Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes

Across five separate studies of 39 high-performance athletes, the authors used a ketone ester-based form of nutrition to induce ketosis without caloric or carbohydrate restriction and examined its effect on fuel use and endurance. Ketosis decreased muscle glycolysis and plasma lactate concentrations while providing an alternative substrate for oxidative phosphorylation. It also increased intramuscular triacylglycerol oxidation during exercise, even with normal muscle glycogen, co-ingested carbohydrate and elevated insulin.