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This week on the podcast, Mikki speaks to Dr Philip Prins, researcher and expert in exercise metabolism, about a new paper examining one of the most widely accepted ideas in sports nutrition: the role of carbohydrate in endurance performance.
For decades, the dominant narrative has been that muscle glycogen depletion is the primary cause of fatigue during prolonged exercise, and that high carbohydrate intake is essential for sustaining performance. But Dr Prins and his colleagues revisit the evidence and ask a deeper question: is that explanation actually supported by the data?
In this conversation, they explore the physiology of fatigue, the often-overlooked role of blood glucose and liver glycogen, and the phenomenon of exercise-induced hypoglycaemia as a potential driver of performance limitation. They also discuss how relatively small amounts of carbohydrate can improve performance, why higher intakes don’t always translate into better outcomes, and what this means for current high-carbohydrate fueling recommendations.
Along the way, Mikki and Dr Prins unpack fat oxidation in low-carbohydrate-adapted athletes, the importance of individual metabolic differences, and whether fueling strategies for endurance athletes may need to be far more individualised than current guidelines suggest.
This is a fascinating discussion that challenges long-held assumptions about carbohydrate, fatigue, and how athletes should actually fuel for performance.
Dr. Philip Prins is an Associate Professor of Exercise Science. Dr. Prince earned a B.S. in Kinesiology as well as an M.S. in Exercise Science from Georgia Southern University, and a Ph.D. in Exercise Physiology from the University of Pittsburgh. His research focuses on, among other things, the practical impact of lifestyle on metabolism and how metabolism impacts health, disease and performance outcomes. Among his many areas of expertise are nutritional ketosis, metabolic responses to exercise, and sports nutrition.
Dr Prins can be found here: https://www.gcc.edu/Home/Academics/Faculty-Directory/Faculty-Detail/philip-prins
Dr Prins Researchgate: https://www.researchgate.net/profile/Philip-Prins
Previous podcasts https://podcast.mikkiwilliden.com/190 and https://podcast.mikkiwilliden.com/348
Creators and Guests
What is Mikkipedia?
Mikkipedia is an exploration in all things health, well being, fitness, food and nutrition. I sit down with scientists, doctors, professors, practitioners and people who have a wealth of experience and have a conversation that takes a deep dive into their area of expertise. I love translating science into a language that people understand, so while some of the conversations will be pretty in-depth, you will come away with some practical tips that can be instigated into your everyday life. I hope you enjoy the show!
00:00
Hey everybody, Mikki here. You're listening to Mikkipedia and this week on the podcast I bring back Dr. Philip Prins who is a researcher and expert in exercise metabolism about a new paper examining one of the most widely accepted ideas in sports nutrition, the role of carbohydrate in endurance performance.
00:24
For decades, the dominant narrative has been that muscle glycogen depletion is the primary cause of fatigue during prolonged exercise and that high carbohydrate intake is essential for sustaining that performance. But Dr. Prins and his colleagues revisit the evidence and ask the deeper question, is that explanation actually supported by the data? And in this conversation, which I'm super excited to bring to you, we explore the physiology of fatigue
00:53
the often overlooked role of blood glucose and liver glycogen, and the phenomenon of exercise-induced hypoglycemia as a potential driver of performance limitation. We also discuss how relatively small amounts of carbohydrate can improve performance, why higher intakes don't always translate into better outcomes, and what this means for current high carbohydrate fueling recommendations. Along the way, we unpacked
01:19
fat oxidation in low carbohydrate adapted athletes, the importance of individual metabolic differences, and whether fueling strategies for endurance athletes may need to be far more individualized than current guidelines suggest. This is a fascinating discussion that challenges these long-held assumptions about carbohydrate, fatigue, and how athletes should actually fuel for performance. And if you recall,
01:44
Last time I spoke to Philip, which was last year, episode 348, Philip did allude to this new review paper that looked at over 600 papers and really draws together the evidence and this is that paper that we're chatting about today. So this conversation I feel is a long time coming and definitely ruffled some feathers in the sports nutrition world. For those of you unfamiliar with Philip or haven't yet listened to his previous episodes,
02:12
that's episode 190 and episode 348. I've linked them in the show notes. Dr. Philip Prinz is an associate professor of exercise science and he earned a bachelor of science in kinesiology as well as a master of science in exercise science from Georgia Southern University and a PhD in exercise physiology from the University of Pittsburgh. His research focuses on, among other things, the practical impact
02:39
of lifestyle on metabolism and how metabolism impacts health, disease and performance outcomes. Among his many areas of expertise are nutritional ketosis, metabolic responses to exercise and sports nutrition. And I have links to Philip's academic page, his research gate page, and also the study that we're chatting about today, the review that was authored by Philip alongside our lead author, Professor Tim Noakes.
03:09
and Dr. Andrew Kutnick who is also a former guest on the show amongst others. So if you're interested in anything related to sports nutrition or health and metabolism, I think you're really going to enjoy this conversation. Before we crack on into it though, I would like to remind you that the best way to support this podcast is to hit the subscribe button on your favorite podcast listening platform.
03:31
and that increases the visibility of Micopedia and amongst literally thousands of other podcasts out there. So more people get to hear from the guests that I have on the show like Dr. Philip Prince. All right guys, enjoy this conversation.
03:52
Dylan, thank you so much for speaking to me this morning for the third time actually on my podcast, which is outside of some of my good friends. are very few guests I've had on three times. It's just because you continue to release research, which I think is so important and it does seem to fly in the face of what most people understand. So I'm so pleased to get the opportunity to chat to you. Well, I appreciate it. Thanks for having me back again.
04:21
You are welcome. And I was saying to you just before we kicked off that like your tomb of a paper, like I printed it out and was reading through it, is like massive, it's like a thesis. It is like one of the three things that has blown up the internet over the last month. 2026 has really started off with a bang. Yeah, I'm glad there is such a significant interest in that paper. I mean, you never know, right? When you do a study or in this case, a
04:49
a massive review how much interest there were actually be. I you can hope that other people would also be interested in your work. yeah, I mean, we think this is quite significant and much of the praise goes to Professor Tim Nokes since he was the lead author. And he was the person who spent most of his
05:14
time working on that big review paper that was just published a couple weeks ago in the journal Endocrine Reviews, right? He's a special person because it takes a special person to review about, you know, 600 studies. So if you go to the actual paper and go to the references, that's, I mean, it's really the most comprehensive piece of work as it pertains to carbohydrate supplementation and performance and metabolism that has ever been done.
05:44
and published. mean, it took about four uh or five years um to actually look comprehensively uh at hundreds of studies. mean, over 160 of them are just purely performance-based studies. So it's over the last 100 years. this century of literature has been carefully evaluated um in this uh latest publication.
06:14
And I find it so interesting. And I've got like a lot of questions that that hopefully we'll get to a lot of them just to sort of lay it out. And of course I'll put a link to the paper in the show notes for people to be able to read themselves. But what I find fascinating, Philip, is actually, it's just the reaction from so many people who are so, who feel like it's almost like you've, I don't know, told them that.
