Published: Cell Metabolism 2016
Link: https://pubmed.ncbi.nlm.nih.gov/27475046/

Background: During human evolution, ketones served to power the brain and muscles during periods of starvation or when carbohydrates were scare. The advent of our exogenous ketone ester, which produces the bioidentical ketone molecule to that produced by the human liver, made it possible to test the exercise performance effects of entering ketosis without the need for starvation or high-fat ketogenic diet.

Results: In a series of five separate studies on 39 highly trained athletes, supplementation with ketone ester shifted metabolism to a state more favorable for endurance performance, including an increase in the rate of intramuscular fat burned and a preservation of muscle glycogen. These adaptations, caused by the ketone ester, translated into a significant improvement on an endurance cycling test.