#208 – A low-carb diet may boost exercise performance and health | Dr. Tim Noakes & Josh Clemente
High-carbohydrate diets and carbohydrate loading have been long-standing tenets of athletic training and competition, but newer research indicates a low-carbohydrate diet may be more beneficial for performance and overall health. Dr. Tim Noakes and Josh Clemente discuss how a fat-adapted body can rely on fat as a fuel source at all exercise intensity levels, rather than burning mostly carbohydrates, and how such adaptation and dietary focus may reduce one’s risk of prediabetes and Type 2 diabetes.
- Dr. Tim Noakes on Twitter: https://twitter.com/proftimnoakes
- New Atkins for A New You: The Ultimate Diet for Shedding Weight and Feeling Great: https://www.amazon.com/New-Atkins-You-Ultimate-Shedding/dp/1439190275
4:28 — Dr. Tim Noakes explains his career trajectory
Dr. Tim Noakes explains his switch from thinking that high-carbohydrate diets were essential for athletes to thinking that low-carb diets are key.
I was totally committed that carbohydrates were essential for exercise. And I bought into the idea that muscle glycogen depletion causes fatigue during prolonged exercise. So I went along with this and wrote the book Lore of Running, and it’s all full of carbohydrates. You must eat every single carbohydrate you can see. You must eat and you must load up on carbohydrates. And the last time I wrote it was 2002. Now my career took a major change in 2010 because I learned about the low-carb diet, and I read Eric Westman and Jeff [Volek’s] book, and that convinced me in two hours that I was completely and utterly wrong. So I changed that day. And within four months, my health had improved dramatically. I’d lost a lot of weight. My running was improving, and I started telling people that, “Listen, I’ve gone to this low-carb diet. Here’s a guy who’s promoted the high-carb diet, and I’ve now gone to a low-carb diet. And I wrote some articles, and the first response was I lost all my funding.
19:04 — An adapted body can rely on fat for all exercise intensities
Our bodies run on two basic fuel types: carbohydrates and fats. And newer research shows that the body can adapt from a reliance on carbohydrates to a reliance on fat at all exercise intensities. Previously, researchers thought that above a certain threshold of exercise effort the body had to run on carbs. But research shows that’s not true.
The only reason you burn glucose is to regulate your blood glucose concentration. That’s why you burn glucose. What happens in the body is that the muscles respond, and if they’ve got lots of glucose, they will burn glucose. They have to, and the only way you can stop that is by not eating carbs. Then your muscles are full of fat and very little carbohydrate, and then you will burn fat. And something, which I didn’t really catch onto until two years ago, we studied an athlete who was a low-carb athlete, but he was a really good athlete and so that he could cycle at a very high rate from the moment he cycled and we had him do a 100K time trial, and from the incident he got on the bike, he was burning 1.7 grams of fat per minute. Which normally, as you know, if you’re carbohydrate adapted, you would never get anywhere near.
22:30 — The body will never get to a state of no glucose circulation
Dr. Noakes explains why the body will never burn just fat, even in a fat-adapted state. Glucose burn is necessary to a certain extent.
Glucose is obligatory for the brain. And that’s why I think blood glucose oxidation goes up during exercise. You can do what you like; you can’t stop it. You can start exercise carbohydrate depleted and the rate of blood glucose oxidation is the same. So it’s fulfilling some obligatory role, and obviously part of it is brain, some of it may be kidneys, some may be other tissues. And it may also be obligatory for muscle. I’m not going to exclude that. But it’s such a tiny amount that it’s not as we used to think—that it’s the predominant source. It’s a tiny, tiny amount, and I’m not excluding the possibility that you need a little bit of carbohydrate to keep muscles working properly.
23:28 — A delicate balance of macronutrients is likely necessary
While research is now indicating that a lower-carb diet (rather than a higher-carb one) may be beneficial for exercise performance and overall health, Josh Clemente points out that a no-carb strategy isn’t the answer. More research is needed to determine optimal macronutrient intake.
We don’t want to get over hedged in one direction or the other. And the fact is that we have been in one direction. As somebody who has tried to train in various ways over my lifetime and trying to sort of replicate what I see the elite athletes doing—assuming that’s what’s best—it really leads you to a very carbohydrate-heavy fueling strategy because that’s really what you see somebody in the gym or training for the Tour de France pipeline and the way that they’re consuming calories. The vast majority in those training cycles are carbohydrates. And so the whole culture is oriented around that. And it’s not that we should overcorrect in the other direction; it’s that, in fact, the science probably shows that we’ve adapted to operate in that environment, and we need to understand what the natural adaptation is.
29:11 — Before the high-carbohydrate craze, elite athletes were fat adapted
The concept that a high-carbohydrate diet was beneficial to endurance athletes took shape in the late 20th century. But before that, elite athletes were often burning fat for fuel.
Who were these athletes in 1986 who were burning so much fat? The answer was they were Olympic-class elite cyclists in Austin, Texas, from where Armstrong arrived. Lance Armstrong comes from there. So they’re obviously very competitive. Ed Coyle got some of the best cyclists, and they were fat adapted in 1986. Why? Because that was before the carbohydrate craze hit.
33:46 — Fat oxidation in muscle may have a protective effect against Type 2 diabetes
Dr. Noakes explains how, despite his high-mileage training as a runner, his exercise routine on a high-carbohydrate diet didn’t prevent him from developing Type 2 diabetes. However, research indicates that glucose control improves on a high-fat, low-carb diet.
Having developed Type 2 diabetes as a result of following this high-carbohydrate diet and running 70 marathons or ultramarathons and still getting Type 2 diabetes, I’m a bit more suspicious about the health effects of the diet. And the study that we did also showed that 30% of these recreational athletes became pre-diabetic when they ate the low-fat, high carbohydrate diet. When they ate the high-fat, low-carbohydrate diet, their control was absolutely perfect. And Andrew Koutnik, who was crucial in this analysis, showed that those athletes who burned the most fat were the ones whose glucose control improved the most when they went onto the high-fat diet. So that was the first time linking fat oxidation in muscle with more resistance to Type 2 diabetes or prediabetes.
36:39 — Exercise does not cancel out the risk for metabolic disease if diet isn’t accounted for
Exercise alone has many health benefits. But training on a high-carbohydrate diet can still put someone at risk for metabolic disease.
Now you go to these marathons and you see that people finish in six hours. They’re a metabolic disaster. They’re carrying all this extra fat, but they believe, because they’re running, they’re going to be healthy. And that’s not true. Not we, but others are telling them to eat a high-carbohydrate diet to run faster. So to get back to your point, I would say that the only people who can eat high-carbohydrate diets as runners are those who prove they’re not prediabetic or not going to become prediabetic. You have to earn your carbs by being healthy; if you’re not healthy—and it’s a simple—if you’ve got visceral obesity, if you’ve got a tummy and your waist is too wide, carbs are killing you. And the reason why I’m so vocal about this is I watched my dad die from Type 2 diabetes and I couldn’t help him because I didn’t understand. And it is an awful, awful death. And that’s in a sense why I came out and said I was so wrong about the diet, because I knew that a lot of people will become diabetic if they follow the dietary advice I was giving. And I had to say, “Listen, I’m terribly sorry I was wrong. I don’t want you to die. I don’t want you to be sick as a result of this.”
