Abstract
The present study examined changes in the rates of vegetarianism among a sample of young American adults. Over 15 years, students at an American university (N = 12,704) described their dietary habits. Multilevel modeling analyses (participants nested within semesters) found that overall, the percentage of vegetarians increased over time, whereas the percentage of omnivores decreased over time; however, these changes occurred only for women. The dietary habits of men did not change over time. In a second study, in a sample of 363 adult vegetarians from the US, we found that women were more likely than men to become vegetarians due to concerns about the ethics of raising animals for food and eating them, suggesting that increased societal concern about animal rights may be responsible in part for the gender differences over time in vegetarianism. These results extend existing research on gender differences and suggest that if current trends continue, gender differences in vegetarianism may be more pronounced in the future.