Dietary similarity of friends and lovers: Vegetarianism, omnivorism, and personal relationships.

In a series of studies conducted in the USA and Poland, we found that vegetarianism can serve as a basis for the formation of personal relationships. Consistent with research on the similarity-attraction effect, we found that vegetarians were more likely than omnivores to have friends and lovers who were vegetarians. In study 1, vegetarians reported that their diets were a more important part of their identities than omnivores did. In studies 2, 3, and 4, we found that vegetarians were three to six times more likely to have vegetarian friends than omnivores were. In study 4, we found that vegetarians were 12 times more likely to have romantic partners who were vegetarians than omnivores were. These results suggest that following a vegetarian or an omnivorous diet is an important influence on an individual's choice of relational partners, possibly because dietary choice is part of an individual's social identity.