Effective school food environment interventions for the prevention of childhood obesity: systematic review and meta-analysis

BackgroundThe food environment is a modifiable enabler of dietary choices that can have a great impact on the prevention of childhood obesity in the UK. It is defined as a combination of physical, economic, political, and sociocultural surroundings as well as opportunities and conditions that influence food choice. Many interventions have been undertaken at the school level but evidence of their effectiveness in the reduction of childhood obesity is scarce. Therefore, we aimed to synthesise and evaluate the evidence of food environmental interventions around and within schools to determine effective parameters that can aid in childhood obesity prevention.MethodsWe searched CINAHL, Embase, Global Health, MEDLINE, Scielo, and Cochrane databases. The considered population were children aged 18 years or younger. Interventions focused on modification of the food environment in schools to prevent obesity and improve dietary intake. Outcomes included anthropometrical measures and dietary intake. The protocol was registered with PROSPERO (CRD42019125039). A second reviewer did a reliability check on 10% of abstracts, bias, and full-text review.FindingsBetween Jan 1, 2000, to Feb 12, 2019, we retrieved 4307 studies, of which 21 were included after screening. Interventions (13; 62%), policies (two; 10%), and laws (three; 14%) from eight countries, including the UK, were included. Four (19%) interventions focused on vending machines. Study designs included natural experiments (one; 5%), quasi-experiments (two; 6%), non-randomised (one; 5%), and randomised (four; 19%). The main outcomes were body-mass index z score (13; 62%) and dietary intake (n=4, 19%). A positive association (p=0·0451) was found in 15 (71%) studies between 0·89% and 1·29% reduction in obesity prevalence. The most frequent interventions were vending machines, school stores, cafeterias, and menu offering regulations.InterpretationIdentified effective interventions in the prevention of childhood obesity were banning of sugary drinks in schools and an increase in availability and accessibility of fruits and vegetables for children from an early age. Multisystem approaches, such as stringent and monitored school meal programmes, alongside the collaboration, training, education, and integration of the school staff, parents, and students, increased acceptability and adaptability according to the local needs and sustainability of the food environment interventions. Changes in the environment lead to individual behaviour modifications.FundingEuropean Commission (H2020 SC2).