06:40
you've told a whole religious group that their God isn't real. I don't know. There's so much pushback. And I do wonder how much of the pushback comes from a misinterpretation of what they think the paper is saying. Because a lot of the feedback that I've seen is like, you're saying that carbs, I don't know, that carbs don't help performance. And then they've listed athletes and papers and stuff, which
07:06
clearly show there's some performance benefits. So is there a misunderstanding or misinterpretation of what the paper is actually trying to show? Yeah, I mean, so obviously once the paper went live a couple of weeks ago, I mean, there was significant interest, especially if you go on social media. So our colleague Andrew Kutnik did an amazing job at putting all the different posts together um and just making sure
07:35
uh to kind of maximize the reach of the paper. And obviously there's been, um the response has been very favorable from most individuals. But as you mentioned, sure, I there are obviously definitely some um who have different views and opinions on the topic. I think a lot of it goes to um people actually not reading the paper. So kind of just that visceral response. uh
08:05
it is contradicting uh their own beliefs as it pertains to sports nutrition or just maybe nutrition in general. so just saying all kinds of silly things without actually reading the paper. think anybody um who maybe have different views or opinions on the paper, the first thing you should do is probably read the paper. That would be helpful.
08:32
But yeah, mean, it's the paper is ultimately, um if you do read it, if you do understand what we are saying, um we are proposing a paradigm shift, right? And those aren't easy, right? When you're proposing a paradigm shift, completely different way that you're viewing a specific topic, in this case, sports nutrition, um you know, that's not easy for a lot of people to accept.
09:00
Yeah, no, I appreciate that. And Andrew, I think, did an amazing job of fielding lot of the um objections to maybe the premise of the paper or what people thought the paper was about. uh But also, mean, he's very good also at saying, look, this has generated a lot of really good discussion as well. I think that's what these papers are designed to do, isn't it? Yeah, absolutely. And I think
09:28
At least from what I saw a little bit on social media, I that I spent a large amount of time there, but um I did see a lot of discussion as regards to diet superiority, right? This whole idea about low carb and high carb diets and it's like, well, hang on. I don't think the paper really touched on that topic that much.
09:52
uh It's not like it's a review. It's not a meta-analysis looking at low-carb and high-carb diets, And which one results in more superior athletic performance. So for some reason, the conversation ended up steering in that particular direction, maybe because some people uh assumed, right, these are the authors who typically do this type of research. So therefore, the paper must be on this particular uh topic. yeah, that's if you...
10:22
if you uh get the paper or even if you take it, because it's too long and you want to read the whole thing and you put it into chat GDP or whatever AI system you want to use, it's not about diet per se. It's not necessarily about which low carb or high carb diet is ultimately going to improve performance. I we can have those conversations since we've done those studies, but it does present ultimately a paradigm shift in terms of the way
10:51
we view uh nutrition, sports nutrition in general, especially fueling strategies during exercise. Is it best to fuel the muscle with carbohydrate, right? Or is it better to fuel the liver, right, with carbohydrate?
11:18
You know, is fatigue more, is it more centrally mediated? Is it more peripherally mediated? Those are the questions that you're, that the paper is sort of more designed to answer, isn't it, to review? Yeah. Oh yeah, absolutely, Yeah. So Phillip, then actually, and I guess that does bring me to my first question. So people are out there saying that you guys are suggesting that
11:45
You don't need to have 150 grams of carbs an hour. It's going to hinder performance. It's going to harm performance or whatever. what is the main question you are actually trying to answer with review? Yeah, I mean, the core question is really, does carbohydrate improve especially endurance performance by supplying the muscle just with more fuel, right? So what we term the large glucose fuel or by rather preventing exercise-induced
12:15
hypoglycemia, right? uh The small glucose pool, right? The glucose that's in the blood and the liver. That's really the core question here. And the motivation is, decades of studies that report hypoglycemia at exhaustion, yet uh interpretations focus almost entirely on muscle glycogen. uh
12:44
Basically, if you go look at our, if I were to kind of just back it up a little bit, our research over the last 10 plus years has focused on models, has focused on mechanisms. And this goes back to this other question that you were asking about the paper and how people are viewing and interpreting the paper and maybe some misconceptions there. Because a lot of times when people are looking at this type of work,
13:13
they're just looking at maybe, you know, what did the diet do? ah When instead looking at mechanisms, right? Because ultimately what we've done over last 10 years, we've used different dietary approaches to study different uh mechanisms and different models. And obviously, especially in the field, in this field of exercise science and sports nutrition, we know that there's this very high carbohydrate mentality.
13:42
And but that goes back to different models and mechanisms. So obviously in some of the previous podcasts that I've been on with you, we've talked about some of those different mechanisms and models, especially the crossover concept, right? Or this whole glycogen centric view of exercise performance, right? This belief that muscle glycogen is obligatory, it's essential when it comes to especially endurance exercise performance. So those two models, right?
14:11
One of them, the crossover concept is basically saying that uh carbohydrate is essential for your higher intensity exercise performance. But then the other one, muscle glycogen, we go, well, that's obligatory, especially for your longer duration exercise performance, because once your muscle glycogen gets too low, your fatigue, those fatiguing symptoms goes up and you get tired and you want to slow down or stop there as a result.
14:38
So actually what we've done over the last 10 years is we've studied these different models. We've done studies where we um specifically put athletes on a low carbohydrate, on a ketogenic diet, we um increase fat oxidation. So that's the idea. We're significantly increasing rates of fat oxidation by putting athletes on these diets and then seeing, well, is it not possible?
15:04
that they can perform high intensity exercise. We've done five kilometer time trials, we've done one mile time trials, we've done repeated sprints, all of them well above the crossover point. Right, crossover point is usually about 60 % for, of the ultimate for most athletes. So all those studies have gone well above that and we've shown performance is not impaired, meaning fat is not an inferior metabolic fuel. It is able to actually support higher intensity.
15:31
uh exercise performance, right? It's able to shift that crossover point uh to the right. And then we've also done studies looking or more challenging this more glycogen-centric view of exercise performance, right? Because all that you, basically what you're doing there is again, now you're putting athletes on a low carb diet, but because that is going to lower their muscle glycogen. So, you know, usually, I mean, if an athlete goes on a low carb diet, their muscle glycogen is now 40%, 50%.
16:00
lower in most cases. It's significantly depressed. And so now the idea is, now that I'm on a low carb diet, my muscle glycogen stores are significantly lower. Now if I do, especially some form of endurance based exercise, immediately right from the start, my muscle glycogen levels is going to start to go down. So which means, according to that particular model, once my muscle glycogen levels gets too low,
16:26
I'm going to hit the wall, so to speak, right? The symptoms of fatigue is going to become accelerated and I'm going to want to slow down or stop as a result. So we've done studies where we've actually done repeated sprints and because you can also repeat your muscle glycogen fairly rapidly by doing these very high intensity exercise. And the idea was there, you know, maybe here by the halfway through third, fourth, fifth interval.
16:54
now that they're on the high carbohydrate, sorry, on the low carbohydrate diet, they would have depleted their muscle glycogen stores uh quite significantly and performance would have been impacted. Admitted it wasn't. But then we also did um studies where athletes are now cycling for a couple of hours. So if they're cycling for a couple hours, but with starting off with low levels of glycogen within the muscle, according to that theory, their performance should have been negatively impacted. So it's all these studies we've done over the years.
