The effect of a ketone monoester drink on blood glucose and substrate oxidation in adults with metabolic syndrome and matched controls

This study aimed to evaluate the acute metabolic effects of oral ketone esters (KE) in individuals with and without metabolic syndrome (MetS) on resting energy expenditure (REE), respiratory exchange ratio (RER), and substrate utilization using respiratory gas exchange. Eight participants with MetS and 8 without MetS matched for age, race, and ethnicity completed a randomized, single-blind, placebo-controlled crossover study. Participants underwent a cardiometabolic screening to confirm MetS, followed by two experimental trials. Respiratory gases were measured for 15 min at baseline and 45 and 105 min after a randomly assigned KE or placebo beverage. Following KE ingestion, RER, carbohydrate oxidation (CarbOx), and blood ketones increased significantly, while blood glucose and fat oxidation (FatOx) decreased significantly, irrespective of group. The MetS group showed higher βHB responses to the KE condition than their matched controls, but blood glucose reductions were comparable between groups. Substrate oxidation was similar between the MetS and matched control groups across conditions. Irrespective of MetS status, oral KE acutely increase CarbOx and RER, while concurrently reducing FatOx, without altering REE, suggesting that substrate utilization shifts toward greater CarbOx following KE. Exogenous ketosis may be a promising nonpharmacological strategy to improve metabolic function in individuals with or at risk for MetS.