The effect of short-term different diet modifications on postexercise metabolism following a sprint interval exercise

A single sprint interval training (SIT) session is known to have positive effects on fat metabolism by increasing postexercise oxygen consumption (V̇O2) and fat oxidation. A short-term high-fat diet intervention has positive effects on fat oxidation pre- and postsubmaximal exercise sessions. However, there is no study on the effects of the combination of diet and a SIT session on fat oxidation. The study aimed to investigate the effect of different short-term diet modifications on fat oxidation following a SIT session.

Nine healthy active males (24.3±5.27 years) participated in this investigation. Following isocaloric normal (NOR), high carbohydrate (CHO), and high fat (FAT) diet interventions with a weekly interval, participants performed an SIT session (6 repeats × Wingate all-out sprints with 4.5 minutes of rest in-between bouts). V̇O2 and V̇CO2 were measured by a gas analyzer throughout a 2-hour recovery period.

There was no significant time × session interaction for fat oxidation, V̇O2, total energy expenditure, and respiratory exchange ratio. The resting fat oxidation (g.min^-1) was statistically greater in the FAT diet (0.12±0.04) than in the CHO (0.08±0.02, P=0.012) and NOR (0.08±0.02, P=0.009) diets. Only a 2-hour postexercise fat oxidation (g.min^-1) (0.22±0.05) was statistically higher for the FAT diet compared to the CHO diet (0.15±0.05; P=0.006).

While the study showed significant differences in fat oxidation between diets, the magnitude of the difference was so small (~0.04 g/min) that it may not have a truly effective 'real world' implication for burning extra calories.