Approaches to weight management have traditionally focussed on caloric intake versus caloric expenditure. Despite a range of interventions based on these approaches, the proportion of overweight children and adolescents continues to rise. There are increasing indications that other factors, such as sleep duration, may be at play. This commentary on current research related to the impact of sleep duration provides an insight into the mounting evidence of its possible link to overweight in children and adolescents. Here we focus on children and adolescents as typical age cohorts in schools experiencing health and physical education programs. Children and adolescents are sleeping less than ever before, and there is now emerging evidence that sleep duration has a profound effect on weight regulating hormones leading to weight gain. It is proposed that a 24-hour view of children and adolescents be taken into account. Moreover, a reassessment of the impact of sleep deprivation may lead to extra considerations in the information and practices embodied in the HPE curricula for the growing battle against obesity. (Contains 2 tables and 3 figures.)