Analysis of whole-body nutrient oxidation dynamics and its relationship to physical fitness and self-reported macronutrient intake in professional football players.

Abstract

This study assessed the correlation between fat and carbohydrate oxidation dynamics in professional football players (body fat: 15.5 ± 1.0%; VO2max: 56.5 ± 1.2 ml kg−1 min−1), exploring its association to physical fitness and self-reported macronutrient intake. A graded exercise test was performed on a treadmill for the assessment of nutrient oxidation rates via indirect calorimetry. Then fat oxidation kinetics was fitted through the sine mathematical model for determining maximal fat oxidation (MFO) and its corresponding exercise intensity (FATmax). The symmetry, dilatation and translation of the curve were also computed. Carbohydrate oxidation kinetics was modelled through a third-degree polynomial regression and its area under the curve (AUCcarbs) was computed for each individual. Body composition was examined through bioelectrical impedance and macronutrient intake was determined by the 24 h recall method. The AUCcarbs was inversely related to the FATmax (r = −0.69, p < 0.01), the exercise intensity at which fat oxidation became negligible (r = −0.87, p < 0.01), and the dilatation of the fat oxidation kinetics (r = −0.51, p < 0.05). Furthermore, only body fat percentage turned to be positively correlated to MFO (r = 0.49, p < 0.05), whereas cardiorespiratory fitness was inversely related to the dilatation of the fat oxidation curve (r = −0.51, p < 0.05). The self-reported macronutrient intake was not related to fuel oxidation during the exercise. In conclusion, nutrient oxidation is associated with physical fitness but not self-reported macronutrient intake in professional football players. The impact of long-term nutritional interventions on footballer’s metabolism warrants further investigation.