Beyond the Plate: School-Based Food Policies and the Conditions That Shape Eating Behaviour - A Systematic Review

School food environments shape what children eat, and the policies that govern them have become an increasingly prominent lever for public health nutrition. This systematic review examines the effects of school-based food policies and programmes on the dietary intake of children and adolescents aged 6 to 15, with a focus on food consumption outcomes measured using validated food frequency questionnaires. A systematic search of four databases yielded 17 included studies spanning 12 countries, employing a range of school-based approaches including meal provision, competitive food restrictions, multicomponent interventions, and nutrition education curricula. Risk of bias was assessed using the Risk of Bias (RoB) 2 tool. Findings were mixed but patterned. Multicomponent interventions of at least one year's duration produced the most consistent improvements in dietary outcomes. A recurring asymmetry emerged across study types: reducing unhealthy food and beverage intake proved more tractable than increasing consumption of fruit, vegetables, and other nutritious foods. Knowledge-based interventions reliably improved nutrition knowledge without producing corresponding changes in dietary behaviour. Fruit intake was more responsive to school-based intervention than vegetable intake across multiple study contexts. These findings suggest that school food policy holds genuine potential for improving children's diets, but that structural and sustained approaches are more likely to produce meaningful change than short-term or education-only programmes. The implications of policy design for children's broader relationship with eating are also considered.