 5. So I made one change to my eating pattern. I made that change for about a month and I intuitively felt like it was probably a problem. But I wasn't wearing a CGM and I was like, “It's fine. It's all good.” And then I went and got my blood tests and my HbA1c had gone up to 5.8 in a month. I freaked out. I was like, [giggles] “What is happening?”

Kara Collier: It's a big jump. Yeah.

Melanie Avalon: I know. So I immediately stopped what I was doing, which what I had been doing, and I find this so interesting. I had not changed the amount of food I'd eaten. I was eating the same foods, but I had started heating my fruit because normally I eat the fruit frozen and I realized that when you heat it, it made it taste like dessert, like, pie. So I was just heating the fruit. That's the only change. Same amount of fruit. And so I stopped doing that completely, went cold turkey, went back-- no pun intended, because I literally started eating it frozen again and started wearing a CGM. A month later, it was down to 4.9 again. People keep asking, “Have you tested the heated fruit with the CGM?” So I need to. Because basically, what happened was I was so freaked out by that, I immediately put on a CGM and I immediately stopped cooking the fruit. And so I was too scared to cook the fruit at at all so do it-- Now [laughs] that we're back to normal, I need to do a round with a CGM and just have one night. I also don't want to bring back that habit though, because [laughs] I don't think I will. It's been so eye opening. So I don't know, just stories like that. 

Kara Collier: That's fascinating. I have a similar-- Well, not as similar as in-- it's different, but I had my A1c creep up, but my diet was exactly the same, and I put a CGM on, and my average glucose was higher. I was like, “Oh, the data is right. What is going on?” Tested this, got it back down. But what I realized is so I live in Phoenix, Arizona, and it gets nice and toasty here in the summer. It gets really hot. And so in the summer, I stopped going on walks throughout the day pretty much because you're melt when you go outside. I was still going to the gym, I was still doing intense workouts, but I wasn't moving at all in between my step count, had basically plummeted to nothing and it caused my average glucose to creep up a little bit and my A1c to creep up a little bit. I just wasn't really getting back down into those normal levels. It was just a lot more sedentary throughout the day. Baking that back in, finding ways to move when it was still hot, but just being more mindful and intentional about finding ways to move if I wasn't going outside brought it back down into normal, but very interesting too. 

Melanie Avalon: I love that so much. Yeah, it's like you're like a detective, his magnifying glass. It really helps you find what's going on. I'm curious with the app. Okay. Because for friends, the app has so much data and information in it. Does it have anything making comparisons for the history of your different sensors that you've done as far as how it correlates to time of year? 

Kara Collier: Yeah. So we have an insights tab where you have all of your nerdy analytics and statistics all about your glucose data. So that's going to show your average, that's going to show your peak, it's going to show your glycemic variability. And then you can also compare it to previous time ranges. So you could look at what-- If you just finished 14 days, and let's say the first seven days, you did your normal routine, and the second seven days, you switched things up, you could compare the current seven days to the previous seven days, or you could compare the current month to a previous month. And right now, what we just have is set where it's like the last three months as compared to the three months before that. But what we're working on that will be coming soon is more flexible comparison ranges where you could pick like this exact date range compared to this exact date range. So that will be coming soon. 

Melanie Avalon: Awesome. If I were to theorize or hypothesize about mine, I would think that mine is consistently lower in the winter because of the cold exposure. Have you seen any trends with people, or with NutriSense with the data in the app about weather? Yeah, weather. 

Kara Collier: Yeah. We tend to see higher values in the summer for multiple reasons. I think one is hydration tends to be more of an issue in the summer. The other is that people tend to eat higher carbohydrate in the summer than the winter. You've got all the fruit is in season, which is great. I'm not anti-fruit. It sounds like you're not either. But it can be easy to get carried away sometimes, especially if you're not mindful about set meal times. So people, I think, tend to eat a little differently in the summer. Then yeah, the hydration thing, so on average. But at the same time, we do see that. The highest glucose values tend to be around the holidays, which tend to be more stacked in the winter. So don't let the holidays deviate you from your goals. 

