Reducing the consumption of meat can make a significant contribution to sustainable development. However, at least in Western societies with their already rather high levels of per-capita meat consumption, only a minority of consumers reduces meat intake by following a vegetarian or plant-based diet. To arrive at a differentiated understanding of the conditions of meat avoidance, we empirically assess the importance of a broad set of specific motivations and constraints previously discussed in the literature, including specific benefits, particular constraints, social norms, and a vegetarian self-identity. The analysis is based on a random sample of students at the university of Zurich (Switzerland)—a social group exhibiting a rather high prevalence of plant-based diets and vegetarianism. Researching this young and educated population sheds light on the motivational underpinnings of consumer segments especially willing to reduce meat intake. Data were collected in November and December 2016. We found that a vegetarian self-identity, both injunctive and descriptive social norms, and convenience are the most important direct determinants of meat avoidance among this young and highly educated consumer segment. Furthermore, the results suggest that a vegetarian self-identity mediates the effects of ethical, health-related, and environmental benefits, taste as a constraint and partially the injunctive norm. Pecuniary costs of a vegetarian diet are not significantly correlated with meat avoidance.