47:25 — The body can cope with fasting
Dr. Noakes notes that exercising in a fasted state may be beneficial, but we need more research.
Well, I just think fasting is really healthy, and combining it with exercise would suggest to me that you’ve got a double benefit. I don’t have any evidence that that’s the case, but I do know that fasting is one really good way to help reverse metabolic syndrome. So I think that stressing your body in those two ways is very helpful. You see, the irony is, the greatest threat to the body is not starvation or fasting; it’s high-carbohydrate diets. And people don’t understand that. By the way, by starvation, I mean a few days of not eating, but the thing the body can’t cope with is a high-carbohydrate diet. It can cope with fasting.
54:32 — The high-carb training trend has been perpetuated by the carbohydrate industry
Dr. Noakes explains how research funding from the carbohydrate industry has perpetuated the idea of the high-carb diet being beneficial for athletes. But he says he’s concerned about how that can be detrimental to health.
What’s burning on my mind is to get people to accept the data. And the only way we can do that is by having lots of people who previously promoted high-carb diets doing research and proving that they were wrong. That’s what we need to do. Probably that’s not going to happen, because the industry funds people to study carbohydrates. And that’s partly the reason why carbohydrates are so dominant. And I’m party to that because we were funded by the carbohydrate industry for 15, 20 years. And we did fabulous studies, which I now realize were really amazing, but they were all looking at carbohydrate metabolism. And only right at the end did we do some studies where we did low-carb studies and they were critical. They were absolutely critical because they showed where the controls were: if you had high muscle glycogen, you burn carbohydrates. If you have low-muscle glycogen, you burn fat. And even insulin isn’t the main driver. It’s what’s in the muscle at the start of exercise. Insulin helps and glucagon helps, but the driver is in the muscle itself. So I think that’s what I’d like to see, because I think runners are getting the wrong advice, and their health’s being affected—as my health was affected. And I just wish that I’d known about this high-fat diet when I was running when I was 20 or so, because my career would’ve been very different.
Prof. Tim Noakes (00:00:06):
I spend my life now telling people that the key to being healthy for metabolic health is you’ve got a titrate how much carbohydrates in your diet and how much you can cope with on the standard diet we’re eating too much carbohydrate and the body couldn’t regulate their blood glucose under those circumstances, and that’s going to harm them. They will become diabetic once they keep on that diet for 10 or 20 years, they will become diabetic. Now, do they represent all runners in the world? I would say they probably do that 30% of runners eating this high carbohydrate diet in their thirties or forties. If we tested them properly, we’d show that they’re pre-diabetic.
Ben Grynol (00:00:52):
I’m Ben Grynol, part of the early startup team here at Levels. We’re building tech that helps people to understand their metabolic health. And along the way we have conversations with thought leaders about research backed information so you can take your health into your own hands. This is A Whole New Level.
Changing your mind. What are the implications of changing your mind? Sometimes you can see around the corner and other times you face the unknown unknowns. Well, that was very much the case for Professor Tim Noakes back in 1981, professor Noakes started practicing sports medicine and as an avid runner, he had this theory about hypoglycemia and exertion. He had this idea that our glycogen levels get depleted if we’re under fueled with carbohydrates. He started researching, writing and promoting this concept. Well, fast forward to 2010. He read a book by Eric Westman, New Atkins for a New You, and it completely changed his perspective on fueling with carbohydrates and sports performance. What ended up happening is he lost his funding. He got kicked out of his university as professor, and he even had to go to court to settle the matter, which took until 2018 to resolve.
To take it from his Twitter bio, Professor Noakes is a South African scientist, an author, an emeritus professor runner, and he’s focused on the low-carbohydrate, high fat diet as it relates to performance. He’s no longer registered as a medical doctor, and in fact, he’s focused on spreading scientific information, not medical advice. Dr. Noakes founded the Noakes Foundation where you can find him thenoakesfoundation.org, and the goal is to fix the future outlook of human health by changing the way that people eat and the food policies that enable it. Dr. Noakes sat down with Josh Clemente, co-founder of Levels, and the two of them discussed this outlook, discussed how he changed his mind and changed his perspective and how he’s now focused on spreading this information around low carbohydrate diet as it relates to performance. There’s lots of research being done in the space and he continues to push the thought leadership board. Anyway, no need to wait. Here’s Josh.
Josh Clemente (00:03:18):
Professor Tim Noakes, thanks so much for joining us here on A Whole New Level. I’m really excited to dig into some of the concepts of metabolism, metabolic fitness, fitness specifically including our research collaboration on a lot of those things that we recently had published. So thank you again for joining us.
Prof. Tim Noakes (00:03:32):
My pleasure, Josh, lovely to be with you. Thank you.
Josh Clemente (00:03:36):
Awesome, well your career has spanned many decades and covers the whole spectrum of metabolic health as well as fitness and fitness adaptation under different metabolic circumstances. And I’m really excited to speak initially about your recent work, which Levels had an opportunity to be a part of which focused on adapting to low-carb, high fat diets for recreational male athletes. So I’d love to hear your summary of that recent work and then we kind of dig into how those findings apply to certain groups.
Prof. Tim Noakes (00:04:04):
Sure. So let’s go back to the history so people have got my involvement.
Josh Clemente (00:04:11):
Prof. Tim Noakes (00:04:12):
So I started doing sports science in 1981. That’s when I really became committed. And the first thing we studied was hypoglycemia during exercise because I was sure that hypoglycemia developed during exercise and at that time people were being encouraged even not to drink water during marathons. It was quite a long time ago and quite different. And so we started experimenting and our focus was on the Comrades Marathon, which is 90 kilometers. And it became very clear that some elite athletes developed hypoglycemia and really struggled. And then there were examples of where they took carbohydrates and were able to finish the race comfortably having slowed down and then they take the coves and then they do well. So together with Bruce Fordice, who was in fact probably the greatest Comrades runner in history, we developed a product called FRN.
[inaudible 00:05:07] was a marathon runner myself. And so that was the first goo that people used during exercise. And so I was totally committed that carbohydrates were essential for exercise, and I bought into the idea that muscle glycogen depletion causes fatigue during prolonged exercise. So I went along with this and wrote the book, Law of Running, and it’s all full of carbohydrates. You must eat every single carbohydrates you can see. You must eat and you must load up on carbohydrates. And the last time I wrote it was 2002.
Now, my career took a major change in 2010 because I learned about the low-carb and I read Eric Westman and Jeff Volek’s book, and that convinced me in two hours that I was completely and utterly wrong. So I changed that day and within four months my health had improved dramatically. I’d lost a lot of weight, my running was improving, and I started telling people that, listen, I’ve gone to this low-carb diet. Here’s a guy who’s promoted the high-carb diet and I’ve now gone to a low-carb diet, and I wrote some articles and the first response was I lost all my funding like that and I was killed. I was dead in the water.
And then my university kicked me out. Well, they didn’t kick me out, that I just retired and they exposed me in the press and say I was no longer believable because I was promoting a diet on the grounds that had reversed type two diabetes and that was a ridiculous claim and so on. And then I had to go to court to fight for four years because what they’d done, they tried to destroy my career. Now during this time, low-carbs, my type two diabetes reversed and eventually in 2018 won the case and it was all over. And for once I’d actually learned a bit about nutrition, I thought I knew about human nutrition, but I really didn’t cause in medical school we don’t literally learn it. And I’d maybe studied carbohydrates during exercise, but I didn’t understand the whole body nutrition. So then what happened was Philip Prince and your guys came and spoke.
