Research Highlight :Keto-Adaptation Enhances Exercise Performance and Body Composition Responses to Training in Endurance Athletes

Endurance performance is often limited by how much glucose is available during exercise, giving rise to the vast amount of carbohydrate-based sports supplements on the market. But what if you had access to virtually an unlimited alternative fuel source, and it didn’t require frequent feeding throughout prolonged exercise?

Nutritional ketosis may partially relieve an athlete’s dependence on glucose, however it may require a period of “adaptation” to really get the body used to using fat and ketones for fuel. The idea is that, keto-adapted athletes have access to a MUCH larger fuel reserve given that humans can only store ~2000 calories as glycogen compared to ~40,000 calories stored in fat.

In a 2017 study by McSwiney et al., male endurance trained athletes were maintained for 12-weeks on either a high-carb or ketogenic diet to investigate whether the diets produced differences in performance (endurance, strength, and HIIT) and body composition. Following the 12-weeks, compared to the high-carb group, the keto-adapted athletes:

Improved body composition - reduced total body mass and fat mass while maintaining lean body mass

Increased peak power during a 6-second sprint and HIIT

Maintained endurance performance during 100km time trial (cycling) although was not significantly different to high-carb group

Overall, 12-weeks on a ketogenic diet did not decrease performance, rather it improved many aspects of performance. The authors note the importance of diet composition (ie. to truly induce ketosis) and the length of adaptation (at least 4-6 weeks to see performance improvements).

To learn more about this study, click here: https://www.ncbi.nlm.nih.gov/pubmed/29108901