Towards sustainable school meals: integrating environmental and cost implications for nutritious diets through optimisation modelling

Food consumption patterns are currently at the heart of sustainability debates globally, with many studies calling for decreases in Animal Source Foods (ASF) consumption. This has been increasingly argued for school meal schemes, considering their sheer size and the fact that by targeting young people they have the potential to enable long-term changes in consumption habits. However, the potential and consequences of dietary transitions away from ASF in school catering services are still under investigation. This work analyses the environmental and costing implications of ASF reduction in school canteens, exploring the possible sustainability impacts of menus based on individual ingredients for a set of Italian schools. We use a mixed-method approach that combines optimization models, life cycle assessment, life cycle costing, and stakeholder consultation. The linear programming method is employed here to design four alterative school meal scenarios, starting from the menus currently served (SCB). Scenario 1 minimizes beef and dairy consumption, Scenario 2 minimizes pig and poultry consumption, Scenario 3 minimizes the consumption of all meat and dairy products, and Scenario 4 maximizes the consumption of pulses. Each scenario is then assessed through a cradle-to-grave life cycle assessment approach for key economic (i.e. costs) and environmental impacts (i.e. greenhouse gas emissions). Results suggest that reducing ASF in school food schemes can ensure nutritional quality and at the same time have environmental and economic benefits. The largest benefits accrue when minimizing beef and dairy (SC1), leading to a 22% reduction in Global Warming Potential (GWP) and an 1% reduction in cost per meal. The minimization of pig and poultry products in SC2 increases the GWP by 2% and costs by 3%, while the minimization of all meat and dairy products reduces GWP by 12% and increases meal cost by 4% (SC3). Finally, by maximizing pulses intake, the GWP per meal decreases by 12% and the cost by 1% (SC4). Overall, food procurement has the highest environmental impact and meal preparation the highest economic impact. Further research should investigate the acceptability of such menus, and translate the theoretical findings of our model into more practical day-to-day school meal options.