Philip phoned me and said, Tim, I’d really like to do some research with you. I met him I think in Ohio at Jeff Volek’s conference, and he said, what should we do? So I said, well, let’s do a 5K time trial because your team is really good at doing 5K time trials on the treadmills. So I said, let’s do that and see what they burn. And so I honestly didn’t think that we’d find the result that the 5K time trial was identical. We’d also done a VO2 max test before and at the end of the trial on both diets, and I looked at Jeff Volek’s book, not his book, but also his research and particularly the faster study. Cause he’d also done VO2 max testing. I thought, I wonder if he’s ever looked at the so-called crossover point, the point at which you start to burn more carbohydrate than fat.
And he hadn’t done it. So then I said, well, why don’t we just look at those data? So Philip did that and produced a really good paper showing that the crossover point shifted far to the right to about 85% VO2 max, which is when you’re not meant to be burning any fat. So we published that one. Well, okay, if it works at five kilometers, maybe it’ll work at one kilometer because that’s a real test. So we did the one kilometer time trials and found no difference, but I’d warn him, I said, but if you find no difference what the people will say, it’s because the athletes had lots of glycogen even though a low-carb diet had enough glycogen for 1K or one mark.
Josh Clemente (00:09:03):
And just to clarify for those listening, so what you mean by no difference, it’s no difference in performance on the one kilometer time trial between the high-carb, low fat and low-carb high fat groups.
Prof. Tim Noakes (00:09:13):
Correct. Thanks for clarifying that. Then I said, so why don’t you do six times 800 meter repetitions? But I didn’t say, and he decided to do this on his own. I didn’t say measure oxygen consumption and metabolism, which was the key thing. So anyway, surprise, surprise, there was no difference because what should have happened, according to the traditional hypothesis, after about three sprints, 800 meter sprints, their performance should have gone down in the low-carb group because they’ve got no more glycogen left. You can predict they’d run out of glycogen after about three 800 meter repetitions. It didn’t happen. They stayed exactly the same regardless of diet.
But then the real killer was that they measured the oxygen consumption and the respiratory quotient from which we can calculate, as you know, carbohydrate and fat oxidation and the carb fat oxidation just went up and up and up and up and up. So the more repetitions they did, the higher the fat oxidation, and by chance, by chance they were exercising at 86% VO2 max. And the textbooks say, at 85% VO2 max, you burn no fat. That’s what the textbooks say, the highest rates of fat oxidation in history, exactly the point where they’re not meant to be burning any fat. So…
Josh Clemente (00:10:38):
Prof. Tim Noakes (00:10:38):
So what that shows is that muscle glycogen doesn’t have an obligatory role during exercise performance. There’s no obligatory role.
Josh Clemente (00:10:49):
Even at these high intensities, which is really the focal point here. Yeah.
Prof. Tim Noakes (00:10:53):
Correct. And so therefore, when one goes back and looks at the original studies, which claim that there’s this specific obligatory role for carbohydrate, for muscle glycogen, by chance, I’d done this before the studies. So I knew that the evidence was there. In those original trials done by the Scandinavians in 1967, they showed that at the point of exhaustion, even though the guys had low muscle glycogen, their blood glucose levels were incredibly low. So they were all hypoglycemic and you won’t believe it. But yesterday I looked at those same studies and I looked at their metabolism at the point of exhaustion in people eating a high carbohydrate diet, mixed carbohydrate diet and low carbohydrate diet. And there were big differences in muscle glycogen and exhaustion, which doesn’t fit the model. There were big differences in fat oxidation, and exhaustion, which doesn’t fit the model. And there were big differences in carbohydrate oxidation, but the one thing that wasn’t different was the blood glucose concentration.
And so you need to look at the variable that’s not different, that is the same because that’s what is going to be the limiting factor. And it was very clear that it was blood glucose. I then went and looked at a whole bunch of other studies, and I now know that when you take carbohydrate during exercise, all your carbohydrate load before exercise, all it happens is during exercise you substitute a little bit more carbohydrate for a little bit less fat. And the kilojoules absolutely matched. So if you burn an extra, let’s say five or eight kilojoules per minute, which is a trivial amount, it’s a trivial amount of carbohydrate, you burn eight kilojoules of fat less. And what we’ve been told since the 1980s, since the sports drink industry got involved, they said without measuring it, they said, but that’s the difference.
It’s this extra carbohydrate that you’re burning in the muscles. This makes you perform better. So now if someone must tell me why burning eight kilojoules per minute more of carbohydrate, which is only 10, 15% of the total energy that you’re expanding at that time, why is that so special that you couldn’t make it up with fat? And what we’ve proven now is that you could make it up for fat, but what was happening was these people were hypoglycemic. And that’s if you take carbs, you can go longer because your blood glucose is higher and your brain still functions. That’s what I know. And so I’m working very hard on a couple of articles which really definitively show that it’s blood glucose, which is the, it is the obligatory fuel. It’s not muscle glycogen.
Josh Clemente (00:14:04):
It’s fascinating. And I think we went pretty deep there and I’m very excited to kind of break that apart a bit more for people. So showing that these assumptions that have been around from the beginning for many of us, of our exposure to the sport, these assumptions were ingrained like law about what the body needs in order to perform. And finally having better tools, better techniques, and honestly better questions to then go and explore is really interesting because it’s overturning many of these laws. So I’d love to hear a little bit. So let’s dig into, for people that are listening who aren’t as familiar with the metabolic concepts here, essentially there are two fuels that we are running on.
We’re running on carbohydrates and we’re running on fats. And what we, through this research are seeing is that the body can adapt from the carbohydrate reliance towards the fat reliance at all intensities of exercise. It used to be believed that above a certain threshold of effort, you have to run on carbohydrates. And you’ve now shown through your research that that is not true. Now what I’m interested in is there is that limiter that you brought up at the end, which is the transition to blood glucose as the limiting factor. And a lot of us think of glycogen and blood glucose almost as proxies for one another. So can you break this down for us? What’s the difference here and what’s happening?
Prof. Tim Noakes (00:15:22):
Sure. Now, and when I started looking through this literature, I believed exactly the same as you. And what we do as physiologists, as you know, we say it doesn’t matter if it’s the carbohydrates coming from the muscle or from the bloodstream, the regulation is the same. And that’s totally false and it took me a long time to realize it. So what happens during exercise, your muscle glycogen drops down as a sort of linear function of the duration, which tells you largely that the exercise is regulating how much glycogen you are using. But it’s going down, it’s always going down. I did not know until six months ago that the glucose that’s coming out of the liver into the bloodstream is now circulating to the muscles and it’s getting used by the muscles, but the regulation is totally different. Why? Because blood glucose oxidation just goes up, increases, and that’s paradoxical because you don’t really want that to happen because the poor liver is becoming more and more depleted of glucose and glycogen.
It’s having more and more difficulty to produce glucose. And the muscles are saying, I don’t care about you, I want that glucose. And ultimately you will always reach the state where the muscle demands more glucose than the liver can provide and your blood glucose will fall. Now, the brain’s not so stupid that it says, okay, the blood glucose is falling, we must just continue until you die because the glucose in the bloodstream is crucial for all of the brain function. And so the brain has a protective mechanism. And in all these studies you can see as the glucose starts to drop, the power output of the athlete starts to drop as well, and they start to get the fatigue symptoms. But if you give them glucose after 10 minutes, the glucose starts to rise and they feel fantastic and they can go on for a long time.