17:24
looking at different models, different mechanisms, showing that once we put an athlete on a low carbohydrate diet, we simply increase their rates of fat oxidation or reduce their rates of carbohydrate oxidation, but at the same time, also reducing their muscle glycogen levels, then hang on, why isn't their high intensity exercise performance impaired? Why isn't their more longer duration exercise performance impaired? Maybe there's something wrong with these
17:51
mechanisms that we postulate with these different models that we use to um ultimately base recommendations on. Yeah, it's super interesting, isn't it? Because of course, as you talk about your um higher intensity work and the research that we've discussed before on the podcast, almost adjacent to your work, or a little bit beforehand, there was of course, Louise Burke and her research that
18:20
did a similar study, they found there was performance detriments. I was listening to a podcast this morning, actually, and apparently it was like 2 % detrimental, whatever, in their performance. But it was still performance detriment being on a ketogenic diet versus being on a high carb approach. But their adaptation was just three weeks. And I'm sitting here listening to this. so therefore, what people are doing is they're like, well, know, Birkett, how they're very...
18:49
uh well renowned in sports nutrition research. They are like gold standard researchers in this field. They've been doing it for decades. If anyone's going to know, they're going to know. For whatever reason, that's been sort of put on a pedestal of ketogenic diastolic work. And in my mind, I'm like, only Louise and colleagues actually adapted her athletes for like six weeks. I'm under what they would have felt if that adaptation period wasn't a bit longer, because I believe that that's what...
19:19
that you and your team did, you sort of adapted them for a bit longer and looking at the application piece. Yeah. I mean, our studies have never been shorter than four weeks. So we make sure that in all of the studies, the adaptation period is usually between four and six weeks. Obviously, we wish in some cases it can be longer, but it's always been between four and six weeks. And none of those studies have performance ever been
19:47
uh negatively impacted when the adaptation period has been four and six weeks. I'm actually working with some others on a systematic review and mid-analysis just looking at this adaptation time period. So there's still lot of work to be done with that, but we're just looking at, here's all the low carbohydrate or ketogenic studies that measure performance or some marker of performance at the same time.
20:17
And now let's group them according to the duration, right, of that adaptation period. A lot of the older, more historical studies was just like a couple of days. Right? So you have ones that are just a couple of days, a week, two weeks, three weeks, four weeks, all the way to eight weeks, 12 weeks in some cases. And so what is, when, when, if you now put all these studies together, when do you get much more of a clearer sense of when exactly is performance much more likely to be m
20:45
impaired? When is performance more likely to be maintained? Or maybe is there any indication of where performance seems to be more uh enhanced as well? So even though it's more early days, kind of trying to do that work, it's still pretty clear that you're much more likely to find impairments in performance for the studies that are less than four weeks in duration. Yeah, which I mean, from a transition point of view, it makes perfect sense.
21:13
And I would just add there one thing because one of our previous studies um actually also uh looked at that because um we measured uh blood glucose by CGM and also uh blood ketones um as well. And we found that uh blood glucose kind of uh was stabilized.
21:38
at about the four week mark and so was blood ketones was also peaked at about the four week mark as well. Again, evidence for metabolic homeostasis and then obviously performance uh as well. So yes, absolutely from a metabolic standpoint or obviously from a just purely performance standpoint, at least four weeks or more seems to be the minimum. Yeah, nice one. And then of course you mentioned the glycogen depletion model of exercise performance. Now, m
22:07
I, and you'll need to school me on this, Philip, but I remember knowing that bonking wasn't related to glycogen depletion. I think we've known that for about 10 years, haven't we? That, you know, they've done studies looking at cyclists and they're testing this theory that you bonk when your glycogen is depleted. That's what we always thought we knew. And then I remember, I'm sure I remember studies that have actually tested that there and they're like, no, actually,
22:35
There's something else going on. It's not the glycogen that's the issue because glycogen is not depleted. So is that where that central fatigue model comes from? Yeah. Well, so yeah, we can go a little bit further back. So it was really in the 1960s. So this group of Scandinavian researchers, they developed this needle biopsy technique. And so really for the first time in history, they were able to biopsy
23:04
glycogen that's in the muscle or liver. So that's really a landmark paper um that spurred much of this conversation that was published in the late 1960s by Bergstrom uh and colleagues. And basically what they did, right, they did these biopsies in these athletes looking at muscle glycogen. And then what they would find is for these athletes, their muscle glycogen pre-exercise, so the pre-exercise muscle glycogen levels.
23:34
right before they started to exercise was elevated. And then these guys would then exercise for a prolonged period of time. And at the point of fatigue or exhaustion, right, they would measure their muscle glycogen levels again, and, you know, it would be, well, very low. And so therefore that idea uh started that, well, muscle glycogen depletion, right, seems to coincide with fatigue or muscle glycogen is an important factor when it comes to endurance exercise performance, because the next thing they did is, well,
24:03
hang on, how can we then manipulate uh these athletes muscle glycogen? Let's put them on different diets. Let's put, so that's what they did for just a couple of days. They would put athletes on a high carb diet, a moderate carb diet and a low carb diet. And then we'd have these guys again exercise at some moderate intensity until exhaustion. And they look at, you know, pre-exercise muscle glycogen. So as you can imagine, if you're consuming more of a high carbohydrate diet, then your
24:32
you're stuffing more uh glucose as glycogen in your muscle and liver. So pre-exercise muscle glycogen was obviously a lot more on a high carb diet, little bit less on the moderate carb diet and far less on the low carb diet. And then they want to see, well, how does, now that we manipulated the pre-exercise muscle glycogen concentrations, now let's see how that impacts endurance exercise performance. And what they found was that when they're on the high carb diet, higher pre-exercise muscle glycogen,
25:00
And that seemed to help that seemed to extend endurance exercise performance compared to obviously on the low carb diet, lower pre exercise muscle glycogen concentrations and fatigue, right? Fatigue set in sooner, right? Because now you started off with lower levels. And now it's not going to take me that long to, to burn through. Yeah, exactly. And now reach that point, right? Because that was the whole idea is that once your muscle glycogen gets to too low uh levels, then uh
25:28
fatigue sets in, right? Your RPE goes up or your affect uh goes down or like you were describing like bonking or hitting the wall, uh etc. But what, so that's kind of the history of where that originated. And actually, so even a couple years then after that, because that was 1960s and then 1970s, I know there was another pivotal study by, I think it was Salton and colleagues where they would then um
25:57
a carb load uh athlete, so three days before, in an effort to significantly ramp up, right, pre-exercise muscle glycogen concentrations, and they would have these guys, I think that was a 30 kilometer time trial. And their performance was significantly improved in this 30 kilometer time trial. So that's, it's all those, you know, early, early studies that seem to indicate that, hang on, you know, the
26:24
the muscle glycogen seems to be an essential or an obligatory fuel and or the pre-exercise muscle glycogen concentration seems to be very important. But the determining factor there that seems to influence that is the diet. So we got to make sure we're consuming or telling athletes to be consuming a lot of carbohydrates before an event in order to maximize that pre-exercise muscle glycogen concentrations. And then obviously during exercise,
26:53
we're going to be recommending athletes consuming a lot of carbohydrate during exercise in order to then the idea is a little bit different, right? Because you want to spare, quote unquote, spare this essential fuel. So all the recommendations, whether it's before, during, or after consuming a lot of carbohydrate before, during, and after is geared towards essentially glycogen. How high can I get it before exercise? Can I spare it during exercise? Or can I replenish it after exercise?
