Oral ketone monoester ingestion reduces circulating blood glucose, exogenous carbohydrate oxidation and oxidation efficiency in trained male cyclists when fed 120 g of CHO per hour during exercise

ABSTRACT:

We examined the effects of ketone monoester (KME) and carbohydrate (CHO) co-ingestion on exogenous CHO oxidation, metabolomic responses and exercise capacity. In a randomised repeated-measures design (after a 36 h CHO loading protocol and pre-exercise meal of 12 and 2 g.kg-1, respectively), eight trained male cyclists ingested 0 g.h-1 (PLA), 120 g.h-1 CHO (CHO) or 75 g ketone monoester + 120 g.h-1 CHO (CHO + KME) during 3 h of cycling at 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<0.05) such that CHO > CHO + KME > PLA (4.90 ± 0.30, 4.36 ± 0.23, 3.68 ± 0.39 mmol.L-1, respectively).  Mean exogenous CHO oxidation (1.35 ± 0.15 vs 1.50 ± 0.16 g.min-1, P<0.01) and oxidation efficiency was lower in CHO + KME (67 ± 7 %) compared to CHO (75 ± 6%, P <0.01). Exercise capacity was greater (P<0.01) in CHO (349 ± 189 s) and CHO + KME (319 ± 225 s) compared to PLA (75 ± 105 s), though no differences were evident between CHO and CHO+KME (P > 0.99). Untargeted metabolomics also provide novel data by demonstrating that ketone monoester ingestion increased abundance of metabolites associated with carbohydrate metabolism (Glucaric acid) and protein turnover (3-Methylhistidine).  In conditions considered representative of high CHO availability during exercise, we conclude that ketone monoester ingestion reduces blood glucose concentrations, exogenous CHO oxidation and oxidation efficiency when compared to CHO alone.  

INSTRUMENT(S): Nuclear Magnetic Resonance (NMR) -

PROVIDER: MTBLS6260 | MetaboLights | 2026-04-22

REPOSITORIES: MetaboLights