School-Based Interventions to Reduce Obesity Risk in Children in High- and Middle-Income Countries

School-based interventions are relatively new and were first introduced in the United States in the 1990s. Early programs were mainly education based with many of the findings now embedded in school policy in the form of a healthy eating curriculum. More recent school programs have taken education outside the classroom and attempted to engage parents as well as teachers. Environmental changes such as improving the quality of foods available at lunchtime and at other times during the school day are now common. Reviews of evaluations of school-based programs have demonstrated that they are effective and successfully improve dietary quality such as increasing fruit and vegetable intake and decreasing sweet and savory snacks and sweetened drinks; not just in school but over the whole day and particularly in younger school children. School-based interventions are also effective at reducing obesity if components to increase physical activity and reduce sedentary behaviors are also targeted but not if only dietary behaviors are tackled. Most of the high-quality evaluation studies using randomized controlled trials have been carried out in high-income countries as they are costly to run. However, middle-income countries have benefitted from the information available from these evaluation studies and many are now starting to fund and evaluate school-based programs themselves, resulting in unique problems such as concomitant under- and overnutrition being addressed. Action for the future demands more focus on populations most at risk of poor dietary quality and obesity in order to reduce inequalities in health and on adolescents who have not benefited as much as younger children from school-based interventions. This will involve innovative solutions within schools as well as targeting the food environment outside schools such as reducing the density of fast-food outlets and marketing of sweet and savory snacks and drinks.