Dietary habits across the primary-secondary school transition: A systematic review

Introduction: The transition to secondary school involves significant changes in children's social and physical environment, which are often accompanied by changes in dietary habits. However, evidence around how dietary habits change during this life-stage transition is variable. Objective: This review aimed to identify, critically appraise, and summarise the wide-ranging evidence on changes in dietary habits across the primary-secondary school transition. Methods: Four electronic databases (PubMed, Embase, Web of Science, and Scopus) were searched for relevant studies published in English or Spanish from inception to February 2024. Longitudinal studies with a baseline quantitative assessment of dietary habits when children were in their last year or two of primary/elementary school with at least one follow-up assessment of dietary habits when children were in their first or second year of secondary/middle/junior-high school were eligible for inclusion. Results: Seven studies (10 independent samples) were eligible for inclusion, and fourteen different dietary habits outcomes were reported across the seven studies. The frequency of consuming breakfast, fruit, vegetables, and milk decreased across the primary-secondary school transition. Inconsistent results were found regarding changes in the frequency of consumption of sugar-sweetened beverages, fruit juice, snacks, and fast-foods. Many dietary habits were only evaluated in single studies. Conclusions: There is moderate evidence for a decrease in the frequency of consumption of breakfast, fruit, vegetables, and milk in children across the transition from primary to secondary school. This highlights this timeframe as a valuable period for intervention to promote the continuation of positive dietary habits. More high-quality longitudinal studies using homogeneous methodologies to evaluate changes in dietary habits across the school transition are needed to fully understand the implications of this transition on children's diet and health behaviours.