Melanie Avalon: I believe that. I've also been very impressed with the app, just, again, how much data there is and the features with those cryo spikes. Once I realized that I was fairly certain they were not real [giggles] that they were just from it being cold, I asked in the app how to get rid of them. Basically, you can go in and you can actually remove a data point. So that was pretty helpful. So we got quite a few questions because I think people are just a little bit overwhelmed by the idea of interpreting all this data. So I'll read a few of the questions. Marla says, “If I'm having to pay out of pocket, what is the best as far as affordable and easy to understand? I'm worried I'll pay for it and have no idea what all of the information means or how to use the data to help myself?” Nancy said, “I have a CGM, but I'm finding it hard to interpret and make use of my readings. Where can I go for support? Are there Facebook groups or functional medicine professionals who can make sense of patterns?” 

Okay. So people who are overwhelmed about-- Actually, I'll read this one. And then also Nancy said, same Nancy, she said that, “She's not been able to discover any patterns or behaviors impacting her glucose readings.” As a low carb eater, she says that, “Her swings have nothing to do with food, but maybe it's exercise, sleep, stress, or other inflammation or illness.” So people who are overwhelmed by the idea of interpreting this data, how can NutriSense help them? 

Kara Collier: Sure. So I'll talk at a high level of how to think about interpreting your data and then specifically what we do at NutriSense to help with that, because maybe you have a sensor and you're not going to use NutriSense. Again, I want you to make the most of the CGM data whether you're using NutriSense or not, because as we both believe it's so powerful. So if you're just looking at the data, you have no idea what to make sense of. I would really think about it in three categories. One is, what is my glucose doing in the fasted state? We really want our glucose levels to below 90 when we're fasted. Ideally closer to that in the 70s, 80s. It's okay to be in the 60s or even lower if you're not having any hypoglycemic events. So many people who are really low carb or doing a lot of fasting and entering ketogenesis will be in those lower values.

So one thing to look at is what's happening when you're fasted. A little bit of fluctuation during that fasted state is totally normal, but you will probably see deviations from day to day and you want to look at that. So let's say, overnight, your glucose values were in the 70s today, but the night before they were 110. So looking at what did I do differently that day versus this day. The second thing you want to look at, are those average glucose values, as we mentioned, really keeping them below 105? You might have good fasted glucose values and never be spiking too high, but your average might be always a little too high, what's happening overall that 24-hour view. 

Then the third component you really want to drill into is what's happening when you eat or when is your glucose spiking. And so for a nondiabetic, we really want to keep glucose below 140 as that upper threshold. We want our bodies to be able to recover from a glucose spike and come back down to pre-meal glucose values within usually three hours or so of eating. If you're doing an eating style like yours, where you're eating one meal a day and it's a much higher volume of food, sometimes it might take maybe closer to four hours, and that would be expected because it's more food, but it's going to be counterbalanced by the point that the rest of the day is very, very low and you're not having those peaks and values throughout the day. 

Melanie Avalon: Okay. You answered my question. I was going to ask that. [giggles] 

Kara Collier: [giggles] Yeah. And so those are really what to drill into if you're not sure. And then with the NutriSense app specifically, there're two types of people. There's the person who's like, “I want to know if this is good or bad. Am I okay?” And then there's the other person that's downloading their data, and doing Excel models, and logarithm, mathematic equations to know every deviation. They're really nerdy data people. And so if you really just want to get a general idea, we give you a daily glucose score that takes all of the most important components and scores your day on a 1 to 10 scale, so that you can get a really quick at a glance idea of how your glucose values looked that day. We do the same with meals. So we give meal scores. So if you log a meal in the app, you'll also get a score in that two-hour window after you've eaten of how your glucose response was to the meal. Then, as I mentioned, we have a more detailed view of all of the analytics on a separate tab where you can see the trends, you can see-- it'll tell you that your peak glucose is trending 10% higher this week than last week, it can help you drill down. 

