Nutritional Composition and Environmental Impact of Meals Selected in Workplace Canteens before and after an Intervention Promoting the Adherence to the Mediterranean Diet.

Enhancing healthy and sustainable food systems is one of the key goals of the current European Commission policy. In this light, the creation of a food environment where people are properly informed about the healthiness and sustainability of food choices is essential. This study aimed to evaluate the nutritional profile and the environmental impact of meals consumed in a workplace canteen in Italy in the presence of a nudge (i.e., the Double Pyramid logo) combined with a web-based application promoting the Mediterranean Diet. Energy and nutrient contents and the carbon, water, and ecological footprints of 29,776 meals were compared across three subsequent periods (from June to April) through one-way ANOVA. Although the choice of dishes labelled with the Double Pyramid logo was comparable across periods, the selection of fish- and plant-based dishes increased from +2% (fish, vegetables) up to +17% (whole-grain cereals), with a concurrent reduction of meat-based options (−2%). Although the consumption of healthy items increased (p < 0.001), they were not added as a replacement for alternative options, leading to a higher content in energy (p < 0.001) and nutrients (p < 0.001) and worse environmental footprints, contrarily to what was observed when data were adjusted for energy. The intervention significantly improved food choices; however, as the higher selection of desired dishes was not adequately compensated for, it was not fully effective.