Feel Good Study: Studying the relationship between fruits, vegetables, and children’s mental well-being.

This study is a cluster randomised controlled trial amongst primary school students in school years 4-6 (ages 8-11), which has one intervention arm and one control arm (habitual diet). The intervention is a multi-component approach that focuses on increasing fruit and vegetable intake in children over a 10-week period in the school term. The intervention has been designed using behaviour change science, and the Behaviour Change Wheel is the theoretical framework underpinning the intervention. The multi-component intervention addresses key determinants of fruit and vegetable intake in children (availability/access, acceptance), and has the ambition to not only increase fruit and vegetable intake during the intervention, but to promote longer-lasting behaviour change beyond this trial alone. The 10-week programme is delivered in both the school and home setting and includes a weekly fruit box delivery to schools, a weekly vegetable box delivery to homes, sensory experiential learning at school which focuses on increasing acceptance of fruits and vegetables, and a home-based support package which includes recipes, preparation tips/tricks, and a study Facebook group to encourage engagement from the families of participating children. The food provision means that participants will have the opportunity to increase their fruit and vegetable intake by 1 serve each per day. The sensory experiential learning programme includes 6x 30 minute lessons, with the intention to deliver once a fortnight during the intervention though this can be adapted to school's preferences. This is a classroom-based programme, Successful elements from previous sensory experiential learning have been integrated into school lesson plans, using the Flavour School programme and Sapere method as a guide. The lessons have been developed and will be delivered by Registered Dietitians with at least 5y experience using the teaching manual. The aim is to positively prime children to eat fruits and vegetables by increasing their acceptance, and is based on a scientific framework of food preference development. Each lesson will be based on a different sense, and include worksheet activities, hands on learning, and opportunity to taste different fruits and vegetables. Contingent reinforcement will be achieved through role modelling, rewards (e.g., stickers) and activities incorporated both in the sensory lessons and home-based support package. The home-based support package is designed to reinforce children's learning at school, and provide longer-lasting benefits for families. Given that families will be receiving vegetable boxes, the home-based support package will be primarily focused on vegetable intake and acceptance. Components include recipes (using existing resources from reputable organisations, e.g., Heart Foundation, Love Food Hate Waste, or 5+ a day), preparation tips/tricks (e.g., maximizing preferred sensory qualities of vegetables), information around role modelling (e.g., importance of promoting vegetables as fun and tasty, not just for health). There will also be a study Facebook group which will be monitored by the research dietitians and include a weekly photo challenge, and videos/posts for inspiration (e.g., recipes, photos from class lessons). It is at participant’s discretion how much time they spend interacting with the different components of the home-based support package. The home-based support package components will be provided to participants in several mediums including hard copies with the vegetable box delivery (recipes), through the private study Facebook group, and in a weekly newsletter sent via email. Intervention adherence will be measured by changes in children's fruit and vegetable intake from baseline to the 10-week follow-up (collected through child- and parent-reported questionnaires on dietary intake). There is no specified serve size to compare adherence to for this pilot/feasibility study, and it is expected that this pilot/feasibility study will help define the required increase in fruit/vegetable intake for measuring adherence in a larger randomised controlled trial. Intervention fidelity will be measured in the process evaluation of this study. Components will include the number of interactive sessions delivered and whether the lesson objectives were met in each lesson, whether fruit boxes were delivered to schools as planned, whether vegetable boxes were delivered to home as planned, and what resources of the home-based support package parents/caregivers utilised. The process evaluation includes questionnaires/interviews completed by teachers, parents/caregivers, and children.