Insulin Resistance and the High- Carb, Low- Fat Diet Connection. By Dr. Tim Noakes, a well- respected scientist, researcher, physician and professor at the Division of Exercise Science and Sports Medicine at the University of Cape Town, South Africa, is one of the world's foremost experts on low- carb diets. In fact, he was instrumental in getting the low- carb diet revolution off the ground. He's also an accomplished athlete. As a long- distance endurance runner with 7. Eventually, he discovered this wasn't the best way to improve athletic endurance and health, and ended up writing a number of popular books on low- carb diets. From High to Low Carb. Noakes graduated from medical school in 1. At the time, he was also running, and this was when the high carbohydrate diet really started to become popularized. Following the advice of one of his professors at the cardiology unit where he worked, he changed to a high- carb diet and began promoting it in his writings, including the book, . I continued to do this for 3. He also admitted he was overweight, which didn't help. By chance, that same day he received an advertisement for Dr. ![]() Westman's book, . Despite that, he bought the book, and within two hours of reading, he realized he'd had it all wrong all this time. I started at lunchtime on that day. I've been on that diet now for the last six years. I've dropped 2. 0 kilograms (4. ![]() ![]() My running returned to what it had been 2. But I'm glad to say today all my blood tests are within the normal range. I am taking medication. Anyway, I decided that I'd start reading. I read all your work. ![]() I read all the books. I started doing research. That convinced me that this is a really important change that we need to promote throughout the world. Clearly, the diabetes and obesity epidemics started in 1. It's caused by the dietary guidelines. I slowly began to understand . I only eat between lunchtime and . It's about a 1. 6- hour fast and an eight- hour period where I eat. The success of this book produced major changes in dietary understanding in Southern Africa. Alas, its success also led to legal action being taken against him by the Health Professions Council of South Africa, which is a professional medical licensing and regulatory board. The action came after he posted low- carb advice to a pregnant woman on Twitter. As a result, the president of the Association for Dietetics in South Africa wrote a long letter to the Health Professions Council, challenging his ability to practice medicine. You're not allowed to discuss the diet among the doctors. If you do practice it or if you were to prescribe it, something would happen to you. That's how strong the movement against it is. It's absolutely astonishing. The worst bit for me actually wasn't the trial and being accused of malpractice and so on. The worst bit was my university. The dean of medicine wrote to the local newspaper and said they dissociated themselves from my views and all those who support the low- carbohydrate diet. Low Carb High Fat Diet, LCHF Diet, Atkins Diet—regardless of what you call it, does this eating plan actually help you lose weight? Conclusions. The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six. LISTEN (20 Minutes) Earlier this summer, Steve Phinney and Jeff Volek, authors of The Art and Science of Low Carbohydrate Performance, headed to the Western States.
![]() ![]() Of course, they had no evidence for it, but here I'd worked at this university for 3. That they could do that was absolutely astonishing. He was also cross- examined for three and a half days. ![]() Then for another three days, expert witnesses were heard, including Nina Teicholz, Zoe Harcombe and Caryn Zinn, all three of whom presented a remarkably sturdy case for its use. He just threw up his hands and quit. He didn't have anything to say. Zoe Harcombe was the same. She has just completed her Ph. D., showing there was never any proven evidence to change the dietary guidelines in 1. She presented her Ph. D. Again, the evidence is absolutely overwhelming. The end result is that we've had 2. ![]() We won everything. They have not been able to pin one thing on me. I think it's the first time in history that a diet has been put before a legal jury to decide whether or not it's true. It remains to be seen whether the health professional council, the statutory party that took action against Noakes, will have to change their nutritional guidelines and update all nutrition and dietetics teaching in South Africa. As noted by Noakes, . He went through all the transcripts of the trial, and then began digging into the backgrounds of all the expert witnesses testifying against Noakes. Most of them turned out to be linked to an organization called the International Life Sciences Institute (ILSI), which is a Coca- Cola funded organization. ILSI is basically a front- group for the beverage industry, and has links to Monsanto, Pfizer, Unilever and, in the past, the tobacco industry. Green wrote an expos. Tim Noakes: The Final Crusade. The reason was we were getting too close to questioning the role of sugar and carbohydrates in ill health. We haven't proved it, but there's enough evidence out there to suggest there were things behind the trial that one would not have thought about. In 2. 