The extent to which breakfast covers the morning energy expenditure of adolescents with varying levels of physical activity

Abstract

Background: Energy intake at breakfast affects the performance of creativity tests, memory recall and voluntary physical endurance in children before lunch, and food craving during the whole day. Objective: To assess the adequacy of breakfast energy supply (BES) and energy expenditure (EE) in adolescents during a schoolday without or with 2 h of physical education lesson (PEL) in the morning. Design: Sixty adolescents (four groups of 14–16 boys and girls aged 12–16 y) participated in a cross-sectional study. Activity patterns and EE were determined by whole-body calorimetry during 36 h and in free-living conditions during 5 days using both a diary and the validated heart rate recording method. BES was determined by weighing individual foods. The pyloric energy flow was assessed using a model of fractional stomach emptying. Results: BES averaged 24.9% (s.d.=6.1) of daily EE in the four groups of subjects. It covered the mean morning EE on a schoolday without PEL, but not in a schoolday with 2 h of PEL in any group. When PEL took place from 8–10 am the cumulative EE exceeded the cumulative pyloric energy flow after 105–150 min, that is during the PEL session, and the energy deficit increased until lunch. With a light breakfast (BES−1 s.d.) energy deficiency happened after 90 min. Conclusion: The results stress the need for a heavy breakfast for children and adolescents on the days with PEL in the morning, and a carbohydrate rich snack at 10 am to improve attention, memory and willing participation in physical activities.