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Fast Talk, ep. 46: Inside ketogenic and high-fat diets

Chris Case /

The VeloNews Fast Talk podcast is your source for the best training advice and most compelling insight on what it takes to become a better cyclist. Listen in as VeloNews managing editor Chris Case and our resident physiologist and coach, Trevor Connor, discuss a range of topics, including training, physiology, technology, nutrition, and more.

IF WE HAD TO SUMMARIZE sports nutrition in one word it would probably be … controversial. Or maybe just confusing. Endurance sports guidelines tell us we need to pack in the carbohydrates. Then we hear about Team Sky and other prominent athletes resorting to a nearly carbohydrate-free diet. So which one is best, and frankly do we even need to be eating the same way a grand tour rider eats?

One thing that’s certain is that in the world of nutrition, “keto” has become a buzzword — and not only in the sports world. Terms like “ketogenic diet” have become some of the most searched dietary terms on Google. It’s even made its way to the most important forum of public opinion — the Saturday morning group ride conversation.

But what is a ketogenic diet? And in a sport where high-carb pasta dinners and simple sugar sports drinks have been the norm for decades, why are we even talking about a very low-carbohydrate, high-fat diet? Today we’ll delve into that subject.

First, what is meant by a “ketogenic diet” and what are ketones? Evolution felt there was an important reason we evolved to use them, so what exactly do they do?

We’ll discuss the difference between a ketogenic diet and a high-fat/low-carbohydrate diet, and why the latter may be the more important one to discuss.

Are there potential health benefits, outside of performance, of trying a ketogenic diet? We’ll take a look.

What does the current research say about the ketogenic diet and sports performance? There are studies concluding contradictory things, and researchers have strong opinions on both sides.

Finally, if you’d like to try a ketogenic or high-fat diet, we’ll talk about the best ways to go about doing it, and also discuss why a less extreme high-fat/low carbohydrate diet may be better.

Our primary guest is a researcher who has become one of the most well-known faces of the high-fat movement — Dr. Timothy Noakes. Dr. Noakes has been at the center of endurance science and sports nutrition research for decades. He wrote, among other books, the very popular “Lore of Running” in the 1980s.

But while training as a high-level marathon runner, Noakes became diabetic, which set him on the path to look for alternative solutions to the accepted high-carbohydrate dietary approach of the ’80s and ’90s.

In episode 23, we interviewed Dr. John Hawley, who along with his wife Dr. Louise Burke, is another top name in the world of endurance nutrition research. They are both strong proponents of the use of carbohydrates for sports performance. However, if you look back at both Noake’s and Hawley’s early research, you’ll notice something interesting — it’s the same. Noakes, Burke, and Hawley did a lot of their early research on both high-carbohydrate and low-carbohydrate diets together.

And yet, the same research led them to very different conclusions. In episode 23, Hawley made a strong case for why we need carbohydrates. In this episode, Noakes will take on a lot of that same research and explain why his interpretation is fundamentally different. So grab your seat, because it’s going to be a fun ride.

Along with Dr. Noakes, we also talked with professional rider Joe Dombrowski of EF Education First-Drapac, who expressed the skepticism shared by other riders in the pro peloton.

We also hear from Sepp Kuss of LottoNL-Jumbo. While he hasn’t tried a ketogenic diet himself, Sepp talked about a team training strategy of training high and training low — that is, starting some rides packed with carbohydrates, while doing other rides on no carbohydrates.

So, let’s chew the fat, and make you fast!

Fast Talk is available on all your favorite podcast services, including iTunesStitcherGoogle Play, and Soundcloud. If you enjoy the podcast, please take a moment to rate and comment on iTunes after listening. Also, check out the VeloNews Cycling Podcast, our weekly discussion of the sport’s hottest topics, trends, and controversies.

References

Bartlett, J. D., Hawley, J. A., & Morton, J. P. (2015). Carbohydrate availability and exercise training adaptation: too much of a good thing? Eur J Sport Sci, 15(1), 3-12.

Burke, L. M. (2015). Re-Examining High-Fat Diets for Sports Performance: Did We Call the ‘Nail in the Coffin’ Too Soon? Sports Med, 45 Suppl 1, S33-49.

Burke, L. M., Ross, M. L., Garvican-Lewis, L. A., Welvaert, M., Heikura, I. A., Forbes, S. G., et al. (2017). Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers. J Physiol, 595(9), 2785-2807.

Cox, P. J., & Clarke, K. (2014). Acute nutritional ketosis: implications for exercise performance and metabolism. Extrem Physiol Med, 3, 17.

Havemann, L., West, S. J., Goedecke, J. H., Macdonald, I. A., St Clair Gibson, A., Noakes, T. D., et al. (2006). Fat adaptation followed by carbohydrate loading compromises high-intensity sprint performance. J Appl Physiol (1985), 100(1), 194-202.

Hawley, J. A., & Leckey, J. J. (2015). Carbohydrate Dependence During Prolonged, Intense Endurance Exercise. Sports Med, 45 Suppl 1, S5-12.

Hetlelid, K. J., Plews, D. J., Herold, E., Laursen, P. B., & Seiler, S. (2015). Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners. BMJ Open Sport Exerc Med, 1(1), e000047.

Kearns, C. E., Glantz, S. A., & Schmidt, L. A. (2015). Sugar industry influence on the scientific agenda of the National Institute of Dental Research’s 1971 National Caries Program: a historical analysis of internal documents. PLoS Med, 12(3), e1001798.

Kearns, C. E., Schmidt, L. A., & Glantz, S. A. (2016). Sugar Industry and Coronary Heart Disease Research: A Historical Analysis of Internal Industry Documents. JAMA Intern Med, 176(11), 1680-1685.

Phinney, S. D., Bistrian, B. R., Evans, W. J., Gervino, E., & Blackburn, G. L. (1983). The human metabolic response to chronic ketosis without caloric restriction: preservation of submaximal exercise capability with reduced carbohydrate oxidation. Metabolism, 32(8), 769-776.

Phinney, S. D., Bistrian, B. R., Wolfe, R. R., & Blackburn, G. L. (1983). The human metabolic response to chronic ketosis without caloric restriction: physical and biochemical adaptation. Metabolism, 32(8), 757-768.

Pinckaers, P. J., Churchward-Venne, T. A., Bailey, D., & van Loon, L. J. (2017). Ketone Bodies and Exercise Performance: The Next Magic Bullet or Merely Hype? Sports Med, 47(3), 383-391.

Volek, J. S., Noakes, T., & Phinney, S. D. (2015). Rethinking fat as a fuel for endurance exercise. Eur J Sport Sci, 15(1), 13-20.

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