Fostering Healthy and Sustainable Diets Through School Meals (OPTIMAT Uppsala)

School meals have considerable potential to shape children's diets and reduce the climate impact of meals. This study applies linear programming for developing and implementing a climate friendly, nutritious and affordable school lunch menu. The new menu plan will be compared to the baseline menu during a 4-week intervention trial. The outcomes will be food waste, consumption, and pupils' satisfaction with the meals before and after introducing the new meal plan analyzed by interrupted time series analysis. Our hypothesis is that school meals can be optimized to be nutritious and more climate friendly, without negatively affecting acceptance, food waste and cost. Four primary schools in one Swedish municipality with the same menu plan for all schools will participate in the study. Their current meal supply will be recorded in the form of a food list including amount and cost of each item over a 4-week period. This list will then be optimized with linear programming to be as similar as possible to the baseline diet but with a reduction in greenhouse gas emissions of about 30%. No new foods will be introduced and none will be removed from the list. Nutritionally adequacy will be ensured by including constraints into the model. The optimized food list will be handed to the municipality's meal planner and a new menu plan will be developed based on the revised food list. Data on food waste and consumption will be collected daily during a baseline period of four weeks, and during the four-week intervention period. School lunch satisfaction will be assessed twice with an online questionnaire at baseline and during the intervention.