01. 0, he published . While rarely discussed, exercise- associated hyponatremia — drinking too much or overhydrating — actually contributes to many unnecessary deaths. ![]() Noakes explains. In fact, I ran a 5. I think I had four drinks. You'd have a drink every hour and you would literally swirl your mouth out with water and that would be about it. No one came to any harm. Then in about 1. 97. I began actively to promote drinking during marathon races. I became very active in South Africa saying there was not enough fluid available to marathon runners . They had 5. 6 drinking stations in a 5. At the end of that race, a lady was unconscious. She was hospitalized .. Her blood sodium concentration had fallen. She wanted to know what had happened. She said, 'Maybe I took too little sugar or salt during the race. What should I do about it?' I said, 'I have no idea.'I then decided to investigate. Over the next 1. 0 years, we were able to show that . She'd retained the fluids, . She'd remained unconscious for four days. We provided definitive evidence that it was overdrinking that caused the problem. Still, in 1. 99. 6, the American College of Sports Medicine, funded by Gatorade, produced new drinking guidelines stating that dehydration is the killer when you exercise, and you should drink . In 2. 00. 2, a young female runner died shortly after completing the Boston marathon. Cause of death: water intoxication. As recently as last year, two American football players died from overhydration. An estimated 3,0. Yet, there have been at least 1. How Industry Controls Information. Finally, in 2. 00. American College of Sports Medicine revised their guidelines to what Noakes had suggested, which is that you should drink to thirst. The only reason we could change was because two scientific journals in the entire world were independent of the sports drink industry. In addition to that they are the main reviewers of journal articles. Over a 1. 0- year period, we would submit papers and I knew they went to exactly the same reviewers every time. It didn't matter which journal we sent them to . They published our work. I always knew that if there were two journals open to our papers . In the end, we did win, because in the end all that matters is the truth. But if those two journals had also been controlled, if they'd had the same editorial boards, we wouldn't have ever done it. That was how I learned that is how industry controls information. They actively do it. They actively support people to make sure that only guidelines that benefit industry are ever published. This only exacerbates the problem. The key to treating and reversing type 2 diabetes is to cut down on net carbs, replacing them with high amounts of healthy fats and moderate amounts of protein. Noakes has researched reversal of type 2 diabetes in South Africans, coming to the same conclusion. It's just the most exciting work I can think of. That will reverse the insulin resistance, but equally important is having the ability to burn fat as your primary fuel. Paradoxically, driving your insulin level too low can result in a rise in blood sugar. The reason this can happen is because the primary function of insulin is not to drive sugar into the cell, but to suppress the production of glucose by the liver (hepatic gluconeogenesis). In situations like this, eating a piece of fruit, for example, will actually lower your blood sugar. This is what happened to me, as I went a bit too extreme in my ketogenic approach. That got me to explore this whole process, eventually concluding that continuous ketosis may not be a wise long- term approach. You actually need this cycling, where you go through a one- day- per- week fast and one or two days a week of feasting, where you eat maybe 1. Noakes is planning clinical trials with type 2 diabetics where they will be looking at these kinds of variations. Are Carbs Bad for All Athletes? It's worth noting that some athletes may not perform at their best on a ketogenic (high- fat, low- carb diet). I believe that if you're doing ultra- endurance events like marathons, the ketogenic diet is the way to go. But for high- performance spurt, interval types, it might not be your best bet. It'll help you from a health perspective, but it may not optimize your performance like it will for long- distance running. Noakes weighs in on the topic, saying. The question I want to know is, how can adding a little bit of carbohydrate make you run faster? For example, if you ingest carbohydrate during exercise, because you've got plenty of fat on board, why would you need a little bit of carbohydrate? To some extent, I think the carbohydrate effect is a drug effect, particularly during exercise. If you're taking carbohydrates, I think it's acting like a drug, because metabolically, I can't see how it would make any difference. It's really interesting. When we do these studies, we take people on high- carbohydrate