Exogenous Ketone Supplementation and Keto-Adaptation for Endurance Performance: Disentangling the Effects of Two Distinct Metabolic States

This review distinguishes exogenous ketone supplementation, which achieves nutritional ketosis (blood ketone bodies above 0.5 mM) within minutes, from keto-adaptation, which follows chronic ketogenic diet adherence of more than 3 weeks. It states that the two are distinct metabolic states with different effects on substrate availability and metabolism during exercise. It concludes that inducing nutritional ketosis is rarely ergogenic irrespective of origin and can impair endurance performance, though both approaches may have utility for select events and individuals.