The world is facing a global climate crisis and a collective step towards a more sustainable lifestyle is of importance. Food consumption accounts for a large part of an individuals’ total emissions and as the production of meat generally emits less green-house-gases than that of plant-based alternatives, changing towards a more plant-based diet can be one step to a more sustainable lifestyle. This study outlines a field experiment at a university cafeteria where the menu order was altered by random assignment. It is tested if placing the vegetarian option at the top of the menu has a causal effect on the share of vegetarian option sold that day, i.e. if it is possible to nudge customers to choose a more sustainable option. Using ordinary least squares and a beta regression models, the results do not show a positive treatment effect on the share of vegetarian option sold but do find a significantly average negative effect of 5.5 percentage points on the share of meat option sold. This effect it translated to an average negative effect of 6 percent on the daily emissions due to food sales at the cafeteria.