27:22
And so if you read the big review paper, uh you'll get that historical sense, but you'll also understand that um if you actually go back in the 1930s, there was another group of Scandinavian researchers also doing some different work, uh actually finding that uh exercise-induced hypoglycemia seems to be the exercise
27:52
stopper. So that was like in 1936 or 39. There was an old study by Bouillet and colleagues, another one by Christensen and Hansen. And a of these times these guys were just basically their own subjects. did a lot of the experiments on themselves, but they would just cycle or exercise for a long time and at the point of exhaustion and ingest a large bolus of carbohydrate. And then that seems to
28:19
uh restore exercise performance. it's interesting how that happened in already in the 1930s. And they even said in one paper, I even wrote this down, said, fatigue is a hypoglycemic symptom of cerebral origin. So that was in the 1930s. Fatigue is a hypoglycemic symptom of cerebral origin. And then a couple of years later,
28:50
Right. Then that seems to change dramatically with the, with the muscle biopsy technique and then all the focus shifted to glycogen and obviously industry, industry stepped in and, um, and we know what happened really there afterwards with a lot of the recommendations and the exercise science and sports nutrition field. But, but yeah, so now we come back to that topic, basically a hundred years later, evaluating oh
29:19
all the scientific literature over the last 100 years to see, well, hang on, is it more about fueling what we term your large glucose pool or the small glucose pool? Which one is more important? Yeah, because I have uh a few, like when I'm listening to you talk about that and it's almost like the muscle glycogen, it's like they sort of...
29:42
missed the wood for the tree, so to speak. So they were looking just at muscle glycogen, but did they look at liver glycogen? Did they look at blood glucose? Were they able to make those distinctions with those earlier studies? Yeah, most of those studies are not looking at liver glycogen. I that's much more difficult to assess from an exercise uh perspective. But what is interesting is a lot of those studies actually did measure
30:10
blood glucose. It's just that it seems they weren't very much interested in interpreting the blood glucose value. So even that old study, again, that foundational one by Bergstrom and colleague that was so pivotal where they put athletes on these different diets, low, moderate, and high, and they're checking muscle glycogen before exercise and then at exhaustion. So yes, they measured muscle glycogen, but what most people are not
30:40
familiar with is they also measured blood glucose. so, hang on, so at that point of exhaustion or the point of fatigue, yes, mean, muscle glycogen is low, but I wasn't the only thing that was low. Blood glucose was very low. It was definitely exercise-induced hypoglycemia. Now, this is the interesting part for that study. If you're saying that if the theory is that it's, well, it's all just
31:09
muscle glycogen and then you go look at that study by Berkshire and colleagues, at the point of exhaustion, there is variability. There is variability uh in glycogen at exhaustion. I mean, meaning at the point of exhaustion, sure glycogen is low but it's not to the same extent. Like it was a little bit higher on the high carb diet compared to the moderate or the low carb diet.
31:37
So hang on, so if muscle glycogen is really causing fatigue, then why at the point of exhaustion do you find great variability? It's not unanimous. Now in that same study, yeah, exactly, in that same study, you go, what is more consistent? And that is blood glucose. I blood glucose in that study uh for the moderate, low, and high carbohydrate diet, if I remember correctly, it was in the...
32:06
50s and 60s, milligram per deciliter. mean, clinical hypoglycemia is 70 or below 70. Those guys were 50s and 60s. So that should have been the main finding of oh that study is, look, blood glucose level is at very low levels, right? That's exercise-induced hypoglycemia. That seemed to be the common denominator, not so much muscle glycogen depletion.
32:35
interested to know if anyone has any idea as to why that was not reported. there any, they just, maybe, I guess they had this new technique, the biopsies, the technique. Yeah. Right. I mean, I think that happens a lot of times, right, when you have new technology and new techniques and that that kind of takes center stage and then your other variables, the more traditional variables kind of takes the backseat, so to speak. I think that's
33:05
more than likely probably what happened and just resulted in this kind hyper-focused view and attitude towards glycogen. It's interesting. was listening to, I think it was Andrew talking on another podcast as well about the history of sports nutrition and how we fueled athletes prior to this explosion of sort of like carbohydrate. And first of all, just to be clear, like I don't think that like
33:34
I I use carbohydrate when I train, know, I recommend my athletes do as well. I'm not up at 120 grams an hour or anything. I'm definitely more of a lower carb style approach, you know, maybe 30, 40 grams an hour. But even like back in the day, they used to fuel Olympians on protein, I understand. Yeah. So if you go read the paper,
34:03
kind of more towards the beginning as we're kind of more describing or detailing the historical aspects of it. Absolutely. So if you go look at the Olympics over the last 100 years or so, a lot of the focus was on protein-rich foods. that's how animal-based foods, protein-rich foods, and that seemed to be the standard for a long time up until really kind of the 1996
34:33
you know, Atlanta um Olympics here in the US, that's kind of when you started to see more of a shift to more carbohydrate based foods being more highly recommended. yes, there's, you do see that. Absolutely. Philip, can we, can we talk then about that exercise induced hypoglycemia before we crack on into muscle glycogen, liver glycogen, but
34:59
You mentioned the study in the 1930s. You mentioned the sort of missed data in the 1960s. What other research supports the idea of this exercise-induced hypoglycemia? Is there a lot out there in the studies that you reviewed? Yeah. mean, if you... Our review article includes data from over 160 performance-based studies.
35:27
And when we reviewed them all, put them all together, uh we found that close to 90%. So close to 90 % um of those studies showed that when carbohydrate improved performance, when carbohydrate was ergogenic and improved performance, that's because uh blood glucose was significantly dropping in the placebo group. when you notice, meaning if you have a
35:57
two conditions, right? There's a placebo group or a control group versus the other group is some form of carbohydrate supplementation. Whether it's 10 or 60 or 90, whatever many grams per hour is given, the carbohydrate is improving performance by helping to stabilize blood glucose concentrations because typically what you see and then the control group or the placebo group
36:23
is when you're much more likely to find uh exercise-induced hypoglycemia sublucos starting to decrease to low or very low levels. So that's what it seems. If you go look at all these performance studies, 90 % of them are clearly showing or seeming to uh indicate that that is the mechanism through which carbohydrate supplementation is ultimately uh improving performance by helping to prevent exercise um
36:52
induced hypoglycemia. And this goes back to the whole idea behind the small and the large glucose pool, right? So um the large glucose pool is just referring to your muscle glycogen, right? So all that glucose that's as glycogen within the muscle. I mean, you can, you know, that's about for typical person about 500 grams or so. The small glucose pool, that's the glucose that's now being stored within the liver as glycogen.
37:21
oh or just within the amount of glucose that's within the circulation. So what we're saying, and by valuing all of those performance-based studies, it's the carbohydrate ingestion is not so much impacting the large glucose pool, but it's impacting the small glucose pool because it's the small glucose pool that is ultimately kind of the key factor there in the sense of blood glucose regulation. So it's not so much
37:50
So it's not so much if my muscle glycogen levels are going down during exercise. It's more if my blood glucose levels are decreasing during exercise. That is what then triggers central or cerebral mechanisms resulting in those fatiguing symptoms, not so much glycogen depletion. And that obviously, as I'm sure we'll talk about later, if you're going like, what's the so what of that? Well, there's significant implications if you think...
