We determined the effect of consuming low-glycemic index (LGI) skim milk compared to a high-glycemic index (HGI) sports drink following evening exercise on fat oxidation and blood lipids after a subsequent high-energy breakfast. We hypothesized that postexercise skim milk consumption, compared to sports drink, would increase fat oxidation and lower harmful blood lipid and glucose concentrations after a next-day high-energy breakfast. In this randomized counterbalanced crossover trial, 20 overweight-obese participants (body mass index ≥ 25 kg/m) underwent 4 conditions: 90-minute exercise (50% Vo) followed by sports drink (EX-HGI), exercise followed by isoenergetic skim milk (EX-LGI), exercise followed by water (Exercise), and a control condition (Control). The amount of the sports drink or milk consumed postexercise was based on the energy used during exercise plus 10%. Blood lipids, glucose, and fat oxidation were assessed before and for 6 hours after a high-energy breakfast the next morning. Fat oxidation was highest for EX-LGI (6.7 ± 2.7 g/h) and lowest for EX-HGI (6.0 ± 1.8 g/h) (condition main effect; P = .042). Triglyceride concentration and total area under the curve were higher with EX-HGI than Exercise (1.7 ± 1.6 vs 1.3 ± 1.0 mmol/L, P = .037, and 11.7 ± 9.4 vs 8.6 ± 6.0 mmol L h, P = .005, respectively). Glucose concentration was lower with EX-LGI than EX-HGI (4.1 ± 1.1 vs 4.4 ± 1.1 mmol/L, P = .027). Homeostatic model assessment of insulin resistance was higher with EX-HGI than Control (2.32 ± 1.15 vs 1.86 ± 0.97, P = .005). In conclusion, evening postexercise skim milk consumption, compared with a high-GI sports drink, significantly reduced blood glucose and possibly increased fat oxidation after a high-energy breakfast the next morning.
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