Ketone Monoester Followed by Carbohydrate Ingestion after Glycogen-Lowering Exercise Does Not Improve Subsequent Endurance Cycle Time Trial Performance

Nine recreationally active men completed glycogen-lowering exercise, then 4 hours of recovery, then a 20 km and a 5 km best-effort cycling time trial. During the first 2 hours of recovery they ingested either ketone monoester (25 g) followed by carbohydrate at 1.2 g/kg/h, or an iso-energetic dextrose placebo followed by the same carbohydrate. The ketone condition gave higher blood beta-hydroxybutyrate, lower blood glucose at 30 and 60 minutes and higher blood insulin at 2 hours (all p < 0.05). There were no differences in power output or time for either time trial.