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Systematic review and meta-analysis of the association between childhood overweight and obesity and primary school diet and physical activity policies

Andrew James Williams12, William E Henley1, Craig Anthony Williams2, Alison Jane Hurst1, Stuart Logan1 and Katrina Mary Wyatt1*

Author Affiliations

1 Institute of Health Services Research, University of Exeter Medical School (formerly Peninsula College of Medicine and Dentistry), Veysey Building, Salmon Pool Lane, EX2 4SG, Exeter, Devon, UK

2 Children’s Health and Exercise Research Centre, Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Heavitree Road, EX1 2LU, Exeter, Devon, UK

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International Journal of Behavioral Nutrition and Physical Activity 2013, 10:101  doi:10.1186/1479-5868-10-101

Published: 22 August 2013


Obesity is a major public health concern and there are increasing calls for policy intervention. As obesity and the related health conditions develop during childhood, schools are being seen as important locations for obesity prevention, including multifaceted interventions incorporating policy elements. The objective of this systematic review was to evaluate the effects of policies related to diet and physical activity in schools, either alone, or as part of an intervention programme on the weight status of children aged 4 to 11 years. A comprehensive and systematic search of medical, education, exercise science, and social science databases identified 21 studies which met the inclusion criteria. There were no date, location or language restrictions. The identified studies evaluated a range of either, or both, diet and physical activity related policies, or intervention programmes including such policies, using a variety of observational and experimental designs. The policies were clustered into those which sought to affect diet, those which sought to affect physical activity and those which sought to affect both diet and physical activity to undertake random effects meta-analysis. Within the diet cluster, studies of the United States of America National School Lunch and School Breakfast Programs were analysed separately; however there was significant heterogeneity in the pooled results. The pooled effects of the physical activity, and other diet related policies on BMI-SDS were non-significant. The multifaceted interventions tended to include policy elements related to both diet and physical activity (combined cluster), and although these interventions were too varied to pool their results, significant reductions in weight-related outcomes were demonstrated. The evidence from this review suggests that, when implemented alone, school diet and physical activity related policies appear insufficient to prevent or treat overweight or obesity in children, however, they do appear to have an effect when developed and implemented as part of a more extensive intervention programme. Additional evidence is required before recommendations regarding the focus of policies can be made and therefore, increased effort should be made to evaluate the effect of policies and policy containing intervention programmes upon weight status.

Policy; Obese; Nutrition; Physical education