OBJECTIVE: The present study assessed, on 5 consecutive days, the effect of consuming meals with different glycemic indices on energy expenditure, energy substrate oxidation and excessive oxygen consumption after exercise. METHODS: A total of 15 well trained men aged M=24.4, SD=3.70 years with a mean body mass index of M=21.97, SD=1.46 kg/m² and maximum oxygen uptake (VO2max) of M=70.00, SD= 5.32 mL(kg.min)-1 participated in the study. After the meal, the participants remained 90 minutes in the indirect calorimeter Deltatrac® for assessment of the metabolic parameters. Next, they exercised at 85-95% of their maximum heart rate in three bouts of 10 minutes. The metabolic parameters were reassessed within the 60 minutes following the exercise. RESULTS: The study treatments did not affect energy expenditure, excessive oxygen consumption or fat oxidation after exercise. However, the rate of fat oxidation in the 90 minutes that followed the meal was higher in those who consumed the high-glycemic index meal than in those who consumed the low-glycemic index meal. Moreover, the postprandial fat oxidation rate was lower than that observed after the exercise. CONCLUSION: These results suggest that, while the consumption of low-glycemic index meals may not have beneficial effects, exercise can promote greater fat oxidation and, consequently, reduce body fat.
Oxygen consumption; Exercise; Glycemic index; Energy metabolisme; Substrate