The final thing that we do at NutriSense is we also provide you access to a dietitian. This is a dietitian who has seen a lot of other glucose, data who is well versed in all of the various dietary and lifestyle strategies to help support good glucose values. If you have any questions, you're like, “Why is my glucose doing this? What does this mean?” Those are perfect questions to send over to our dietitians. They're there for as much or as little support as you might like. Some people message their dietitian all day, every day, and some people use them very minimally. So they're there to help you navigate, both interpreting the data and also then creating ideas on how to improve the data or what to do differently, creating goals, holding yourself accountable, so to speak. 

Melanie Avalon: I love it so much. Yeah, I've been personally highly impressed with the dialogue with the dietitians. I personally don't use it as much. I more just go on my own and interpret it. But I've had a lot of friends use it and have told me that their favorite part of the app was that access, like, being able to talk to somebody almost in real time. You can log into the app and chat, and they help you ascertain what's going on and how you might make changes to address it. Do you have thoughts--? This is just my question. I think I asked you this on the other show. But some people doing low-carb diets will have higher resting blood sugar levels. Actually, I'm having Dr. Gabrielle Lyon on the show pretty soon. And in her new book called Forever Strong, she actually talks about this, how she typically sees higher blood sugar levels in people on lower carb diets. But she doesn't think it's an issue. What are your thoughts on that? Does the body know or care if the blood sugar is coming from food versus gluconeogenesis in the liver? 

Kara Collier: Yeah, it's a great question. So it is a phenomenon that we do see typically when people are following very low-carbohydrate diet for an extended period of time. So we usually don't start to see this happen unless someone's been doing it for at least a year. And really what's happening here is adaptation. The body is realizing that it's not getting a lot of glucose from food, so it raises glucose levels a little bit endogenously on its own to make sure that some of these more glucose sensitive organs have that steady stream of glucose available. So usually, what we'll see is that fasted glucose values are a little bit higher. Sometimes they might even be in the high 90s, close to 100, but their glucose levels are really stable throughout the day. There's basically no variability, no ups and down, no spikes. 

And so for me, there's very little research out there to actually pinpoint whether this is a good or a bad thing. But my interpretation of this is that it's most likely perfectly fine, but the things that you would want to double check is, first, to make sure that if you get a fasted insulin level that it is also low. Because for this, we would expect insulin to be low. If it's high, then that means you have an over availability of energy if insulin is high and glucose is high. So insulin should be low in this instance. We still want to make sure that your average glucose values aren't creeping up above that 105 range. So if you're starting to see average glucose values at 110, 115, that's when I start to get a little bit concerned that maybe it's too high, because at that point, you still are having a lot of glucose in circulation that's going to lead to higher glycation events, and that can potentially have negative downstream effects. I have very, very rarely seen that average glucose gets that high in that instance though. So those would be the two kind of parameters I would make sure are still okay. 

Melanie Avalon: Awesome. Is insulin also an interstitial fluid? Like, is there the potential of an insulin monitor, continuous insulin monitor? 

Kara Collier: There're talks that maybe one day, it'll be possible. It's much more complicated because even the lab draw to get-- We don't even have a finger prick insulin because it's a lot different to measure it than glucose is. Glucose is a much more simple metabolite where insulin is a hormone. I have heard that it's possible and it might one day happen, but I would say it's not in the very near future at least.

Melanie Avalon: I got really excited. I didn't realize that there was an HbA1c, like, blood glucometer that you could do at home.

Kara Collier: Which is really interesting. Yeah.

Melanie Avalon: For listeners. I had James Clement on my other show. He wrote a book called The Switch. I totally forgot about this. There was one time where I got some lab work back and my HbA1c was high a little bit, and I was telling him about it, and he sent me one in the mail. I was so happy. I had no idea that they existed. I pulled it out when I had that 5.8. It was a little bit sad, but we fixed it. So yeah. Actually, Caroline wanted to know, “Is it more important to track insulin than blood glucose as I've heard on some podcasts?”

