The claimEvidence C · limited
Endurance training requires a ketogenic diet
The evidence
Keto is a therapeutic diet, not the endurance default. High-intensity anaerobic performance usually drops once glycogen is depleted, and long-term cardiovascular effects are unclear.
The mechanism, in brief
The ketogenic diet is very low carb (typically <50g/day), high fat (70-80% kcal), moderate protein. Cut the carbohydrate and the liver breaks fatty acids into ketone bodies (β-hydroxybutyrate, acetoacetate) so the brain and other tissues burn those instead. This isn't a lifestyle diet — it's a therapeutic diet.
Sources (3)
- Ludwig, D. S. (2020). The ketogenic diet: evidence for optimism but high-quality research needed. Journal of Nutrition, 150(6), 1354-1359. Well-formulated ketogenic diets appear more effective than low-fat diets for obesity and T2D short-term; chronic ketosis may have unique metabolic benefits; high-quality long-term RCTs are needed.
- Crosby, L., Davis, B., Joshi, S., Jardine, M., Paul, J., Neola, M., et al. (2021). Ketogenic diets and chronic disease: weighing the benefits against the risks. Frontiers in Nutrition, 8, 702802. Ketogenic diets may provide short-term improvement for some conditions but typically increase saturated fat intake, decrease protective foods; LDL may rise; long-term safety data are lacking; for most individuals risks may outweigh benefits.
- Gardner, C. D., Trepanowski, J. F., Del Gobbo, L. C., Hauser, M. E., Rigdon, J., Ioannidis, J. P. A., et al. (2018). Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion: the DIETFITS randomized clinical trial. JAMA, 319(7), 667-679. 609 adults, 12 months; no significant weight-loss difference between healthy low-fat and healthy low-carbohydrate diets, and neither genotype pattern nor baseline insulin secretion predicted which diet worked better.