diets and we put them on a high- fat diet. The performance does come down. But I wonder to what extent, as to the withdrawal of the drug effect as much as a metabolic effect . We need to remember that diabetes is one of the greatest growth industries in the world. Should Endurance Athletes Go Keto? Ketosis and Ketogenic Diets for Endurance Athletes. When it comes to weight loss and endurance performance, dietary ketosis is the strategy everyone is asking about this year. On the surface, ketosis or a ketogenic diet offers everything an endurance athlete could dream of: endless energy, freedom from bonking, and an efficient pathway to weight loss. The diet has been all over mainstream magazines, it’s the subject of several new books, and the supplement companies have already jumped in with new products and a ton of marketing dollars. So, is it time for cyclists, triathletes, and runners to go Keto? First, a refresher course on what a ketogenic diet is. To achieve dietary or nutritional ketosis you need to severely restrict carbohydrate intake (fewer than 5. CHO/day) so the body transitions to using ketones for fueling muscles and the brain. Ketones are produced from fat, which is why nutritional ketosis is so appealing to sedentary people as a weight loss solution. It’s appealing to athletes because we have a virtually unlimited reserve of fat calories to pull from but can only store 1. An athlete fueled by ketones would be theoretically “bonk- proof”, since bonking is the result of running low on blood glucose. Dietary ketosis for athletes is one of the most hotly contested subjects right now. Proponents point to the metabolic advantage of relying on fat instead of carbohydrate, and critics point out the physiological limitations of eliminating carbohydrate as a fuel for performance. You’ll find bias in both groups, either because scientists and coaches (including me) have been in the high- carbohydrate camp for many years, or because there’s a lot of money to be made by creating a market for new media and supplements around a new high- fat dietary strategy. I recognize my historical bias toward carbohydrate, but have tried to look at the science objectively. Here’s the short conclusion I’ve come to: Exogenous ketones may have promise as an additional fuel source for endurance athletes, but dietary ketosis has limitations that make it difficult to recommend to most athletes. Athletes are better served by periodizing carbohydrate availability in order to maximize training quality and performance outcomes. And here’s how I arrived at that statement: Ketosis doesn’t IMPROVE endurance performance. If you do everything right, you may be able to achieve similar performance levels during steady state endurance exercise following a high- carb (5. CHO) diet or a high- fat, low- carb (HFLC) diet (7. Fat, < 5% CHO). This means you may be able to sustain a submaximal pace equally well using either strategy. The HFLC strategy has been shown to increase the utilization of fat for energy, especially in long- term (2. Volek, 2. 01. 5). However, the oxygen cost of locomotion increases while exercising on a HFLC strategy (Burke, 2. It takes approximately 2. This isn’t necessarily a problem, since you have a large supply of energy to burn, but these findings don’t indicate an IMPROVEMENT in endurance performance. Athletes don’t go faster on HFLC, which is why we see elite athletes utilize HFLC at specific times of the year and then complete high- intensity training and competitions with high carbohydrate availability (more on that later). Ketosis is physiologically limiting. Without stored and exogenous carbohydrate during competition, you have very little fuel available for anaerobic glycolysis, the metabolic shortcut that rapidly produces energy by partially burning carbohydrate to meet elevated energy demands during short, high- intensity efforts. Ketones can be converted to acetyl- co. A and metabolized aerobically in mitochondria, but you miss out on the turbocharged boost from anaerobic glycolysis. You also miss out on the lactate produced from anaerobic glycolysis, but lactate isn’t the enemy it was once thought to be. It is partially- burned carbohydrate that gets broken down to usable energy. The reason I say you’ll have little carbohydrate available for anaerobic glycolysis instead of no carbohydrate is because an athlete in ketosis can still produce glucose in the liver via gluconeogenesis. In plain English this means athletes in ketosis have limited capacity for high- intensity efforts that rely on carbohydrate for fuel. While long cycling event may have a moderate overall intensity, there are periods of high- intensity within it. Even ultramarathons and Ironman triathlons – long considered to be low- intensity, long- duration events – feature periods of intensity above lactate threshold. For competitors, hard efforts are required to drop rivals and build winning margins. Whether you are going for the win or trying to set a PR, you will achieve your best performances in events that feature intermittent high- intensity efforts by optimizing your ability to use