Eating within planetary limits - Life cycle assessment of food waste prevention and dietary shifts in Danish universities

Growing attention to food waste and the transition toward plant-based diets has intensified the need for evidence on how institutional catering can reduce its environmental footprint. This study assesses the environmental performance of meals in Danish university canteens by combining life cycle assessment with two years of empirical production and consumption data from cloud-based buffet scales. Across commonly sold menus, plant-based meals had inherently lower environmental impacts, yet their impacts were significantly increased by higher surplus rates driven by overestimated portion sizes. Waste-adjusted modelling showed that correcting these planning inaccuracies through digital monitoring could reduce per-portion climate impacts by up to 0.15 kg CO 2 -eq, with the largest improvements observed for plant-based meals. When surplus was eliminated, plant-based menus approached PB-aligned lunch thresholds, whereas animal-based meals exceeded these limits under all scenarios. Ingredient-level hotspot analysis further revealed that items such as cheese and rice contribute disproportionately to higher environmental impacts, highlighting the need for careful recipe design. Overall, the findings demonstrate that sustainable institutional food systems require not only a shift toward plant-based menus but also precision in production planning to minimise avoidable surplus and align meal provision with climate goals.