So it’s very clear to me that the regulation is different. And then the next question is why is the regulation different? And I’m now speculating. So what we’ve shown when you’ve been crucial to this as well, what we’ve shown is that the blood glucose is crucial and that the body will burn the glycogen, but it could burn fat for everything. So why doesn’t it? Why doesn’t the body just burn fat? And one of the keys that I observed was that in the studies where people are studied at rest, 50% of the energy is coming from carbohydrate. Now that does not make sense because this is the jet fuel that the body’s trying to conserve, and that’s why you’re filling your mouth with carbs to provide the muscles with carbs and glycogen and the body’s wasting it by burning it at rest and when you’re sleeping, why? And the answer is very simple and it’s provided by George Cahill who wrote this in 1971.
He gave one of the famous lectures in 1971 and he said, the first rule in metabolism is that the body regulates the blood glucose concentration and keeps it within a narrow band. And everything’s focused on that. And as soon as the glucose goes out of sync, the body responds dramatically to try and get it back into range. The one way you can get the glucose back into range very quickly is you dump the glucose somewhere and you dump it into the muscles. And then the body’s so clever that it says, okay, we’ve got too much glucose or glycogen in the muscles. I know you’re going to go out and have another Coca-Cola and you’re going to have some chips and bananas in three hours time. I’ve got to anticipate that, I’ve got to get rid of this glucose in the muscles, so the next load that comes in, I can store it.
And that’s what’s happening. The only reason you burn glucose is to regulate your blood glucose concentration. That’s why you burn glucose. What happens in the body is that the muscles respond, and if they’ve got lots of glucose, they will burn glucose. They have to. And the only way you can stop that is by not eating carbs. And then your muscles are full of fat and very little carbohydrate and then you will burn fat. And something, which I didn’t really catch onto until two years ago, we studied an athlete who was as a low-carb athlete, but he was a really good athlete and so he could cycle at a very high rate from the moment he cycled. And we had him do a 100K time trial, and from the instant he got on the bike, he was burning 1.7 grams of fat per minute, which normally if as you know, if your carbohydrate adapted, you would never get anywhere near there.
But if you’re carb adapted, you start at 0.4, 0.5 and it takes you hours, hours and hours and hours to get anywhere near. But the moment he got, he was burning 1.7, we subsequently did studies to prove it that the content of muscle glycogen determines how much fat and carbohydrates you burn. And so now the final little story. So I went back to those original studies, the 1967 studies, and I looked at the group who were on the low-carb diet and although they could only exercise for about an hour, they had a rate of fat oxidation, which was higher than anything that had ever been reported. But they didn’t notice it because they were focusing on the carbs. And so from the word go, they were burning a whole lot of fat. Now they were not fat adapted, which is the other interesting point. These people were athletes or probably just general people.
Josh Clemente (00:21:37):
Prof. Tim Noakes (00:21:38):
I think they were policemen or something, I can’t recall what they were, but they were burning fat even without being fat adapted and so hard. What I interpreted that to mean that I interpreted it to mean that the body’s designed to burn fat. And the only way you don’t burn fat is if you’re eating high carb diet. So the natural state is to burn fat. You don’t need to train for it. It develops. And Louise Burke has shown that she took some Olympic athletes who are high carb athletes within five days they were burning 1.6, 1.7 grams per minute. They didn’t need to go out and train.
Josh Clemente (00:22:12):
So the theory is kind of evolving towards what we are seeing is actually an adaptation towards carbohydrates that we’ve induced. We think it is the natural state, but actually it might be that that’s upside down and in fact the natural state would be fat oxidation. And I have a question that I think will lead into this in just a minute, that I would like to get into to kind of determine what nature’s preferred fuel substrate is and why.
And I think there’s an interesting question varied there, but one last thing I wanted to touch on that we kind of mentioned and moved past is the question of why doesn’t the body just burn fat even when fat adapted? So even when we really fat adapt, we will never go to zero glucose in the bloodstream. We’ll always be producing glucose and maintaining it in that very tightly regulated band that George Cahill was describing. And can we answer that for the listeners? Why is it that the body will never get to, even in the most fat adapted state after 30 years of eating a high fat, low-carb diet, will we never get to zero circulating glucose?
Prof. Tim Noakes (00:23:13):
Okay, because glucose is obligatory for the brain. And that’s why I think that the glucose oxidation goes up during, a blood glucose oxidation goes up during exercise that shows obligatory you can do what you like, you can’t stop it. You can take all the carbs you like, you won’t stop this, it’s going to go and you can start exercise carbohydrate depleted. And the rate of blood glucose oxidation is the same. So it’s fulfilling some obligatory role and obviously part of it’s brain, some of it may be kidneys, some may be other tissues, and it may also be obligatory for muscle, I’m not going to exclude that, but it’s such a tiny amount that it’s not as we used to think that it’s the predominance source. It’s a tiny, tiny amount and I’m not excluding the possibility that you need a little bit of carbohydrate to keep muscles working properly.
Josh Clemente (00:24:07):
Yes, thank you for clarifying that because I think that’s a really crucial point, which is that we don’t want to get over hedged in one direction or the other. And the fact is that we have been in one direction as somebody who has tried to train in various ways over my lifetime and trying to replicate what I see the elite athletes doing, assuming that that’s what’s best, it really leads you to a very carbohydrate heavy fueling strategy because that’s really, you know, see somebody in the gym on training for the Tour de France pipeline and the way that they’re consuming calories, the vast majority in those training cycles are carbohydrates.
And so people, we have this tuned, the whole culture is oriented around that. And it’s not that we should overcorrect in the other direction, it’s that in fact the science probably shows that we’ve adapted to operate in that environment and we should likely, we need to understand what the natural adaptation is. And we know however, that glucose will never go away, always going to be a critical element for brain fuel. And the interesting thing I think is also we think about the brain and how it has a critical fuel dependency on glucose, but the heart has a critical fueling dependency on lipids, on fats, right? I believe the muscle tissue in the heart almost exclusively oxidizes fat. Is that correct?
Prof. Tim Noakes (00:25:27):
You know, it’s really interesting cause my PhD was actually on little rat hearts, which we got to contract, we had them pumping as if they were in the animal and we’d stressed them. I developed the system for testing them to their maximum output, and I measured what they fueled preferred, and the answer was, it was glucose and insulin were actually the best. But ketones worked also very well. The problem in the model, it’s difficult to study fat metabolism for various reasons. We have to bind fat albumin, and that changes the whole characteristics of the fluid that you’re pumping, that the heart is pumping and it changes the dynamics. But glucose and lactate and instant and ketones the heart love to order them. It just depended what you give it. It’ll burn. Yeah.
Josh Clemente (00:26:12):
Okay. So it’s hyper flexible. Well I think the, to kind of shape the conversation a bit further, I’d love to talk a little more about the findings and how you would say these apply to various groups of people who are likely listening to this conversation. So this group was specifically recreational male athletes that we studied. And I know there’s a lot of research that goes in with various demographic cohorts, but how would these same findings, in your opinion, apply to elite athletes? And then I’d like to also hear from there how you think it would apply to female athletes specifically.
