Nutritional Ketosis Alters Fuel Preference and Thereby Endurance Performance in Athletes.
Level 2 - randomized trial
Randomized controlled trials across five sub-studies in humans
PubMed 27475046 · doi:10.1016/j.cmet.2016.07.010
What was done
Across five separate studies involving a total of 39 high-performance athletes, researchers investigated the metabolic and endurance effects of acute nutritional ketosis induced by an exogenous ketone ester supplement without caloric or carbohydrate restriction.
What was found
The abstract reports no numerical values, effect sizes, or statistical confidence intervals. Directionally, ketone ester ingestion improved physical endurance by altering oxidative fuel selection. 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 in the presence of normal muscle glycogen, co-ingested carbohydrate, and elevated insulin.
Why it matters
This study demonstrates that exogenous ketone supplementation can acutely alter muscle substrate competition and enhance endurance performance without requiring chronic carbohydrate deprivation.
Limits
The abstract provides no numerical data, baseline metrics, or statistical significance values. The total sample size is small (39 athletes across five separate sub-studies), limited to elite performers, and does not evaluate chronic adaptation, gastrointestinal tolerance, or non-athletic populations.
Cited by
- supports Research by Kieran Clarke at Oxford demonstrated performance benefits of ketone ester supplementation in elite cyclists and endurance athletes.