38:20
the large glucose pool of muscle glycogen and somehow regulating exercise performance or resulting in fatigue versus you're going, well, hang on, maybe it's rather the small glucose pool. Totally, that interpretation will result in completely different uh practical applications and recommendations to athletes. Well, I mean, let's go there now because you, I mean, we've talked about this probably on the last couple of podcasts as well, is this shift to these higher
38:49
carbohydrate intakes of, know, research is looking at 90 to 120 grams of carbs an hour. People in practice are doing 150 grams of carbs an hour. David Roche on the, um he's like a, you know, he's won, I'm going to say, uh Leadville, I think a couple of times. Did he win? I think he record, he had a record at Western States maybe. And apologies if I'm getting the races wrong. They all sort of went into one, but I should know better.
39:18
But on 150 grams an hour, he attributes his success to these super high carbohydrate amounts. But in addition to that, though, if I'm listening to you, Philip, which I do, and Andrew, and of course, my friend and your friend too, Dan Plews, he looks at the research and he's like, well, the higher your carbohydrate goes, the more you're actually breaking down muscle.
39:43
glycogen, you're getting an accelerated breakdown potential muscle glycogen. Where is all that carbohydrate going even? Because we don't even think you're oxidizing at all. how does the research actually, how does that stick up to what we're seeing out there in practice now? Because it's absolutely in contrast. Yeah, again, if your belief is that muscle glycogen is
40:13
obligatory to exercise performance, um then the practice is about, again, as I said earlier, maximizing the large glucose pool before exercise and then during exercise, as you were just discussing, these very large uh intakes of carbohydrates during exercise, right? Because then the idea is, well, I'm using, rather, instead of using the large glucose pool, instead of using
40:43
energy that's being tucked away as glucose within the muscle, I'm using um what I'm ingesting, the gels, power, gatorade, whatever, that's exogenous carbohydrate uh oxidation. I'm oxidizing the carbohydrates that I'm ingesting orally for fuel and therefore the hope is that I'm tapping in less, I'm sparing the
41:09
essential fuel because I don't want that to run out. I don't want that to become depleted because then I'm going to experiencing those fatiguing symptoms. again, it's a lot to have to do with just the way you interpret it. Is it the large glucose pool? Is it actually the small glucose pool? But yes, exactly as you were saying um just now, but those large
41:33
It's interesting, there's evidence there studies out there that shows it's actually paradoxical. There are studies out there that show, especially at these very high intakes, at these very high intakes, 120 grams or more, that that actually accelerates muscle glycogen usage. Because the idea there is, or the way that that would work if your carbohydrate ingestion is so high,
42:00
Obviously, now your blood glucose goes up, your blood insulin goes up, that suppresses, significantly suppresses fat oxidation. And so the emphasis obviously on carbohydrate oxidation, lot of glycogenolysis is taking place. And so you're using up um paradoxically the so-called essential fuel that's in the muscle. yeah, so that should be considered. And obviously the other thing that you mentioned is
42:28
And we've published in this as well. I if you're consuming such large amounts, 120 or whatever it is, it's not like you're oxidizing that. It's probably only about 50 % of that large amount that you're ingesting is actually getting oxidized for fuel. So some of the unused amounts, right, is getting either stored or remaining in your circulation or for a lot of athletes remains in their gut causing those gastrointestinal.
42:55
symptoms which obviously is big issue for lot of athletes especially when they start to ramp up their uh carbohydrate intakes to such very high amounts. Now the other thing I was going to mention is even one of our previous studies because you were asking also earlier about just other studies. Look at this distinction between large and the small glucose pool.
43:25
And so, and again, that's, think it's a great example for this kind of distinguishing factor of, it rather the small glucose pool? Is it EIH? Is it exercise-induced hypoglycemia? Is the more likely contributor of fatigue? Or again, is it the large glucose pool? Should I rather be focused on stuffing my muscle with as much carbohydrate as possible?
43:53
And I think we did discuss this also in the last podcast, especially, I think it's important for these conversations. Because what we did in that study, again, we habituated athletes to high and low carb diets, and that was six weeks. And then we looked at their endurance exercise performance. So if you're, in that study, athletes were either consuming, know, hundreds of grams, I think it was like 400 or 500 grams of carbohydrates per day, or about 40 grams per day.
44:22
So that's all impacting the large glucose pool. And then we made them do endurance exercise for a couple of hours. No significant difference in their endurance exercise performance, even though for when they were consuming the low carb diet, Their large glucose pool would have been obviously much lower compared to on the high carbohydrate diet. So again, how could it be? So just another...
44:52
clear example there, how could it be about the large glucose pool if you can clearly manipulate that and yet you don't see any meaningful impacts on physical performance. So we did that but then we also looked, okay, well now let's see the small glucose pool. So they would do endurance exercise either on a placebo, right, so it's just basically flavored water or minimal carbohydrates supplementation and that study we gave them 10 grams per hour.
45:19
The reason why we gave them 10 grams per hour is because, well, I spent a lot of time in the lab trying to pilot what carbohydrate dosage can be ingested during exercise to help maintain blood glucose level, but at the same time, not significantly impacting substrate metabolism because there are metabolic consequences clearly of ingesting large amounts of carbohydrate during exercise.
45:47
Obviously, as soon as the carbohydrate intake starts to go up, um then fat oxidation goes down and carbohydrate oxidation goes up. So in that study, what is just the minimal amount of carbohydrate we can give these athletes during exercise with the idea of helping to maintain or stabilize blood glucose levels but without significantly impacting substrate metabolism, right, carbon fat oxidation rates.
46:16
during exercise. So that was the whole idea behind that. Plus the fact that you only have about four to five grams of glucose, right, in five liters of blood, right? That's normal. That's how much sugar you have in your... Exactly. And so that impacted the small glucose pool. And that extended, that improved uh exercise performance on average by about 20%, because if you look at that data, when they were...
46:45
on the placebo, our blood glucose was going down. Because the other thing that we did is we asked these athletes to come in and they fasted stay. Meaning they were more prone to EIH, they were more prone to hypoglycemia, they would do a 15-hour fast before they come in because that's been shown to deplete liver glycogen, not muscle glycogen. So they're already coming in, you know, obviously being more sensitive to experiencing EIH.
47:15
And now they're either just they're taking water or nothing or 10 grams of carbohydrate uh per hour. And I think average blood glucose when they were on the placebo was like 70 milligrams per deciliter. I that's the cutoff for for EIH compared to blood glucose, average blood glucose uh for when they're consuming 10 grams of carbs per hour was like 90 or 95 milligrams per deciliter. So
47:45
A lot higher. And that stabilized blood glucose and extended uh exercise performance. So even just a simple study like that was specifically designed to look at mechanism. Is it all about the large glucose pool? Is it muscle glycogen, muscle glycogen depletion, or is it rather uh reductions in blood glucose or EIH that's the predominant factor, especially during endurance exercise? How much glucose do we store in our liver?
48:15
About 100. About 100. So because it is interesting, isn't it? So a couple of things, like I know of a few athletes who've done the sort of metabolic cart testing once they've been adapted to a lower carb approach. And what they've found is that their fat oxidation isn't that suppressed when they take on board carbohydrate after that adaptation period. Like initially, when they're adapting, if they put
48:45
glucose into the system. They do suppress their fat oxidation the way that you talk about Philip. But in practice, what I've seen and what I don't know if you know Marco Altini, he has some excellent blogs on his low carb approach. I've interviewed him a couple of times. He uses a uh periodized carbohydrate approach where he goes very low carbohydrate and then puts it in around exercise. And he's managed to ramp up his fat oxidation levels by
49:13
like he's doubled his fat oxidation levels and improved a lot of his health markers and his body composition. ah But he did a test and he wrote it up in this beautiful blog about how he put in quite a bit of carbohydrate ah during his, or pre-exercise and during exercise, but in his fat adapted state, he was still able to oxidize fat. there's something about that.