Prof. Tim Noakes (00:26:49):
Okay, so let me ask that question first, you’re quite correct because you saw the athletes and they were recreational, but they were actually better than 88% of all American runners. So although they’re a recreational, elite recreational, and so therefore 88% of American runners, and that applies to runners across the world, I would think could benefit from the start in other, or sorry, they didn’t need to eat the high carb diet. There was no difference in performance. So now you say, okay, what about the other 12%? Well, when you look at Eliud Kipchoge and he runs his marathon in two hours, I’m rewriting Law of Running and I came to realize that it’s pointers saying, oh, he is running at a VO2 max or a VO2 of such and such. What you want to know is how many kilojoules per minute is he expending, and where are those kilojoules coming from?
And it turns out that because he’s only 52 kilograms, he’s actually only burning 78 kilojoules per minute, which is two grams of carbohydrate, so two grams of fat per minute. So technically he could run the marathon on fat if our model is true. The problem is that he’s been raised on a high carbohydrate diet and the Kenyans run on a high carbohydrate diets because that’s available to them. But I will guarantee you that their diet has changed in the last hundred or 200 years. That 200 years ago, many of those, the African runners came from generations who were cattle wrestlers and they were eating animal-based diet, I would guess. And it’s only more recently that they’ve moved to the high carbohydrate diets.
Josh Clemente (00:28:39):
I mean, it demonstrates the pretty amazing flexibility of the body to be able to perform right and whatever the sort of environmental circumstances provide.
Prof. Tim Noakes (00:28:49):
But for another second…
Josh Clemente (00:28:50):
Prof. Tim Noakes (00:28:51):
So one of the other studies I looked at in detail was the first study to show that carbohydrates ingested during exercise could improve performance. And it was studied, written by Ed Coyle 1986, and we published another paper in 1986 trying to prove that hypoglycemia could be reversed in performance and we couldn’t find it because our model was wrong. He got into the laboratory and did the best way to do it. He starved the people for 12 hours before exercise. That was the key. But I went back and worked out the metabolic state of those athletes as well, and I noticed that they didn’t report the actual fat oxidation rates. They reported the carbohydrate oxidation rates, and they had a picture showing carbohydrates, fats and muscle glycogen oxidation. When I made the calculations, I showed that these people were the ones when they took carbohydrates, they were burning fat at 1.2 grams per minute, which was the highest value ever reported at that time, and no one noticed it.
So who were these athletes in 1986 who were burning so much fat? The answer were there were Olympic class elite cyclists in Austin, Texas from where Armstrong arrived, Lance Armstrong comes from there. So they’re obviously very competitive. Ed Coyle got some of the best cyclists and they were fat adapted in 1986. Why? Because that was before the carbohydrate craze hit. I think that was the one reason. Secondly, because they go out into long cycles, and I’ll bet if you studied the Tour de France cyclists, although they’re eating high carbohydrate diets because they cycled for five or six hours frequently they’re fat adapted as well. That study shown even eating a high carbohydrate diet could be fat adapted. And clearly they were doing some training that wasn’t being done by everyone. And a runner, a runner can’t run for six hours. So a runner is less likely to be fat adapted than a cyclist, in my opinion.
Josh Clemente (00:30:56):
When you say a runner can’t run for six hours at a certain intensity level?
Prof. Tim Noakes (00:31:01):
I’m talking about training. I mean, I think the Tour de France cyclists the hardest, they spend the most time on the bicycle, so they’re going to burn through carbohydrates and get into that fat burning zone much more frequently than runners.
Josh Clemente (00:31:17):
It’s essentially that given this certain work exercise domains, you can essentially outpace the dietary substrate that you are working from and then your body kicks over into the adapted state depending on which, on a bike you can produce 350 watts of power continuously. You don’t need to and most people do not do that when running, like you said with Eliud Kipchoge, he’s burning, his actual power output is actually quite low given that he’s does not weigh a lot and he’s kind of moving very efficiently. So it’s really interesting.
Prof. Tim Noakes (00:31:54):
So one of the first people who contacted me, one of the first elite athletes contacted me was Dave Scott, who won the Ironman five or six times. And he said, Tim, if I’d followed your diet in the 1970s, I would’ve gone 40 minutes faster in Ironman. He said that that was the worst mistake he ever made was to eat the high carb diet. And there’s another lovely story that Paula Newby-Fraser who won the Ironman eight times and who won 28 Ironman triathlons, she’s actually from South Africa, and she was such a talent.
She went to America after one year of training, came third in the Ironman the first time, and then that was in 1984 when Jeff Volek’s, sorry, not Jeff Volek, Steve Phinney’s first paper came out saying, you burn more, eat more fat. And she phoned me and she said, Tim, I’ve read this paper. What do you think? Should I eat more fat? I said, yes, Paula eat more fat. But at the time I was promoting the high carb diet and she interpreted as she should go on a low carb diet. She went on the low carb diet, she won all these on Ironmen. And when she retired, she said, the best piece of advice I got was to eat the low carb diet. And I said, Paula, but I never taught you that.
Josh Clemente (00:33:05):
What a funny coincidence. That’s wild. Yeah. Well, that’s a great transition from elite athletes and specifically female elite athletes and how clearly that was a success story for her. How about if we take the recent results of the research and discuss how do these results, which were entirely male recreational athletes, how do you think that applies to female athletes? Do the same sort of biochemical principles we discussed here, hold for both sexes and what do we yeah, love to hear your thinking there.
Prof. Tim Noakes (00:33:38):
So when I was running marathons more competitively in the 1970s, there was a guy called Doctor, it wasn’t Atkins, he was a German doctor and he came up with a theory and he said, women are going to outrun men. And why was that? He said, because women burn more fat when they’re running and they’ll have better endurance. So that was the theory in the 1970s, and I don’t know if it’s been shown since then because I think you burned fat on the base of your diet. So he was probably studying women who were eating more fat in their diets. I can’t see any reason why there are women’s muscles would be different and would metabolize any differently than men as far as the energy metabolism goes. So I would think it applies to women. But what I would like to say is that having developed type two diabetes as a result of following this low-carb diet, sorry, the high carb, following the high carb diet and running 70 marathons or ultramarathons and still getting type two diabetes, I’m a bit more suspicious about the health effects of the diet.
And the study that we did also showed that 30% of these recreational athletes became pre-diabetic on the low carbohydrate diet, whereas when they were eating the high fat diet, low carbohydrate diet, sorry, let me get that right again, when they ate the low fat, high carbohydrate diet, they became pre-diabetic, when they ate the high fat, low carbohydrate diet, the control was absolutely perfect. And Andrew Kutnik, who was crucial in this analysis showed that those athletes who burned the most fat were the ones whose glucose control improved the most when they went on to the high fat diet. So that was the first time linking fat, oxidation and muscle with more resistance to type two diabetes or pre-diabetes. From that study, the first study showing pre-diabetes developing without people putting on weight, changing their diet or changing their exercise habits, the only thing they changed was the diet.
Josh Clemente (00:36:00):
And this is shown through the continuous glucose data that the athletes were developing during the, so it was a crossover trial. So essentially we had a low-carb, high fat group and a high carb, low fat group, and then they crossed over at the midpoint. So they each did that diet for four weeks, then they switched and did the other diet for four weeks. And so what you’re describing there is an actual onset of these abnormal glucose dynamics as tracked by a continuous glucose monitor during the high carb, low fat portion. Is that right?
