Sustainability on a plate : footprint reduction and nutritional improvement through meal optimization in university canteens

The globalized food system allows unrestricted access to food throughout the year, yet this convenience comes at a high environmental and health cost. In Switzerland, approximately 25% of the environmental impact is attributable to food consumption, while diet-related diseases and associated costs continue to rise. To address these challenges, the Menu Sustainability Index (MSI) was developed as a scientifically grounded tool for evaluating lunch menus in community catering with regard to both environmental sustainability and nutritional balance. At the University of St. Gallen, which aims to achieve climate neutrality by 2030, the MSI was implemented in campus catering. Over an 11-week baseline period and a 3-week intervention phase, the environmental and nutritional quality of meals was assessed and optimized. Metrics included global warming potential (IPCC 2021), overall ecological impact (Ecological Scarcity Method 2021), and nutritional balance (Müller & Berger, 2018). Recipe adjustments and targeted communication led to measurable improvements. During the intervention, 9,800 meals were sold with 14.6 tons CO₂-eq emissions—3.1 tons less than the reference period, equating to a 23% reduction in average emissions per meal. Meat-based menu sales dropped from 78% to 53%, and the average nutritional balance improved from –11.5 to –6 points. Survey results showed that 70% of guests value ecological sustainability and 90% value healthy meals. Findings demonstrate that replacing high-impact foods—especially meat and dairy—with more sustainable alternatives significantly reduces environmental impact while improving dietary quality, contributing to behavior change and institutional sustainability goals.