49:40
um metabolic machinery that if you can get it working, then you don't necessarily have to avoid this other fuel source. And I do wonder whether that's like a good approach for a lot of people actually. I'm just curious as to your thoughts. Well, we have published on the fact that when athletes transition to a low carbohydrate diet, they're actually more metabolically flexible because some have argued that that particular dietary approach
50:10
will impair metabolic flexibility, but we have actually shown the opposite. I remember in one of the first studies we did, we had, now this is not carbohydrates ingestion during exercise, but beforehand, because we had athletes do a five kilometer run as fast as they can. And then when they were on the high carbohydrate diet, I think it was like 94, 94 % of their total energy expenditure came from carbohydrates.
50:37
So such a small amount, because the remainder is like only like 6 % came from fat. I mean, that's the kind of stuff where these beliefs come from that, know, carbohydrate, that's glucose is the preferred fuel source, especially during more higher intensity exercise. In any case, then we took those exact same athletes, adapted them to a low carb diet that was six weeks. And then I did the, you know, run a 5K as fast as possible.
51:03
In that case, % of the energy came from carbohydrate, 35, close to 40 % of the energy came from fat. That's obviously indicative of greater metabolic flexibility. They're able to use now a lot more fat for fuel at a very high, because that was at 82 % VO2 max. So yes, and we've shown this in other studies as well, so that's just a good example.
51:32
We are currently doing an interesting study where um we're looking at this uh mythical, if you want to call it that, of dose response with carbohydrate ingestion. And so we're having cyclists perform endurance-based exercise um and there's really four conditions and it's either a placebo
52:01
uh or it's minimal carbohydrate supplementation uh at a rate of 10 grams of carbohydrates per hour, uh or it's 60 grams of carbohydrates per hour, or 90 grams of carbohydrates per hour. So we're about halfway because we're uh with multi-site design. And so we have uh our collaborators at Ohio State. They're basically doing part of the study. We're doing another part of the study.
52:30
And we're about halfway through, so I can't share too much, but the results are definitely interesting, especially as it pertains to kind of what you were saying and how carbohydrate ingestion, the metabolic effects that that has. Now, in this particular study, all these athletes are habitually consuming a high carb diet. Okay, so they're all habitually consuming a high carbohydrate diet. That's the metabolic state.
52:54
that they are coming into the lab. And then it's, okay, now let's see how you do on zero, 10, 60, 90. What happens not just to performance, right? Is their endurance exercise performance better? Is more actually better? But then also the metabolic effects. so just, I mean, I can't say obviously too much, but just from a metabolic standpoint, absolutely. Like on the zero and 10 grams of carbohydrates per hour,
53:25
As you would suspect, if you understand the physiology, there is a lot more fat oxidation taking place. And then when you start to ramp up the carbohydrate ingestion, Fat oxidation is going down and now more energy is coming from carbohydrate ingestion. Now the question which you're alluding to um is what would happen to athletes who are consuming a low carb diet?
53:52
and then doing a, whether it's 10 or 60 or 90 or whatever amount of carbohydrate during exercise, do those performance, are their performance somehow different than individuals who are basically consuming a high carb diet and what also are the metabolic effects? And so don't, so that's, you know, speculation at this point, because we're almost done with the one study, but again, the follow-up study would then be to look at
54:20
Okay, now let's adapt these guys to a low carb diet and now let's provide carbohydrate supplementation during exercise and are the metabolic and performance effects the same? So you're going to have to unfortunately stay tuned for that. yeah, I wish I could tell you from the current study, right? Because also if you read the review paper, we also discussed this carbohydrate
54:47
uh dose escalation and how that impacts or maybe doesn't impact exercise performance. actually not a lot of well-designed studies on that, especially ones that are not uh funded by industry. And so, the goal of our current ongoing study was just to design one of these carbohydrate dosing studies and see what exactly is happening to performance and also metabolism if you go from...
55:15
scale it all the way up. You go from low to moderate to those high doses. Yeah, that'll be super interesting because I do think there is, I have a few thoughts around it. Someone like Marco, is a very good, it's just a case study, it's an N equals one. He's a very good athlete, but he massively improved when he shifted his metabolic state to be one that was able to burn more fat. He was able to reduce down his...
55:43
his carbohydrate, all the things you would expect for like, this is not news to you. And he was able to race on a lower dose of carbohydrate. He still had, I think it was 40 or 50 grams and he felt amazing. And then he just wanted, because he's got access to all these tools, he's like, I wonder what happens if I do go in and have a high carb approach during my exercise, what happens to my fat oxidation? Nothing. He was great. But then it was also interesting because he then flipped it up and he's like, I'm going to have...
56:12
long would it take me to lose my benefits of fat oxidation?" He's Italian. He went back on his high carb diet for several weeks and he figured out that he could pretty quickly reverse his ability to burn fat. But because he had built that machinery, didn't actually take long for him to be able to um go back to how he was after a period of low carb, which I just think...
56:39
even though it is N equals one and you guys are doing a great job at looking at this in the lab as well, this is just continuing to uh inform our understanding of using different fuel types and of time and place for, maybe there is a time and place where your carbohydrate is a little bit higher depending on the type of activity you are. For age group athletes like us, I'm not talking about elite, which I do want to actually discuss in a minute, but there is...
57:09
I think there's potentially a time and a place for that, just as much as there's a time and a place to be able to, or to adapt yourself to a lower carb intake and really sort of build that metabolic machinery again for athletes. Yeah, yeah. mean, all I can say is, at least from our work, habitual diet doesn't seem to significantly impact
57:38
uh exercise performance and that's studying exercise performance across a variety of different events. know, shorter duration, higher intensity, middle distance and your longer duration endurance events. So because that's what we're saying there, right, is if the habitual diet is not impacting having a meaningful impact on on exercise performance, that's
58:05
that all goes back to the large glucose pool. And then the fact that you can manipulate that, right, by consuming a low or medium or high carbohydrate diet. And yes, that's gonna definitely impact the large glucose pool, your muscle glycogen, but it doesn't seem to have meaningful implications to exercise performance. Now I say that, um but also for anybody listening to that,
58:31
Remember, in these all these different studies that we're doing, you're ultimately looking at averages. And uh if you group all the data together and then compare, well, here's the uh average on the low carb and the high carbohydrate diet. So behind those averages are people and people respond uh differently. And so actually in every single one of those studies, doesn't matter what the performance outcome were.
58:58
Some are doing better on the low-carb approach and some are doing better on the high carbohydrate approach. But it's still important to just kind of back up there and go, well, sure, in all these studies, not just that we have done, but also others, it's still important to understand what I was just saying there. Yes, I can manipulate the large glucose pool by consuming obviously different types of diets, but that doesn't seem to inherently be such an important factor, not as at least as it once thought was, or thought to be.