Prof. Tim Noakes (00:36:31):
That’s correct. So I spend my life now telling people that the key to being healthy for metabolic health is you’ve got to titrate how much carbohydrates in your diet and how much you can cope with. And so those three athletes of the 10 on the standard diet, were eating too much carbohydrate and the body couldn’t regulate their blood glucose under those circumstances and that’s going to harm them. They will become diabetic in once they keep on that diet for 10 or 20 years, they will become diabetic. Now, do they represent all runners in the world? I would say they probably do that 30% of runners eating this high carbohydrate diet in their thirties or forties, if we tested them properly, we’d show that they pre-diabetic. And the other thing which people don’t perhaps understand, but when we started running in the 1970s, you trained really hard and at the end of three hours, that was the end of the race.
I mean, if you hadn’t finished within three hours, there was no one hung around to see you finish in six or seven or eight hours. They were gone after three hours and everyone was lean, but really lean because they trained hard, but they didn’t eat so much carbs. Now you go to these marathons and you see that people finishing six hours, they’re a metabolic disaster. They’re carrying all this extra fat, but they believe because they’re running, they’re going to be healthy. And that’s not true. And then we are telling, not we, but others are telling them to eat high carbohydrate diets to run faster. So to get back to your point, I would say that the only people who can eat high carbohydrate diets as runners is those who prove they’re not pre-diabetic or not going to become pre-diabetic. You have to earn your carbs by being healthy if you’re not healthy.
And it’s a simple, if you’ve got visceral obesity, if you’ve got a tummy and your waist is too wide, carbs are killing you. And people have to understand that. And the reason why I’m so vocal about this is I watched my dad die from type two diabetes and I couldn’t help him because I didn’t understand and it is an awful, awful death. And that’s in a sense why I came out and said I was so wrong about the diet because I knew that a lot of people will become diabetic, if they follow the dietary advice I was giving. And I hate to say, listen, I’m terribly sorry I was wrong. I don’t want you to die. I don’t want you to be sick as a result of this.
Josh Clemente (00:39:03):
I want to do two things here. Firstly, try to draw a distinction between all carbohydrates and the ultra processed stuff that people tend to, if you look at the world of sports, as somebody at my fittest point in my life, in my mid, late twenties, I was working out CrossFit, CrossFit trainer. I had a lot more muscle on than I did than I do even now. And I’m in decent shape now. When I first used a continuous glucose monitor, I immediately recognized that I was pre-diabetic. I mean my blood sugar was quite chaotic. And what I was doing was following again the best practices of the sort of sports science around me, which was a lot of very processed carbohydrates before workouts to carb load. A lot of processed carbohydrates after workouts to glycogen replenish were the terms I was using a lot of sports drinks that are loaded up in very fast metabolizing glucose in fructose.
And so I was constant bar bombardment to my system and my body just simply couldn’t keep up. And even though I was not showing the visceral adiposity, I wasn’t showing any of the signs that you would look at and say, oh, that person is at risk for diabetes or pre-diabetes, my blood glucose dynamics were horrendous. I’ve done a bunch of things personally, and again, this is an end of one, but I’ve gone all the way to the other direction, ketogenic, lots of running, lots of zone two, lots of fasted exercise, which I would love to touch on in just a minute. And now I’ve come back and sort of balanced where I, like you’re saying, titrating the carbohydrates and very, very specifically picking the carbohydrates that I know I can trust. The ones that are not going to be an assault on my bloodstream, they’re going to break down in the context of fiber in a whole food.
And this tends to be berries, it tends to be sweet potatoes or something like that. Every once in a while I’ll make some rice or even some pasta when I want to indulge, but I’ll be very careful about what grain varieties I pick. And anyway, all that to say I do and I pick the portion size based on how active I’ve been, how much I’m expending, how much my body is sort of depleted. And I think that’s maybe an important point. I would love to hear your thinking on that. When we’re talking about carbohydrates, how much are you indexing on the type of carbohydrate, the processing versus just the overall sort of macronutrient itself?
Prof. Tim Noakes (00:41:17):
Yeah, I think you’ve made all the valid points that you need to make, that you have to be very cautious and not eat ultra processed foods. So again, very important advice. What I do think one of the problems is ultra processed foods is the addiction and that that’s also a problem. To me, obesity is an, it’s largely based on addictive foods and the ultra processed foods are designed to addict you. So that’s one of the problems. So if you’re running and what you said is that depending on how much you’re running, that’s fine because you burn off the carbohydrates. And it’s really interesting that when I was running, I was clearly pre-diabetic because the only time I would start to feel good was after running about four or five hours and then I think I went into ketosis and my glucose finally stabilized and my body felt much better doing a little exercise didn’t help.
It had to be a really long exercise. And then when I trained really hard up to 150 kilometers a week, then I felt good because now I was burning all those carbs was just going out of the body, I was burning it immediately. The minute I stopped, I know I couldn’t believe how quickly I would put on weight. It would just, within a month I would’ve put on three, four kilograms. I couldn’t believe it. Yes. And now understand why, because I couldn’t regulate my blood glucose. So it was just packing the carbohydrates into fat.
Josh Clemente (00:42:43):
Yeah, that’s so interesting how quickly these things change. And I think let’s talk a little bit more about the glucose dynamics during exercise. So a lot of people that are listening to this have likely tried a continuous glucose monitor themselves. So they’re listening to the results of the research that you showed, which show that with high fat, low carbohydrate diet, high intensity performance is not reduced relative to high carbohydrate, low fat. And the glucose dynamics that we saw, we sort of touched on this a bit, how glucose glycogen reduces in the muscle, how glucose trends in the bloodstream.
Some people who are using CGM see varying results. I myself, at a certain intensity level start to see my blood sugar dramatically increase. And so I’ll have in some cases over 200 milligrams per deciliter, which what is that? That’s like over 10 millimoles of glucose in my bloodstream just from a workout, fasted. And that’s a very high intensity. So can we touch on that a little bit more? How should people, like what’s going on there? And then also how should people think about those glucose spikes in the context of their overall health?
Prof. Tim Noakes (00:43:47):
I think that people who are pre-diabetic are the ones who will raise their glucose during high intensity exercise. I noticed that on myself when I was a 28 year old. We were doing studies in low, believe it or not, low-carb diets and on a high carb diet, my glucose shot up and during exercise and it shouldn’t do that even during prolonged endurance type exercise, which wasn’t my glucose rose and I didn’t spot it because all the data I had seen up to that point said that the glucose stays normal during prolonged exercise. So I knew that I was insulin resistant. And so I’ve kind of interpreted that to mean that that’s actually a marker of the pre-diabetic state. Even more reason why you need to keep your carbs down if you see that spike during high intensity exercise. Do I think it’s serious?
Probably not. It’s the sustained glucose with the high insulins. One of the other things I’ve learned in the last few months looking at the data is what is astonishing is how quickly your insulin drops during exercise. You can start with an insulin of 60 units, which is extremely high because we are trying to get down to six units in the units we use. So it can be 10 times normal, but it’ll be back to normal in 10 minutes of exercise. So the best way to lower your insulin apart from not eating carbs is actually the exercise. So I would think that although your glucose is going up, your insulin’s coming down and probably the insulin is more of a problem. And also high intensity exercise didn’t last too long, so you probably won’t have high glucose for too long. So to summarize, I would say if you’re getting a high glucose during exercise you’re pre-diabetic probably, but we’re talking about 20 years forward, we’re not talking about tomorrow. And if that’s, you’re just an insulin resistant person and you need to interpret that appropriately.