Kara Collier: I think insulin is incredibly valuable. If a day comes where we get the 24/7 insulin view, it's going to be a game changer. But right now, what's mostly practical at this point in time is to be able to get a fasted insulin level, which I really do recommend people do, just to check that that's good. If you are doing the CGM and your glucose readings are in good place, I'm going to put money on the fact that your fasted insulin levels are also good. But what is really useful is that postprandial or 24/7 view of insulin. But it's not really practical to do that for most people at this point in time because you would need to convince somebody to--

Every once in a while in very more expensive concierge medical clinics, they'll do the oral glucose tolerance test with both glucose and insulin. So for that, you drink a bunch of sugar and you sit there for two hours or three hours, and they draw your blood at every 20 minutes, 30 minutes. That's pretty interesting. But again, that's not practical for most people. So at this point, I would say our best combination is to do that fasted insulin once a year with your regular lab panel and do the CGM every once in a while.

Melanie Avalon: Awesome. Well, speaking of postprandial, so earlier, you were saying the two main things to look for would be swings and then that postprandial blood sugar spike after your meal. Mary Jane wanted to know, “Besides big spikes or big drops in blood sugar, what are other patterns of concern to look out for?”

Kara Collier: Of course, the big drops and the big spikes. The other is if you see a really slow, gradual increase in your glucose and it takes a really long time for it to come back down. So we'll typically see this type of pattern in either individuals who are insulin resistant or if you could be metabolically healthy and you have this pattern to something that's really high fat, really high carb. So I'm talking like cheeseburger with French fries and a milkshake. That kind of meal, even in a metabolically healthy person, is going to have your glucose rise really slowly. You're probably not going to see a sharp increase because there's so much fat that's slowing the digestion down. So three hours later you might see the glucose peak and then you might not see it come back down for eight hours. That even if you don't ever reach 140, which you probably won't. A lot of people look at that and they're like, “Oh, maybe that meal wasn't so bad because my glucose never went above 120.” But if you see the curve, it took eight hours for your body to really process all of that and you were probably hungry three hours later though. So then sometimes people are eating again while they're still coming back down.

So a slow return back to baseline is also something you want to look at. That big dip, the reactive hypoglycemia is another thing. And then just those big swings. Even if you're never reaching 130, 140, if you're having a lot of that variability, so that up and down momentum, that's a pattern we want to monitor. There's actually research to show that higher glycemic variability creates more oxidative stress and inflammation than sustained stable high glucose levels, which is really interesting. Yeah. So those big swings are potentially worse than if your glucose was just high but stable. So very interesting. 

Melanie Avalon: Is that with the same area under the curve, total blood glucose between those two situations?

Kara Collier: Yeah. So between the two, you could assume that they're having potentially the same average glucose, but one is high and flat and then one has lows and highs, but is up and down. That up and down, even if it's the same average glucose is a lot more detrimental to our health.

Melanie Avalon: Wow. That's really interesting. Margaret wants to know, speaking of a stable blood sugar level, she says, “If my blood glucose is shown to be relatively stable with no major spikes with the CGM, what is the next step to assess if weight loss is the goal?” So where do we go from there, if it is stable? 

Kara Collier: Yeah. If it is stable, that's great. We also want to make sure it's in that optimal fasted range. So for some people, maybe it's stable, but it's resting at 110 or so. So you really want to look at what it looks like in that fasted state and assess that. And then if all of that looks good, then there might be other things at play outside of glucose that might be hindering your weight loss. So that's where it's important to know that glucose is really insightful. That was a point I was going to make when we were talking about interpreting the glucose values of-- You said that somebody said their diet never causes their spike, but sometimes it's stress or something else. The really useful thing about glucose is not only does it fluctuate in response to our diet, but it also fluctuates in response to our level of activity. In my example, my glucose was creeping up because I was becoming more sedentary, but it also responds to stress, both psychological stress, but also physical stressors like being sick or being in a high pollution area, things that cause our body to be put in that stress state. And then it also responds to our sleep quality and quantity. So it gives us this good overall view of our health and where to pinpoint. But at the end of the day, it's not the only metric that matters. 