59:27
to impacting performance. it seems to be more about manipulating the small glucose pool. Yeah, for sure. And I guess I just get excited thinking about the idea that shifting between different dietary approaches is maybe somewhat helpful from a metabolic health perspective. The same reason you're interested in it from the other health perspective.
59:55
like athletes don't have to be high carb all of the time to experience any performance benefits at all. Which actually, if I'm thinking about athletes, those who are geared more towards those higher intakes are elite athletes. I suppose this is probably why you're getting all of the push backs because people like the Tour de France riders, have 120 grams an hour. You've got the...
01:00:24
really successful ultra endurance runners who are still having 80 grams of carbs an hour. Does your research, is that in opposition to what we're seeing in terms of performance? Are you saying, hey, Kelly and Jaune is going to be great on 20 grams of carbs an hour? I think this is what people are hearing, I think. Yeah. I guess that's the question.
01:00:53
For those individuals um who are advocating or recommending or just saying from personal experience, this is one of the reasons um why my performance is so good. Well, is it because of, know, is it so it's all because of the high carbohydrate ingestion during exercise? Well, how do you know, how do you not know that you would also not do something similar by
01:01:23
you know, consuming 60 grams or 40 grams or 30 grams or 20. Yeah. Like how do you get, was that actually tested? I mean, when it comes to performance, I mean, there's so many different variables that ultimately is impacting, uh, you know, performance. So especially in that upper enchilon, I mean, those, those guys right there, mean, to what extent are, are obviously just genetic factors coming to play. Um, that, that's obviously a
01:01:50
a big one. So you're trying to then tease out, know, here's our, here's our your, your elite athletes. And clearly they, there's genetic advantages maybe for them. Then to what extent is them consuming 120 grams of carbohydrates per hour doing anything above and beyond that? I agree. That's a hard, you know, sell right there. So, um,
01:02:18
But because our argument is just that, as soon as you stabilize the small glucose pool, um there seems to be no additional performance benefits. And again, it doesn't take that much carbohydrate ingestion to stabilize your blood glucose level. Yeah, and actually, how does this shift in terms of recommendations? I guess that's the big question, the overarching question that um anyone listening to this will be like,
01:02:48
Well, what does this mean that I should be having four grams of carbohydrate an hour? Like, can we glean that from what we already might know? Like, what are your thoughts there? Yeah. So our review is saying that rather the emphasis of the focus should be on a small glucose pool. And like we already discussed, it doesn't take that much carbohydrates to help
01:03:15
stabilize or normalize your your small glucose pool and So the traditional approach right or the the old model right was all geared towards the large glucose pool Okay, then you're consuming a of carbohydrates before and also during exercise for obviously different purposes as previously discussed But if we're saying if we're saying exercise and use hyperglycemia if that's the primary
01:03:41
uh That's the primary factor in uh inducing fatigue, especially during endurance exercise. Then hang on, oh then all of a sudden, what I'm doing before doesn't become like that, that important as we previously discussed, low on high carbohydrate diet since that's impacting large glucose pool. But then it's more so, but what am I doing during the exercise to helping to maintain
01:04:08
a glycemia, right, normal blood glucose levels during exercise. I'm trying to prevent, right, significant reductions in blood glucose levels. And I can do that with relatively small amounts. Yeah. That's the whole point. I can do that with relatively small amounts as I was discussing previously in one of the studies we did, it was just 10 grams. I mean, 10 grams of carbohydrate per hour. In that study, it was
01:04:36
So we did about 3.4 grams every 20 minutes, because that's the interval in which we administrated the carbohydrate, which comes out to be about 10 grams per hour. So that's such a small amount. It was sufficient, clearly, to help maintain blood glucose levels during exercise, to prevent exercise-induced hypoglycemia, and extend uh exercise performance. Yeah. And that's not overly different from the carb rinsing studies that they did back in the, I want to say,
01:05:06
like the early 2000s, I can't remember when there was a sort of spate of them with, yeah, cyclists would put sports drink in their mouth, rinse it around and then sort of spit it out. Had a similar effect. Was that preventing potentially that exercise-induced hypochondriacemia as well? Yeah, I think that's different because there's no real ingestion of the carbohydrate, but it's still kind of, both are still working through the centrally mediated uh mechanisms, right? Because what we're saying with
01:05:34
with this with EIH, right? So once your blood glucose level starts to drop significantly during exercise, and it doesn't have to be just at the clinical level, right? Because clinical hypoglycemia is around 70 milligrams per deciliter, right? So once you get to that point, or obviously lower, now it's clinical hypoglycemia. If you go read the paper, right, it's also just about that relative drop from baseline. Yeah, so what is that relative? I started off at
01:06:03
at 100 or hopefully not above 100 because then you're pre-diabetic. But whatever you had that baseline was and then you drop below that 20, 25, 30 units. So even just seeing that large relative reduction in blood glucose, that's enough to trigger those cerebral or central systems.
01:06:29
Your brain recognizes that your blood glucose level is obviously going down. And that's where the whole central governor theory comes into play. you're experiencing more of those fatiguing symptoms. You have less motor unit recruitment and activation. So ultimately, obviously, once that happens, you're going to want to slow down or ultimately stop as a result. Yeah. So if someone's listening to this, they're like small glucose, just to finish up, small glucose pools.
01:06:59
So if I make sure that my liver glycogen is topped up and say they're exercising in the morning about to do something sort of higher and not even thinking about what their habitual diet might be, but if their liver glycogen is topped up, then they've got enough on board. And that's like, if your liver carries say a hundred grams of glycogen, did you say we reduce by 50 % our liver glycogen overnight or something today?
01:07:25
Well, yeah, I mean, if you're going to do an overnight fast, I know there's previous studies that have shown like a 15-hour fast is going to significantly reduce your liver glycogen. Yes, yes. So if you have anything in the morning, it's really just to top up your liver glycogen before you go out for a higher intensity, for whatever exercise session you're doing, that is likely, but you don't have to put in like...
01:07:52
100, 150 grams of carbohydrate before you head on out the door type thing. Not that anyone really does it anyway, although Sports Nutrition Guide, Sports Nutrition Guidelines would have you have wonderful grams per kg body weight, very seldom do we do that. Chuck a banana in and go out the door. Yeah. mean, so we're, I mean, just to make it very simple and practical, um just think about how can I help
01:08:19
how can I maintain my blood glucose levels during exercise? I don't want to see a significant uh drop, right? And this is obviously now much more likely to happen for exercise that's longer than an hour in nature, any of those uh endurance-based activities. Then you go, well, I'm going to consume carbohydrate during exercise. And obviously that is helping to maintain the small glucose pool, right? Your blood glucose levels. But I don't have to do...
01:08:47
60 or 90 or 120 or even more. I can get away with much smaller amounts, right? Because remember then that conversation, which is quite significant and obviously results in a big paradigm shift the way we think about sports nutrition in general, but that conversation is also important from just an overall metabolic health standpoint. these um topics and conversations is not just purely performance driven, which
01:09:17
we have been discussing over the last hour or so, but it's also very much centered towards metabolic health since it's not just, you know, general population who have seen significant deteriorations in overall metabolic health, right, chronic disease, et cetera, but we've also seen a larger uptick in, you know, metabolic ailments and... uh
01:09:41
uh you know, different conditions and diseases also in athletes in your athletic populations as well. And we've published on this and I think in one of the podcasts, right, we talked about that. ah Where in one study we found, you know, 30 % incidence of pre-diabetes. Again, that's in athletes. And we're not the only ones to have found that. So yes, the other thing is what I have personally
01:10:10
seen in the lab. So over last 10 plus years, because all of these studies are on usually endurance-based athletes. So runners, most of these guys are doing marathons or ultra-marathons on a regular basis. Triathletes, I mean, these are individuals who are obviously clearly doing a lot of activity on a regular basis. So over the years, as these guys are coming into the lab, for most of these studies, we're measuring blood glucose.
