Total energy expenditure and physical activity in prepubertal children: recent advances based on the application of the doubly labeled water method.

The prevalence of obesity in children has continued to increase despite a general increased awareness of health and fitness. Epidemiologic data show that the prevalence of obesity in children is approximately 25%, with a higher prevalence in some subgroups of the population. In addition, the incidence of obesity-related diseases is dramatically increasing in children. For example, the incidence of type 2 diabetes in children and adolescents has increased 10-fold over the past decade, and this increase is more pronounced in obese persons. The etiology of the development of childhood obesity and subsequent disease is poorly understood, but is likely to be explained by alterations in the regulation of energy balance between energy expenditure and energy intake. It is not known whether obesity is caused by an increase in energy intake relative to energy needs, a decrease in energy expenditure relative to energy needs, or the effect of both. This review will focus on recent studies that have attempted to elucidate the etiology of childhood obesity and have increased our understanding of the regulation of energy balance in prepubertal children by using the doubly labeled water method for estimating total energy expenditure and physical activity-related energy expenditure. This review serves as a brief summary and general update of recent reviews of this topic.