Dataset for "Lipid metabolism links nutrient-exercise timing to insulin sensitivity in overweight men"

The aim of the present work was to assess the acute and chronic effects of manipulating nutrient-exercise timing on lipid metabolism, skeletal muscle adaptation, and oral glucose insulin sensitivity in overweight and obese men. This project comprised two experiments. We first assessed the acute metabolic and mRNA responses to manipulating nutrient-exercise timing (Acute Study), followed by a 6-week randomized controlled trial to assess the longer-term adaptations in response to nutrient-exercise timing (Training Study). We showed that in overweight/obese, but otherwise healthy men (mean±SD for age: 30 ± 10 years for acute study, 35 ± 9 years for training study and BMI: 30.2±3.5 kg/m-2 for acute study, 30.9±4.5 kg/m-2 for training study) a single exercise bout before versus after nutrient provision increased lipid utilization at the whole-body level, but also in both type I (p<0.01) and type II muscle fibers (p=0.02). We then used a 6-week intervention to show sustained, 2-fold increases in lipid utilization with exercise training before versus after nutrient provision (p<0.01). An oral glucose-derived estimate of peripheral insulin sensitivity (OGIS index) increased when training was performed before versus after nutrient provision (25±38 vs -21±32 mL/min/m-2; p=0.01) and this was associated with increased lipid utilization during exercise (r=0.50, p=0.02). Regular exercise prior to nutrient provision augmented remodelling of skeletal muscle phospholipids and muscle expression of the glucose transport protein GLUT4 (p<0.05). These responses were observed despite similar changes in body mass, waist-to-hip ratio, and oxidative capacity. Therefore: 1) experiments investigating exercise training and metabolic health need to control for nutrient-exercise timing; 2) exercise performed before versus after nutrient intake may exert beneficial effects on lipid utilization and oral glucose insulin sensitivity.