In a transdisciplinary field experiment in two Swiss university canteens over 12 weeks, how customers respond to a revised menu choice of meat dishes and ovo-lacto-vegetarian or vegan dishes was investigated. Several interventions were implemented: the vegetarian menu line was abolished, the meat and veg-dishes were randomly distributed across the three menu lines, vegetarian and vegan dishes (veg-dishes) were not labelled or marketed as such, and in the 6 ‘intervention weeks’ the share of veg-dishes was increased compared to the 6 ‘base weeks’. Based on the lunchtime eating habits in the canteen, regular canteen visitors were categorised into either seven or five different ‘lunch types’. During the intervention weeks, the share of meat dishes decreased for every lunch type, although with different response patterns. It is particularly noteworthy that customers with meat-oriented lunchtime eating habits ate in the canteen more frequently. This indicates that the usual choices in the two canteens are more appealing for meat-eaters. Overall, the data show a clear potential to reduce meat consumption in canteens by increasing the range of attractive veg-dishes without explicitly marketing them as vegetarian or vegan. We conclude this also to be an economically profitable strategy, as it provides a chance to attract customers with veg-oriented lunchtime eating habits without either losing meat eaters or meat lovers.