Lipid metabolism links nutrient-exercise timing to insulin sensitivity in men classified as overweight or obese

Abstract

AbstractContextPre-exercise nutrient availability alters acute metabolic responses to exercise, which could modulate training responsiveness. We hypothesised that in men with overweight/obesity, acute exercise beforeversusafter nutrient ingestion would increase whole-body and intramuscular lipid utilization, translating into greater increases in oral glucose insulin sensitivity over 6-weeks of training.Design and ParticipantsWe showed in men with overweight/obesity (mean±SD for BMI: 30.2±3.5 kg×m-2for acute, crossover study, 30.9±4.5 kg×m-2for randomized, controlled, training study) a single exercise bout beforeversusafter nutrient provision increased lipid utilisation at the whole-body level, but also in both type I (p<0.01) and type II muscle fibres (p=0.02). We then used a 6-week training intervention to show sustained, 2-fold increases in lipid utilisation with exercise beforeversusafter nutrient provision (p<0.01).Main Outcome MeasuresPostprandial glycemia was not differentially affected by exercise training beforevsafter nutrient provision (p>0.05), yet plasma was reduced with exercise training before, but not after nutrient provision (p=0.03), resulting in increased oral glucose insulin sensitivity when training was performed beforeversusafter nutrient provision (25±38vs−21±32 mL×min-1×m-2;p=0.01) and this was associated with increased lipid utilisation during exercise (r=0.50,p=0.02). Regular exercise prior to nutrient provision augmented remodelling of skeletal muscle phospholipids and protein content of the glucose transport protein GLUT4 (p<0.05).ConclusionsExperiments investigating exercise training and metabolic health should consider nutrient-exercise timing, and exercise performed beforeversusafter nutrient intake (i.e., in the fasted state) may exert beneficial effects on lipid utilisation and reduce postprandial insulinemia.PrécisExercise in the fasted-versusfed-state increased intramuscular and whole-body lipid use, translating into increased muscle adaptation and insulin sensitivity when regularly performed over 6 weeks.