Josh Clemente (00:45:43):
So should people expect over time given let’s say the same intensity if they were to adapt to fat oxidation, So start eating a say higher fat-based diet. Should someone expect that those glucose spikes would reduce over time given the same intensity?
Prof. Tim Noakes (00:45:59):
Yeah, that’s what one would assume. And again, from the data that we have, we saw normalization even during exercise, there was a greater return to normal. So I would expect that, I can’t see why if you’re not eating too much carbs, you should have these abnormal glucose spikes.
Josh Clemente (00:46:20):
So from my own kind of one research on myself, I will say that I’ve seen a reduction over time in the sort of absolute peak of those high intensity spikes. So I’m going to have to dig into this a bit more and see how that trend is looking. We’re short on research on this matter, but ultimately it does look like, well first of all, we know fundamentally it’s totally different to be experiencing elevated glucose from sort of sitting on the couch drinking a Coca-Cola versus pushing weights around or running at a high intensity. So just what’s happening biochemically in the body is totally different. And I think that the insulin level is, that’s a great way to think about it, is just your insulin also being elevated.
Prof. Tim Noakes (00:47:00):
By the way the, I’ve just had this thought, I must tell you that the guy who set the new world record for the Ironman, you know that set up where they had guys helping them and I think he did under seven hours. He showed his blood glucose concentrations and they were all over this. They were unbelievably elevated, they were pre-diabetic. And he said, see, I’m never going to become hypoglycemic. I realized actually your problem is hyperglycemia. So he must have been loading up on the carbs to great excess, completely unnecessary.
Josh Clemente (00:47:34):
I wanted to jump ahead into one other question that I know is going to be top of mind for listeners, which is the low-carb, high fat exercise versus fasted exercise. So how a lot of people are now, myself included, including and incorporating fasted exercise into our routines. I personally feel really good when I’m going to do say prolonged zone two exercise, doing that fasted versus doing it after any type of meal, high fat low fat doesn’t really matter. How do you think about fasted exercise in the context of adaptation and improving metabolic function, metabolic fitness?
Prof. Tim Noakes (00:48:09):
Well, I just think fasting is really healthy and combining it with exercise would suggest to me that you’ve got a double benefit. I don’t have any evidence that that’s the case, but I do know that fasting is one really good way to help reverse metabolic syndrome. So I think that stressing your body in those two ways is very helpful. You see the irony is the greatest threat to the body is not starvation or fasting. It’s high carbohydrate diets. And that’s, people don’t understand that. By the way, by starvation, I mean a few days of not eating, but the thing the body can’t cope with is a high carbohydrate diet. It can cope with fasting. The world record for fasting is like 380 days, but that guy was, he had a lot of fat on him to burn off. So…
Josh Clemente (00:49:00):
Yeah, it’s a fascinating story. So I think his name was Angus Barberry and just took in minerals and water for 380 something days and yeah, really fascinating. So I think that the evidence is very clear that, fasting is not an acute danger of course considering the individual circumstances and everybody is at a different starting point. And hormones also really play a role here. And I would love to jump into that just a minute, but stepping into the next question here as I know, I want to be mindful of your time. One topic that has come to my mind repeatedly when thinking about why the body does so well in low-carb adaptation is did evolution select for the most efficient fuel by default? And what I mean here is for each gram of fat, you get nine calories of energy and for each gram of carbohydrate, you get four calories of energy.
That means that if I’m the body, I’m evolution trying to figure out what fuel should this body carry around with it, what’s going to be most efficient? Well, I’m getting 2.2 times more energy per gram of fat that I carry. So we now know that when you look at an average person, let’s say someone who weighs 150 pounds and is 20% body fat, that person is carrying over a hundred thousand calories of fat energy. And if they were carrying that same body weight in glucose or glycogen, they would only be carrying about 30 to 40,000 calories. So it would be much lower efficiency in terms of you’re carrying that weight around and how much energy it contains. Is this something that you think about? Does that factor in at all? And how do you think about the evolutionary context for why the body prefers which substrate?
Prof. Tim Noakes (00:50:41):
So I’m sure we all have the same slide, which is how much carbohydrate you store in the body and how much fat you store and it’s, they just look and then you look at that and that’s the great question you’re asking, why do you so much store so much as fat? And then what you didn’t mention is when you store the water carbohydrate, you store water with it as well. So that, and I used to think that that was the reason that you can’t store much energy as carbohydrate because it’s full of water. I think that evolution adapted us to eat high fat, high protein diets. And there were two papers published in the last month and the one was 120,000 years ago and they showed amongst the fossils that they were looking at were elephants and they looked at the elephant bone, which is the foot bone.
So it’s like the toe is down there and below that the elephant has a huge pad of fat, but it’s a big bone like this and below it’s a lot of fat. And humans obviously liked fat because if you looked at the bones, it had cut marks on it. So humans had specifically gone and cut that, the bone, cut to get the fat away, but it was an elephant 120,000 years ago, humans hunting elephants, how did they do that? They didn’t have guns. So they did something very clever. But now the last paper came out also, I think last week, 3 million years ago, Paranthropus who was one of our predecessors, not yet human was killing rhinoceros’. So they found rhinoceros bones with these cut marks showing that humans had taken the meat off these bones. How do you kill a rhinoceros when you’re Paranthropus and our guess is probably five foot tall.
But the point was that’s what we grew up on. We grew up on fat and protein diets and that’s why we developed the gut and our brain as well. So I think we’ve been adapting for this for 3 million years to be adapted to burn fats and not carbohydrates. Carbohydrates as you know, come into the dire 12,000 years ago with the agricultural revolution. And they came in because we ran out of fat animals on all the continents. We just didn’t get enough fat. So now we had to find something else and we couldn’t eat lots of protein because our bodies are not designed to cope with too much protein. So what was obvious we had to get was some carbohydrate. And so that became cereals and grains.
Josh Clemente (00:53:31):
I think looking at the timescales and the availability of first of all carbohydrates that scale throughout the year, I mean that is very seasonal to be able to come across high carbohydrate foods. But just even if we look at carbohydrates as a basis of energy for tens of thousands of years, maybe even hundreds or longer, if you consider that timescale, the past 100 years is still a black swan event in terms of how much processed sugar and carbohydrate we can get into the bloodstream in how much time, right? In 15 minutes I can consume more sugar direct to the bloodstream in a liquid form or in a powdered form than most of our predecessors would come across in months or years maybe. So I think that that’s unequivocally the case that we have exponentially increased the load on our systems.
Prof. Tim Noakes (00:54:24):
And just one other point, the populations who converted to high process foods in, if you come to Africa, the populations that started eating sugar and refined carbohydrates, they destroyed their teeth. They didn’t have dentists, so they couldn’t survive. If your diet kills your teeth, you finished because you get brain abscesses and so on. So we know that going back far enough, they couldn’t have been eating a lot of carbohydrate or they would’ve had terrible teeth.
