Pre-exercise meal on oxidation of energy substrates during maximal exercise test in non-trained individuals

Abstract

ABSTRACT Objective: This study aimed to compare the influence of a high carbohydrate meal versus high-fat meal on the oxidation of substrates during an exercise incremental test. Materials and methods: Ten untrained male subjects underwent two days of the protocol. Randomly, they received a high carbohydrate meal or a high-fat meal, receiving the other one in the next protocol. On both days, they performed an incremental treadmill test, with heart rate and maximal oxygen consumption to estimate the oxidation of substrates. Results: The high-fat meal showed an increase in the absolute amount of oxidized fat along with the incremental test (P < 0.05; effect size = 0.9528), and a reduction in the respiratory exchange ratio at low intensities (P < 0.05; effect size = 0.7765). Conclusions: The meals presented no difference when compared to maximum oxidation point of substrates, the oxidation rate of substrates over time, and heart rate. A pre-test high-fat meal in untrained individuals was shown to be a modulating factor of total oxidized fats throughout the exercise, although it did not exert a significant effect on the rate of this oxidation over time.

Keywords

• Dietary fats
• dietary carbohydrates
• calorimetry
• energy metabolism
• exercise