So sometimes we can get glucose in a really good spot, and maybe we still need to address other things that aren't reflected in your glucose values to help take weight loss to the next level. And of course, that might end up being really personalized depending on the person. But I would say, majority of the time, if getting your glucose values to a good place will really accelerate weight loss for most people because it helps to unlock some of that more fat burning state, but it also, again, helps people be consistent with the habits that they want to do. It holds people accountable more and we know when we're consistent and we're doing the things that we know work for us, that's when we really start to see results. So that tends to be one of the biggest benefits for long-term weight loss and keeping the weight off is that accountability element.

Melanie Avalon: I could not agree more because I especially get asked all the time. I'll have a lot of new listeners to, both this show and my other show, and everything. There're so many like ways to go when you finally fall into this health world. I actually got a message on Instagram, a DM, yesterday, I think, and she said that she just found me and she found all my stuff and where to start. Then she actually said in the message, she said, “Would a CGM be the best place to start?” I was like, “Actually, yeah. That's one of the best ways,” because you just immediately can see-- 

Kara Collier: You're going to get that view into the most important element. 

Melanie Avalon: Yeah. Like you said, it's not just food. It's so many other things beyond that. Okay. Two other really quick questions about the data specifically. So Jill said that-- This is interesting. She said, “She heard some discussion of the dawn phenomenon and she heard that it's like a report card of yesterday's activity. How true is this?” And then she says, “CGMs are such a great way to see the detailed data.” Have you heard that before? 

Kara Collier: I haven't. I would say that overnight glucose values and those morning fasted glucose values are indeed a report card for the day before, but I would separate that from the dawn phenomenon. So the dawn phenomenon is a very natural response our body has, where we tend to have a little bit of a glucose spike. I wouldn't even call it a spike, a glucose rise when we wake up. I describe it as our body's natural alarm clock. You wake up and you have a surge of hormones that help wake you up, get you going for the day. And typically, that comes with a little release of glucose value or glucose levels, and then usually it comes right back down. So for a normal person, this might be a rise of 10-ish points. And then within an hour, it's back down to baseline values. This is really normal. 

What you'll see with a diabetic is that because their body is no longer insulin sensitive, they have the same dawn phenomenon response, except their glucose rises maybe 50 points and it stays high. It never goes back down. So this phenomenon was really created in response to looking at diabetics glucose values because this is a problem for them. They have really high morning glucose values despite doing nothing differently, basically. But in healthy people, we see a really minor one and it's not a big deal. But when you're looking at your fasted glucose values and your overnight glucose values, really what it's typically reflecting is what you did the day before. So if you had maybe a different meal than normal, maybe you had like a dessert with your dinner the night before and you don't normally do that, you'll probably see that reflected in those morning values the next day. Let's say, you had a couple more glasses of alcohol than you normally do. You'll probably see that the next day. 

The other main reason that we might see fasted glucose levels drive up, well, also sleep quality. So I guess, that's reflected from the previous day. But another big one is just stress levels. So if we're feeling like nothing has changed in our routine but our fasted glucose levels are creeping up, it's typically stress, because that surge of cortisol and that stress response is telling your liver to dump more glucose. And so we see those glucose values rise despite no change in activity levels or our dietary levels, then we can usually pinpoint that to stress. 

Melanie Avalon: Gotcha. Yeah. We hear the word stress and it can seem very vague. Of course, everybody's stressed, but it literally can have this hormonal effect that [giggles] is raising our levels. So as far as seeing the spikes, so Xena says, “What to do with the information? Does that mean cut the food out completely if it spikes?” 

