|Ketogenic dieting will help to preserve performance, but in contrast to what the hype on the Internet says, it won't help already lean taekwondo athletes to improve their body composition.|
If you look at the outcomes of a recent study from the Jungwon University and the Seoul Women’s University in Korea it would appear as if Volek, Noakes and Phinney were actually up to something.
The purpose of said study was to investigate the effects of the weight loss through 3 weeks of ketogenic diet on performance-related physical fitness and inflammatory cytokines in Taekwondo athletes.
In contrast to what you'd expect based on the hype around ketogenic dieting in the bodybuilding and fitness community, the ketogenic diet that contained 55.0%, 40.7%, and 4.3% of the daily energy intake in form of fat, protein and carbohydrates respectively did not experience greater improvements in body composition than their peers on a 30%, 30%, and 40% fat, protein, carbohydrate diet.
"The subjects selected for this research were 20 Taekwondo athletes of the high schools who participated in a summer camp training program. The subjects were randomly assigned to 2 groups, 10 subjects to each group: the ketogenic diet (KD) group and the non-ketogenic diet (NKD) group. Body composition, performance-related physical fitness factors (2,000 m sprint, Wingate test, grip force, back muscle strength, sit-up, 100 m sprint, standing broad jump, single leg standing) and cytokines (Iinterleukin-6, Interferon-γ, tumor necrosis factor-α) were analyzed before and after 3 weeks of ketogenic diet." (Rhyu. 2014)
Figure 1: Macronutrient composition of the two 25% energy reduced test diets (Rhyu. 2014)
If you want to do a keto diet, say goodbuy to tons of protein: What may not be obvious to all of you is the fact that the diet at hand is low in carbs, but not high enough in fat to be truly ketogenic. With 40% protein you are not going to go into ketosis. That's simply too much protein to be converted to glucose in the liver - specifically if you get some of the protein from fast digesting protein sources like whey, which will spike the blood amino acid levels and kickstart hepatic gluconeogenesis. Unfortunately, the study does not list the absolute protein intake, but if we assume a baseline intake of 2800kcal per day for the subjects, they would have consumed 210g of protein per day - that's 3.2g/kg for these lean guys - and still lost muscle.What is particularly interesting in this context is that the diet is as Jacob Wilson pointed out in a comment on my facebook page, probably not even "ketogenic". As he says, they found in their studies that "subjects generally need to have fat near 70 % or above to reach nutritional ketosis". The diet in the study at hand is thus too high in protein - just like the diets of 90%+ of the people in the fitness world who believe they were following a ketogenic diet, when they are in fact only eating a high protein diet with some fat and low carbohydrates in it.
- Rhyu, Hyun-seung, and Su-Youn Cho. "The effect of weight loss by ketogenic diet on the body composition, performance-related physical fitness factors and cytokines of Taekwondo athletes." Journal of Exercise Rehabilitation 10.5 (2014): 326-331.
- Volek, Jeff S., Timothy Noakes, and Stephen D. Phinney. "Rethinking fat as a fuel for endurance exercise." European journal of sport science ahead-of-print (2014): 1-8.