all fuels and by providing your body with adequate supplies of all fuels. Ketosis may prevent gastric distress. Athletes in ketosis can perform well at a steady endurance pace, and can do so for many hours while consuming far fewer calories than carbohydrate- dependent competitors. As a result, ketosis may be a good solution for athletes who consistently struggle with gastric distress during ultradistance events. During exercise lasting 9- 2. This is a problem when you are consuming large amounts of energy and fluid because food that stays in the gut too long creates the gas, bloating, and nausea that make athletes drop out of races. In fact, GI problems are the leading cause of DNFs in ultramaraton events, so the prevention of gastric distress could potentially make dietary ketosis a reasonable solution for some ultradistance athletes. For the record, CTS Coach Jason Koop, author of Training Essentials for Ultrarunning, disagrees with me on the paragraph above. He believes strongly that fat adaptation/dietary ketosis is not a good idea for ultrarunners because it is physiologically limiting and because the gut is trainable. He agrees ultraendurance athletes in ketosis might be less vulnerable to GI distress, but points out that GI distress is most often the result of poor planning and inadequate training (both physical and nutritional). In that context, ketosis is a complicated solution to a relatively simple problem, and an ultimately inferior solution in terms of maximizing physiological performance. Ketosis is very disruptive to training If carbohydrate is available it is the go- to fuel for muscles and the brain. Only in carbohydrate’s absence will the body transition to producing and using more ketone bodies for energy. This is evolutionary biology. When sugar from plants was available to our ancestors they could gorge on it, use some for energy and store the rest as fat. During times when there were no plants to eat, their carbohydrate stores ran out and they transitioned to ketosis to fuel themselves from their stored fat. To achieve ketosis voluntarily – instead of through inadequate insulin production – you have to essentially eliminate carbohydrate from your diet. Initially, you will have neither enough carbohydrate nor ketones to fuel your brain. While you are always producing ketones, it takes time (up to 2- 3 weeks) for your body to increase production to the point you are relying on them as a primary energy source. During this period, training performance will definitely suffer (and lifestyle performance may suffer as well). Your power output will be lower than normal. Your running pace will be slower than normal. Perceived exertion will go up, at all intensity levels. Recovery from training sessions will be hindered. Once you are adapted to fueling yourself primarily on ketones for day- to- day living, you still need to adapt to performing optimally as an athlete fueled by ketones. This can take months, during which time your only progress will be in fat adaptation, not aerobic development, the ability to produce power, or the ability to achieve faster paces. If you are going to try ketosis as an athlete, the best time to experiment would be a period of general aerobic endurance training. For summertime athletes in the Northern Hemisphere, this typically means fall or winter. It would be a mistake to try making this transition during a period of important, race- specific, high- intensity training. Weight loss from dietary ketosis is primarily from caloric restriction. Exercise studies of athletes who have adapted to ketosis show they burn more fat at a given exercise intensity than when they were carbohydrate- fueled, but not that they can produce more work (go faster) (Zajac, 2. When athletes get faster after adapting to ketosis, or even after a period of ketosis followed by a return to an “all fuels” strategy, weight loss is often a big contributing factor to the increase in speed. That’s not a bad outcome, but they lost weight primarily due to caloric restriction. Diets that severely restrict or eliminate food groups cause people to pay a lot of attention to all food choices. This increased focus dramatically reduces mindless eating, and the consumption of junk food, alcohol, and excess sugar. It typically leads to increased consumption of fresh, whole foods. In the case of ketosis, it leads to increased consumption of whole food sources of protein, fat, and vegetables. That’s a good outcome, too, but caloric restriction is still the primary reason people lose weight while following a ketogenic lifestyle. From a performance standpoint weight loss increases VO2 max (milliliters/kilogram/minute), improves power- to- weight ratio, and lowers the energy cost of locomotion. Even if your ability to produce power does not improve, you will go faster and be more economical when you lose weight. What doesn’t matter is whether you lost that weight through ketosis or through other ways of rebalancing caloric expenditure and caloric intake. Compliance is a major barrier to Sustaining ketosis.
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