Kara Collier: Great question, because the answer is no, not always, especially, if it's like a nutrient dense, healthy food. So let's say let's take the example of-- Your example is great. Let's say that you're eating more like cooked fruit and you're having a big glucose spike and you're like, “What should I do with this?” Again, you can troubleshoot this yourself. But this would be a great question if you are working at NutriSense to ask your dietitian, and we'll experiment with that. So maybe the suggestion might be to try it in its whole form, which happens a lot. So an example might be somebody who's drinking a smoothie version of that fruit or they're juicing their fruit. So then we might recommend to just eat the whole fruit and see how that goes. 

Another really useful tip is typically to make sure you've eaten protein and some fiber. But typically, protein is the best in this situation to eat some protein first and then the fruit, and you'll likely see your glucose response improve. Another strategy is to make sure you're getting movement in to help mitigate some of that response. So those are all helpful things to try if it's a food that we believe is healthy, nutrient dense, and also a food that you really enjoy. So if you're like, “No, this is my favorite food ever. I don't want to get rid of it.” Usually, we can find a way to make it work. But if it's something like, let's say you had a candy bar and you had a glucose spike, we could probably mitigate it a little bit, but it's also not good for you, not nutrient dense, not adding any value. So most likely, yes, we would like to just remove that from that routine. But for a lot of things, there is actually quite a bit we can do. 

Melanie Avalon: Going back to something you were saying or we were both talking about earlier about valuable information in the moment, but then also how you remember it, I still-- Because I think there's been one time when I was wearing a CGM when I ate really processed food. It was still paleo, but it was still gluten free and all the things, but it had a lot of natural sugar in it. I don't know why. I think I had like a random craving for cereal. And so I got one of those gluten free cereal things and I ate a lot of it. It spiked so high on my CGM, and that haunts me to this day. [giggles] I'm like, “I know now, like, what that's actually doing to me.” Maybe there's a time and place where I'll be in a situation, and it's my birthday, and the cost benefit of life, like, it's worth it in that moment. I think you can do that and you can still have the agency and the knowledge. I think it's just about taking responsibility for yourself and knowing what's valuable. 

Kara Collier: Yeah. Mindful of those tradeoffs. When you do know that information, you're geared with it, then you can make the really intentional decisions. It's not just like, “Oh, I'm just eating this because it's in front of me.” A lot of times, we'll have people who work in offices where there's always some sort of treat for somebody's birthday. There's cupcakes, there's donuts, there's whatever. When before maybe you would mindlessly have one, now it's like, “I know what that does and I'm only going to do it if it's really, truly worth it.” So it's like making sure it's worth it, because life is worth living and we don't have to be perfect all of the time. But I think it's about being geared with the information and then really weighing the pros and cons and making a decision that feels right for you. 

Melanie Avalon: I cannot agree more. None of the questions today, I don't think mentioned it, but people have said before that they're hesitant to get one because they just don't want to know. Basically, I just find it so eye opening and empowering, so that you can really make the decisions the majority of the time that will best suit your health and then have those moments where if you do choose to do something that you know might not look the best on your CGM, at least you're aware and it's in the context of the rest of the time when you can be taking more agency. So as far as getting a CGM, we did have questions about getting one and the price.

So Wendy wanted to know, “Why are they so expensive and why would you need one if you have no need for one?” Although I think we've talked a lot about that second part. Joy wants to know, “When will they become more affordable?” Jackie wants to know, “What is the initial cost of the CGM and the continuing cost for supplies and the membership? Is it worth it if you're not diabetic and at a normal BMI. Could it be a benefit for a healthy senior citizen? How does the NutriSense program work as far as people getting a CGM, and the affordability, and the pricing and the access? How does that all work?” We do have a code for listeners that we can share as well. 

