Effect of Exogenous Ketosis During Ultra-endurance Exercise

Inclusion Criteria: * Males between 18 and 55 years old * Recreational or competitive runner having performed an ultramarathon (\>42km) during the last 2 years * Good health status confirmed by a medical screening * Body Mass Index (BMI) between 18 and 25 Exclusion Criteria: * Any kind of injury/pathology that is a contra-indication to perform ultra-endurance exercise * Intake of any medication or nutritional supplement that is known to affect exercise performance * Intake of analgesics, anti-inflammatory agents, or supplementary anti-oxidants, from 2 weeks prior to the start of the study. * Blood donation within 3 months prior to the start of the study * Smoking * More than 3 alcoholic beverages per day * Current participation in another research trial * Any other argument to believe that the subject is unlikely to successfully complete the full study protocol * Adherence to a high-fat, low-carbohydrate ketogenic diet (less than 20% of energy intake derived from carbohydrates)