Is energy intake altered by a 10-week aerobic exercise intervention in obese adolescents?

Abstract

Aim: To examine energy intake adaptations to a 10-week aerobic exercise program in obese adolescents.

Methods: Twenty-six 12-17year old obese adolescents were asked to cycle twice a week for an hour in a research laboratory. Body composition, aerobic fitness (submaximal fitness test) and energy intake (3-day food record) were assessed before and immediately after the 10-week intervention.

Results: The average time spent pedaling per session was 55.3±12.1min for a mean energy expenditure of 2196±561kJpersession. The intervention produced significant improvements in percentage of body fat (44.5±10.6% vs. 43.4±9.8%; p<0.05) but no significant weight and fat-free mass change. Peak workload (79.5±20.8W vs. 87.3±17.6W; p<0.05) and peak heart rate (174.6±18.7bpm vs. 166.2±21.0bpm; p<0.01) were improved. The mean total daily energy intake (in kJ/day) showed a tendency to decrease through the intervention (7440±1744 to 6740±2124kJ; p=0.07) but a high inter-individual variability observed in the energy intake response to the intervention may explain the non-significant association between the energy intake response and weight loss.

Conclusion: A 10-week aerobic exercise program may result in a small decrease in energy intake and an associated decrease in percentage of body fat but no weight loss in obese adolescents. This lack of weight loss could be explained by a decrease in spontaneous energy expenditure outside the intervention sessions.

Trial registration: ClinicalTrials.gov NCT00983970.

Keywords: Energy expenditure; Energy intake; Pediatric obesity; Physical activity.