Kara Collier: Yeah, absolutely. So in terms of just how it works, you would sign up on our website, and you fill out a quick health questionnaire and you pick which plan you want to do, so I'll walk through that. But then you don't have to do anything else. So we take care of all of the getting the devices, shipping them to your doors. Based off of the subscription you choose, they would come to each month, and then you have lifetime access to the app and your data. So you put the sensors on at home, you use the app, and then you chat with the dietitian through the app as well, and then you don't have to do anything. And our options, we have that month to month, no commitment, like I mentioned. So you could do just one month. That's the shortest time period. And we have all the way up to a 12-month commitment. Month to month is the most expensive. It's $350. And then the 12-month is the cheapest and it's $199 a month. And then we have plans that vary in between. 

Why it's so expensive? We would also love for it to be cheaper. My goal as well is to have every single person have them at least be able to use it at least once and get that data. But the hardware right now is still just costly. The devices themselves are just more expensive, but they have already trended down in cost since they've been available over the last 10 years or so. So 10 years ago, they were hundreds of dollars apiece, and now they're significantly less than that. So we do anticipate that with more demand, they'll continue to drive down prices. We also anticipate that each sensor will continue to be able to last longer, which helps as well. They used to only last-- the very first version of these sensors only lasted three days, and now they last 14 days. So they will get cheaper, they'll last longer, they'll be smaller, and they'll just continue to get better over time, and we'll be able to drive down those prices. We will be rolling out within the next few months, actually, the kind of membership bring your own sensor option. So this will be a onetime fee. And then if you have sensors of your own, you can use our app and access all of that information as well. 

Melanie Avalon: Awesome. And for listeners, they can actually go to nutrisense.io/ifpodcast and use the coupon code, IFPODCAST, and that will get you $30 off as well. So we are super, super grateful for that. Well, this has been so amazing. I cannot thank you enough, Kara, for everything that you are doing with this company and making this accessible to people. I'll just share one last quick anecdote. I had my own experience. Something I really love testing on the CGM was I have my AvalonX supplement line, and I was historically taking berberine for blood sugar control. I don't want to say so much control as, I guess, blood sugar optimization. 

In any case, I honestly thought when I made my version that I wouldn't see any difference, but when I did, I made my own version of it and I saw massive changes on my CGM as far as the effect that it had on my postprandial spike. That was really exciting. And then I heard that from people as well. That's something that honestly, I just never could know if I didn't have the CGM. So it's just been, for me, personally so eye opening in so many ways with that, with my daily diet, with the HbA1c issue, with so many things. I hear testimonials from people all the time. And so, like I said, I cannot recommend enough that people get one of these. I can't thank you enough for making it so, so accessible and so easy to interpret and understand. It's just awesome. You're changing the world literally. So thank you so much for all that you're doing. 

Kara Collier: Oh, yeah, absolutely. I appreciate your support. Yeah, our goal is really just to help people take control of their health, and learn this information, and really just better themselves, which ends up bettering everyone else as well. So I'm going to have to check out your supplement as well. I'd be super curious to try it. Sounds awesome. 

Melanie Avalon: Oh, I will send it to you, most definitely. 

Kara Collier: That would be great. That'd be so fun. 

Melanie Avalon: It's so exciting because I had that experience and then so many people have told me that as well, they would check it on CGMs. I was like, “Ah, this is fabulous.” If you're open to it, I'd love to have you back more regularly because this is just so important and wonderful and I can't wait to air this. I'm so excited. Okay, well, thank you so much for your time, Kara, and I will talk to you very soon. 

Kara Collier: Yeah, absolutely. Thanks, Melanie. 

Melanie Avalon: Bye. 

Thank you so much for listening to The Intermittent Fasting Podcast. Please remember everything we discussed on this show does not constitute medical advice and no patient-doctor relationship is formed. If you enjoyed the show, please consider writing a review on iTunes. We couldn't do this without our amazing team, administration by Sharon Merriman, editing by Podcast Doctors, show notes and artwork by Brianna Joyner, transcripts by SpeechDocs, and original theme composed by Leland Cox and re-composed by Steve Saunders. See you next week.

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