Can runners go keto?

This question is about Nutrition and Running

Natalie Rizzo, MS, RD, Freelance Writer

The keto diet is not advisable for runners, as it may hinder overall performance



The keto diet is a high fat, low carbohydrate diet that consists of less than 50 grams of carbs per day. Carbohydrate is the primary fuel source for working muscles, and severe restriction appears to have a negative impact on endurance performance



The keto diet has two big downsides for runners: limited glucose availability and increased oxygen demands. Although fat burning increases following a keto diet, endurance capacity in keto-adapted athletes still appears to be limited by glucose availability [


]. A keto-adapted runner will simply have less glucose available to fuel a long run than a carbohydrate-fed competitor, and research to date suggests that this impairs performance, even if carbohydrate is temporarily restored pre-run [



Despite increased fat burning, endurance capacity in keto-adapted athletes still appears to be limited by glucose availability [


]. Keto may not also offer bigger performance benefits due to the fact that ATP (energy) production from fatty acids requires more oxygen than glucose does [




]. These greater oxygen demands decrease efficiency during exercise and thus limit the potential performance benefits for runners following a strict ketogenic diet.

an assortment of keto-friendly foods

  1. Kerksick, C.M., Wilborn, C.D., Roberts, M.D. et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr 15, 38 (2018).

  2. Burke, L. M., Sharma, A. P., Heikura, I. A., Forbes, S. F., Holloway, M., McKay, A., Bone, J. L., Leckey, J. J., Welvaert, M., & Ross, M. L. (2020). Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible. PloS one, 15(6), e0234027.

  3. McSwiney, F. T., Doyle, L., Plews, D. J., & Zinn, C. (2019). Impact Of Ketogenic Diet On Athletes: Current Insights. Open access journal of sports medicine, 10, 171–183.