Postexercise macronutrient oxidation: a factor dependent on postexercise macronutrient intake.
BACKGROUND
It has been widely shown that exercise increases postexercise fat oxidation and energy expenditure.


OBJECTIVE
The aim of this study was to investigate the effect of exercise on postexercise substrate oxidation and energy expenditure when the exercise-induced expenditure of energy and macronutrients oxidized is compensated by an equivalent intake immediately after exercise.


METHODS
Twenty-four-hour energy expenditure (24EE) and macronutrient oxidation of 8 young men were measured in a whole-body indirect calorimeter under the 2 following, randomly assigned conditions: 1) a control session of sedentary activities in the calorimeter for 61 h and 2) a similar session preceded by 60 min of exercise at 50% of maximal oxygen consumption. Immediately after exercising, subjects ingested a milk shake containing the same amount of energy (above resting metabolic rate) expended during exercise and with a food quotient corresponding to the mean exercise respiratory quotient. 24EE and substrate oxidation were compared between conditions on a day-to-day basis (days 1, 2, and 3) and for the 61-h observation period.


RESULTS
There was no difference in 24EE between the 2 conditions. Moreover, the composition of the postexercise fuel mix oxidized, as reflected by the respiratory quotient, was strictly the same under the 2 conditions.


CONCLUSIONS
Voluntary postexercise compensations in energy and macronutrient intakes play a major role in the ability of exercise to alter postexercise substrate utilization.
Dionne
I
I
Division of Kinesiology, Physical Activity Sciences Laboratory, Laval University, Ste-Foy, Québec, Canada.
Van Vugt
S
S
Tremblay
A
A
D000328:Adult; D004435:Eating / Q000502:physiology*; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005502:Food; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction