Our objectives was to identify the characteristics of interventions likely to successfully prevent overweight in youngsters by promoting physical activity (PA), with special focus on dimensions of the socio-ecological model of behaviour and health, and unresolved issues.

This was a systematic review of population-based interventions either promoting PA or limiting sedentary behaviour in children with measure of weight status as an endpoint. The efficacy of studies was evaluated according to the levels of PA determinants in the socio-ecological model (individual, interpersonal, institutional environment, community) targeted by the interventions.

A total of 54 studies met our inclusion criteria, most of them published within the last 5years and targeting children aged 6–12years. Twenty-three interventions targeted individual and/or interpersonal PA determinants only; 26 targeted determinants at three or four levels with at least one environment component at the institutional level; and five were multilevel community-based interventions. Our review indicated that programmes targeting PA determinants at the different levels of the socio-ecological model, including the social and organizational/built environments, had the greatest potential for preventing obesity in youngsters. Targeting various facets of PA, including everyday PA, might represent another key element for program efficacy on weight status.

Data regarding the efficacy of comprehensive PA interventions that simultaneously address individual attitudes and skills, the social context, and the environment, to prevent overweight in children are encouraging. Further studies are needed to evaluate the maintenance of the effects and whether such strategies apply to young children and older adolescents, and to different cultural contexts.