Co-creation and implementation of a healthy lunch at Dutch primary schools in disadvantaged neighbourhoods: design of a cluster randomised cross-over effectiveness study.

Introduction: The majority of children fails to have a healthy diet. Providing a healthy lunch at school is a way to target all children, regardless of ethnic and socioeconomic background. This study aims to investigate the effectivity and feasibility of a co-created healthy school lunch in disadvantaged neighbourhoods of the city of Rotterdam, the Netherlands.

Methods And Analysis: This is a cluster randomised cross-over trial with five participating primary schools. Schools will be randomised to have an 18 week healthy school lunch the first or second half of the academic year. The other half of the academic year, children will bring their own lunch from home. A tailored lunch concept for each school will be co-created with school staff, parents, children and key-stakeholders.Primary outcome is the dietary content of children's lunches, assessed by observations for all children. Secondary outcomes include healthy lunch-related parameters, like general dietary behaviour, perceived health, taste preferences, concentration in class, and some feasibility outcomes, like satisfaction, implementation at school and affordability for parents. Secondary outcomes will be assessed by questionnaires for children (grades 5-8), parents and teachers. The observations and questionnaires for children and parents will be completed at baseline (September 2023), half way the academic year (January-February 2024) and at the end of the academic year (June-July 2024). Teachers will complete a monthly questionnaire starting in September 2023.

Ethics And Dissemination: This study obtained ethical approval from the Institutional research Review Board Erasmus MC of Rotterdam, the Netherlands. Informed consent will be collected from all participants (parents, teachers and children 12 years or older) and/or their parents (for children under the age of 16). The findings will be disseminated by conference presentations and publications in scientific peer-reviewed journals.

Trial Registration Number: NCT06058325.