Free school meals, diet quality and food insecurity in secondary school students: protocol for a multiple-methods study - the CANTEEN study.

introductionFood insecurity is increasing in the UK, impacting choice and diet quality. The current means-tested free school meals (FSM) policy was put in place to address dietary inequalities and food insecurity in school children. In secondary schools, approximately 20% of students who are eligible and registered do not take their FSM. Working across a range of schools that have variable levels of FSM uptake, this study aims to evaluate the effectiveness and cost-effectiveness of the current means-tested FSM policy in UK secondary schools on diet and food insecurity outcomes, understand what factors are associated with uptake and test the potential impact of any proposed policy change.Secondary schools (n=32) in both Northern Ireland and the Midlands region of the UK are being recruited into the study. Data will be collected from school staff, governors, students and parents via questionnaires, as well as observational data of school eating environments. Qualitative data will be collected in selected case study schools (n=6-8). Multilevel modelling will be undertaken to evaluate the association between FSM uptake and fruit and vegetable intake, overall diet quality and food insecurity in all students. Economic evaluation will be conducted using a cost-utility approach. The effect of policy change will be modelled and school factors associated with FSM uptake explored using multiple methods. ETHICS AND DISSEMINATION: Ethical approval has been obtained from Queen's University Belfast Faculty of Medicine, Health and Life Sciences Research Ethical Committee (MHLS 23_55). Findings will be disseminated to key national and local agencies, to schools through reports and presentations, and to the public through media and open access publications.