Josh Clemente (00:54:54):
Such a interesting, and we can spend a long time on the history here, but I have two more questions that I would like to take just sort of in almost a lightning round style. The first one is, what’s the most important question you think researchers need to answer next in terms of fuel adaptation, low-carb, low fat. What is the question that’s burning in your mind on the research side?
Prof. Tim Noakes (00:55:16):
Okay, what’s burning on my mind is to get people to accept the data. And the only way we can do that is by having lots of people who previously promoted high carb diets doing research and proving that they were wrong. That’s what we need to do, probably is that’s not going to happen because the industry funds people to study carbohydrates. And that’s partly the reason why carbohydrates are so dominant. And I’m pointing to that because we were funded by the carbohydrate industry for 15, 20 years and we did fabulous studies, which I now realize were really amazing. But they were all looking at carbohydrate metabolism. And only right at the end did we do some studies where we did low-carb studies and they were critical. They were absolutely critical because they showed where the controls were. The controls were that if you had high muscle glycogen, you burn carbohydrates.
If you have low muscle glycogen, you burn fat. And even insulin isn’t the main driver, it’s what’s in the muscle at the start of exercise. Insulin helps and glucagon helps, but it’s the driver is in the muscle itself. So I think that’s what I’d like to see because I think runners are getting the wrong advice and their health being affected as my health was affected. And I just wish that I’d known about this high fat diet when I was running in, when I was 20 or so because my career would’ve been very different. I would’ve run many more ultra-marathons successfully because I just tailed off very quickly as the more carbs I ate, the more pre-diabetic I became and the worse my running went. I will just tell you that lovely story. So one of the Indian diplomats in Cape Town, I’ve become a great friend of his and Indian people, as you know, eat vegetarian diets.
And he read about this low carb diet and he was a runner and he wondered, wonder what happens if I switch from being a vegetarian. So I said, well, it’s not going to harm you, might help. And he switched to become a carnivore, an Indian carnivore. And he said, it’s terribly difficult because whenever I have all my friends from India come out to meet me or the other important people from India, we have to provide them with the conventional vegetarian diet. So he’s converted to this diet, his performances are just going up and up and up. And he sends me an email every few months as he’s done another race. And the funny thing is, the people he trains with eat high carb diets and when they race, he just leaves them all behind. They can’t understand. They said, but how can you run like that if you’re not taking in carbs? They just don’t get it.
So let me tell you what I would like, a study I would love to do was to see what happens if you’re high carb adapters after three hours of exercise. Because if you’re going along burning, you suddenly run out of glycogen. You can’t burn fat because fat, you don’t, your body’s not designed to burn fat. You have to slow down. You absolutely have to slow down. But if you’re burning fat from the start, you find cause you are one to two grams of fat’s going to get you right through three or four or five hours. So at the moment, I don’t believe that your diet plays any role in your performance that’s an important point to make. Its industry made us believe that carbs make a difference and we’ve shown they don’t. However, if you could get athletes to do four or five hours of exercise, I would like to see what happens in a carb adapted athlete.
They’re going along and then they run out of carbs, what do they do? Whereas if you’re burning fat, you shouldn’t have a crisis. You should be able to go on. The problem is no one will run on a treadmill for four hours or five hours. We tried it. We tried a cycling exercise for up to eight hours and we actually did find evidence that the high fat group were doing better, but we only had a few numbers. So the reason I want to do that is because I think that you’re healthier if you’re eating a high fat diet. And I would also make the point that all the studies and laboratories are one off races. What happens over a season? That’s the other question that needs to be answered. Your body’s more inflamed if you’re burning carbohydrates. Dave Scott said that he said he will not tell any of his athletes to eat a high carbohydrate diet because their bodies are always inflamed and they’re more likely to get injured.
Josh Clemente (00:59:47):
I’m sure there are some athletes listening to this who may be interested in an eight hour treadmill endeavor. But we have people in our audience like Mike McKnight, who, he ran a 100 mile race completely fasted and showed with glucose data that his body was able to super effectively manage that situation. And clearly he was doing that entirely on or almost entirely on fat. I think the next question and last question I wanted to wrap on is a really nice mesh with what you were just describing with the research, what we need to show next.
And I think it’s that we’re seeing the ability to take the lab equipment measurement systems and put them on the body directly and now they’re mobile and now we can start to log data in much more interesting environments. And I think the continuous glucose monitor is an example of this. But I would love to ask you, what molecules, in addition to continuous glucose data, would you want to see tracked continuously? If you could just wave a magic wand and you could measure anything about the body and you wanted to do so to demonstrate the metabolic conditions for best metabolic health and also how they affect performance, what other molecules would you be looking at?
Prof. Tim Noakes (01:00:58):
Yeah, I think fat oxidation is the keys. It’s a very important factor. The more fat you can oxidize the job, probably the healthier you are. So that’s something I would look and we actually, in about 1976, we had guys breathing into a and measured their gas exchange in a 56 kilometer race. But we use such archaic equipment that we didn’t get real proper data. So I don’t think there’s an individual molecule that you can look at that’s as helpful as glucose at the moment. But if you could measure your glucose and your fat oxidation at the same time, that would be really helpful. And you could then classify people into the different levels of carbohydrate oxidation, fat oxidation during exercise and see what happens and also see how it tracks over duration. So my prediction is that if you’re a carb adapted athlete and we ask you to run for four or five hours, you’re going to hit some sort of plateau when you run out of glycogen.
And if you’re not fat adapted, you’re not going to be able to burn the fat as effectively as if you’re fat adapted. And that’s where the difference will become apparent. And then of course it extends out further. Now the athlete you mentioned, we have an athlete in Cape Town who cycles about 150 kilometers a day and eats zero carbohydrate. Zero carbohydrate. Now the biologist will tell you it’s impossible, but it isn’t because fat is being, cause they say you can’t convert fat to glucose in the liver and I’m convinced you do. That’s where you can generate your glucose from fat is in the liver and I suspect that that’s happening with these athletes who do not need to eat anything during a hundred mile race. They have to become hypoglycemic. And if they don’t, it’s cause they’re converting fat into glucose, blood glucose. And if you’re doing that, then you’ve solved the problem. You no longer have a metabolic issue during exercise. You can go on forever because you’ve got lots of fat and you’ve got enough glucose to keep you going.
Josh Clemente (01:03:12):
Well, I think that’s as interesting a topic of research as any and also a really fascinating, I think cliffhanger that hopefully we’ll be able to have another conversation and discuss some results in this area sometime soon. This has been amazing. I’m really excited to continue to follow along with your work and I appreciate you coming and joining A Whole New Level. Thanks for making this happen and thanks for continuing to push forward on the science here. It’s really amazing and it’s informative and I love that it’s the cutting edge right now.
Prof. Tim Noakes (01:03:39):
Thanks Josh. Well it’s been lovely and thank you for thinking it through and asking all the relevant questions that I could answer as best I could. And I think we got a message out there and a lot of people are saying that actually they’re going to begin to accept what we found it. There’s going to be resistance because people’s careers have been built on saying carbohydrates are important, but be like me. They need to be like me and just say, okay, I got it wrong. Let’s move on. That’s the way to do it. The quicker we get the message out to the athletes that they don’t need to eat all this carbohydrate and that such a high carbohydrate diet is going to harm the health of most of them in the long term. That’s the message that we need to get out.