What question did this study set out to answer?

This research investigates how ketone monoester affects carbohydrate metabolism and exercise performance in trained cyclists.

April 12, 2026

Ketone monoester reduces blood glucose, exogenous CHO oxidation and oxidation efficiency in trained male cyclists when fed 120 g/h of CHO during exercise

Key Points

This research investigates how ketone monoester affects carbohydrate metabolism and exercise performance in trained cyclists.
Randomized crossover design with eight trained male cyclists.
Participants ingested 0 g.h -1 (PLA), 120 g.h -1 CHO, or 120 g.h -1 CHO + 75 g ketone monoester during cycling.
Blood glucose and exogenous carbohydrate oxidation were measured during exercise.
Mean blood glucose was highest in CHO (4.9 mmol.L -1) compared to CHO + KME (4.4 mmol.L -1) and PLA (3.7 mmol.L -1).
Exogenous carbohydrate oxidation was lower in CHO + KME (1.35 g.min -1) than CHO (1.50 g.min -1).
Exercise capacity was significantly greater in CHO than PLA (349 s vs 75 s), while CHO + KME was also higher than PLA (319 s).

Abstract

We examined the effects of ketone monoester (KME) and carbohydrate (CHO) co-ingestion on exogenous CHO oxidation (via U- 13 C enriched glucose-fructose drinks), metabolomic responses and exercise capacity. In a randomised crossover design (after 36 h of CHO loading and pre-exercise meal of 12 and 2 g.kg -1 , respectively), eight trained male cyclists (V̇O 2max ; 66 ± 7 mL.kg -1 .min -1 ) ingested 0 g.h -1 (PLA), 120 g.h -1 CHO (CHO), or 120 g.h -1 CHO + 75 g ketone monoester (CHO + KME) during 3 h of cycling at power outputs corresponding to 95 % of lactate threshold (LT) followed by exercise to exhaustion at 150 % LT . Mean blood glucose concentrations during exercise were different between all pairwise comparisons (P CHO + KME > PLA (4.9 ± 0.3, 4.4 ± 0.2, 3.7 ± 0.4 mmol.L -1 , respectively). Mean exogenous CHO oxidation (1.35 ± 0.15 vs 1.50 ± 0.16 g.min -1 , P0.05). Ketone monoester ingestion increased abundance of metabolites associated with carbohydrate metabolism (Glucaric acid) and protein turnover (3-Methylhistidine). We conclude that ketone monoester ingestion does not enhance exercise capacity and reduces blood glucose concentrations, exogenous CHO oxidation and oxidation efficiency when compared to CHO alone.

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