01:10:40
kind of almost one of the first measurements that we get is kind of just a baseline blood glucose. for, in addition to the fact that uh for most of these studies, they're coming in at some kind of facet state, right? It's like an overnight facet So you obviously ideally you would suspect because they're athletes, they're insulin sensitive, right? Blood glucose is below a hundred milligrams per deciliter, know, the eighties, nineties or something like that. I've seen a significant uptake of
01:11:10
of these athletes in their 30s and 40s, sometimes also in their 20s, who are coming in with blood glucose values above 100 milligrams per deciliter, meaning they are pre-diabetic. So yes, we've published on it, but just anecdotally, just spending a lot of time in the lap of the last 10 years, this has become, I think, a serious issue. Yeah. Yeah. So even in these highly active...
01:11:38
individuals were seeing metabolic uh abnormalities. so we have to stop and think, you know, how is it possible that these highly active individuals are seeing these metabolic disturbances? Does that have something to do with the amount of carbohydrate that they're ingesting before exercise, during exercise? Why have they been doing that? Because all the focus has been on the large glucose pool. But here we come out now with a complete paradigm shift and say, hang on,
01:12:08
If the focus is on a small glucose pool, then you don't necessarily have to consume all that large amounts of carbohydrates for training or before an event, carbohydrate loading and all that stuff. And you don't have to consume a very large amount of carbohydrates also during training or racing as well. So that completely changes the playing field. And I think we result in ultimately significant improvements for a lot of uh individuals who are physically active, recreationally active, et cetera.
01:12:34
I agree. I um think what I'm, I don't think what you're saying is everyone should go keto. Like, I think this is, that's what, no, at all. It's just eat an appropriate diet and you don't have to stuff your face full of carbohydrates for the, your average age group athlete will still, you know, doesn't, won't really need to have.
01:13:05
The average age group doesn't have to consume heroic amounts of carbohydrate. think that's what I'm hearing, which actually will save us quite a bit of money, won't it? So, I mean, there's another great thing that like, you know, you don't have to be like $200. Yeah, or even going from, if you are doing, you know, 400 or 500 grams, right, if you just reduce it from that amount.
01:13:32
to 200 or 150 or 100, that's already a significant improvement. Or again, if you were doing these very large amounts because you spent some time on social media and some other guy said, hey, I'm doing so great at 120 or whatever, and then you drop it down to 60 or 50 or even like we study, just 10. So even just simple recommendations like that. So yes, we're in.
01:14:01
you know, not saying you have to go completely now to the opposite to the other extreme and you have to do low carb, have to do ketogenic diets or complete, totally in uh a, or train or in a fasted state or anything like this. We're just kind of more geared towards, just think about it, more geared towards the, guess, if anything you get from this conversation is that you have to...
01:14:28
glucose pools in the body and they're regulated differently. And from a human health or performance standpoint, maybe the emphasis should rather be on the small glucose pool. Yeah, no, I love it, Phillip. I mean, I definitely have a bias towards a lower carb approach as well. And I think, you know, the more that we can sort of talk athletes off the cliff of that sort of 90 to 120 and like, hey, you know what, 60 is going to be fine for you.
01:14:55
the less GI issues people are going to have, they're still going to be able to recover, the more protected their metabolic health is in the long run, so they'll be able to do what they love doing for longer. Yeah. would just say, stay tuned for this other study I was talking about earlier. Because again, we need these proper carbohydrate dosing studies. We need to... That's obviously not industry funded.
01:15:23
the way we can clearly see is more moderate doses clearly superior to lower doses and are higher doses more superior to moderate doses. guess often that's what most people are gonna be interested in. If I scale it up, uh do I see that significant enhancement in performance? I care about that, but I also care a lot about just the metabolic uh effects as well.
01:15:50
But I understand obviously most people are just going to want to know, if I do more, does that necessarily equate or almost certainly to improvements in performance? And to what extent? What is the meaningfulness right off that improvement? Is it like a 1 %? Is it a 5 %? And I think people will be very, very surprised when they see these findings come out because it might not be as you might suspect. Because a lot of the guys even coming in,
01:16:20
mean, pretty much every single triathlete, because that study is on triathletes who comes in, that's already the belief. I agree. They're already doing obviously these very high amounts. Obviously, we're blinding them, right? They don't know what they're ingesting. And it's funny because sometimes it's like they think, oh, I just did 90 grams when they were like on a placebo. Yeah, interesting.
01:16:44
They're taking 60 grams when it's 10 grams. So that's how you have to do those studies. You have to completely blind them to all these different conditions and then just see how they perform. when we show these athletes the results, I can tell you right now they're confused and surprised at the same time. Philip, do you play poker at all? No, unfortunately not.
01:17:09
Yeah, no, I'm probably, that's probably not a bad thing because I'm not sure about your poker face. I think you probably told us about telling us what we mean, but hey, we will wait. We'll wait. We'll We will see. We will. Please, so obviously I will put a link to the paper where people can read it in the show notes. Where else might people find out more information about this and the sort of research that you guys are doing?
01:17:35
Yeah, I would definitely uh urge everybody to um go just read the paper. um Or again, it's kind of long, so maybe you put it into some AI system and just get a short brief gist of it. obviously, or you can just listen to this podcast and we kind of discussed the main findings uh from, again, it is really the most authoritative review.
01:18:06
on that topic. mean, there's no other paper that comes close uh to that. mean, like I said earlier, mean, just a massive amount of studies that were reviewed. And again, the key statistic was that almost 90 % of the studies, right, where carbohydrate improves performance shows falling blood glucose in the placebo group or in the control group. that's it right there. But yeah, you can def... So read the paper or... um
01:18:34
Yeah, you can go to ResearchGate, I guess, and find some of our other work or on social media. Again, I'm not that active, but yeah, I'm on X or especially, know, is very active, Tim Nokes on X and Andrew is also, Andrew Krutnik is very active on, yes, on X as well, where you can again find some great other information as well.
01:18:57
Amazing. Philip, as always, thank you so much for your time. I really enjoyed this conversation. I look forward to the next one where we dive into this new research. Cheers, Philip. Thank you.
01:19:21
Alrighty, hopefully you enjoyed that. It certainly is food for thought, right? And really interested to see these next studies come out from this group and also just engage in this conversation. What I will say is it's not like zero carbs is the answer. It's not like carbohydrate during sport isn't important, but it's just understanding the mechanism for how these work for performance. And I think that's a really interesting question for those science minded amongst us. questions, comments,
01:19:50
queries, anything of the above, hit me up. I'm on Instagram, threads and X @mikkiwilliden, Facebook @mikkiwillidenNutrition, or head to my website, mikkiwilliden.com. Scroll right down to the bottom, pop your name in the little box and jump on my weekly email where I share insights, research studies, thoughts and opinions that don't appear anywhere else in my weekly email. All right guys, you had the best week. See you later.