Association of metabolic flexibility indexes after an oral glucose tolerance test with cardiometabolic risk factors

Background & aims Metabolic flexibility (MetF) is considered a metabolic health biomarker, as excess body weight is associated with lower MetF. We aimed to identify whether MetF indexes were associated with cardiometabolic risk factors before and after adjustment for body size-related factors (body weight, fat-free mass, and resting metabolic rate). Methods We studied 51 participants (55% women; 33.6 ± 8.7 years; 26.3 ± 3.8 kg/m²) who consumed a 75-g glucose load. We measured gas exchange before (fasting) and for 3 h after glucose ingestion. MetF indexes were assessed, including the change after each hour and the 3-hour incremental area under the curve (iAUC) in respiratory exchange ratio (RER). These indexes were then related to cardiometabolic risk factors before and after adjusting for body size-related factors. Results MetF indexes correlated with each other ( r ≥ 0.51; P