Post-exercise dietary macronutrient composition modulates components of energy balance in young, physically active adults

The effectiveness of exercise to reduce body mass is typically modest, partially due to energy compensation responses which may be linked to energy substrate availability around exercise. The present study aimed to investigate the effect of manipulating post-exercise energy substrate availability (high carbohydrate/low fat [HCLF] or low carbohydrate/high fat [LCHF] energy replacement) on energy balance components in the short-term (i.e., appetite, energy intake (EI) and energy expenditure (EE)).

Methods: Appetite, EI, activity- and total- EE were measured in twelve healthy, young (21.0 ± 2.3 years) physically active participants (10 men, 2 women) on two occasions across 4 days after a 75-min run and an isocaloric energy replacement drink (HCLF and LCHF). Appetite was measured daily by visual analogue scales, EI was calculated by subtracting the energy content of food leftovers from a provided food package, activity- and total- EE determined by heart-rate accelerometery.

Results: Composite appetite ratings between days were lower in HCLF (62.4 ± 12) compared to LCHF (68.3 ± 8.9 mm; p = 0.048). No differences between conditions were detected for EI. Cumulative activity-EE (HCLF= 20.9 ± 3.7, LCHF= 16.9 ± 3.1 MJ; p = 0.037), but not total-EE (HCLF= 44.6 ± 7.7, LCHF= 39.9 ± 4.7 MJ; p = 0.060), was higher for the HCLF condition than the LCHF across the measurement period.

Conclusion: Compared with low carbohydrate/high fat, immediate post-exercise energy replacement with a high carbohydrate/low fat drink resulted in higher short-term activity energy expenditure and lower appetite ratings.