The Effect of Meal Timing and Caffeine Intake on Energy Expenditure, Substrate Use and Exercise Efficiency in Healthy Male Individuals |Biomedgrid

Caffeine supplementation by athletes in small to moderate doses has been shown to be an effective ergogenic aid. Studies have recognized that caffeine supplementation decreases perceived exertion, delays fatigue, and improves time trial performance. This study aims to investigate the effect of timing of caffeine and meal intake on metabolic parameters in healthy individuals. Eight active males were randomly given 3 mg/kg caffeine, followed by a standardized meal 2 hours later (C2M) and vice versa (M2C) before being required to cycle for 5 minutes at 20W, 35W, 50W, 65W, and 80W. Caffeine (C), meal + caffeine (M+C), and meal (M) only were tested separately. Mean changes in energy expenditure differed significantly for C vs M+C and M+C vs M: 3.971±0.653 vs 4.205±0.637 kcal/min; p < 0.05 and 4.205±0.637 vs 3.938±0.617; p < 0.05). Delta efficiency was significantly greater in C2M than in M2C (25.5±1.2 vs 23.6±0.8 %; p < 0.05). Mean changes in respiratory quotient were significant (C2M vs M2C, 0.012±0.004; p < 0.05, and M vs C, M+C vs C, and M+C vs M, 0.062±0.008 (p < 0.001), -0.024±0.009 (p < 0.01), -0.038±0.015 (p < 0.01). The timing of meals and caffeine intake resulted in metabolic alterations in a non-dependent manner. This makes it difficult to explain the relationship between muscular efficiency and substrate use; however, it does require more research to target exercise performance, as well as body composition regulation.