BACKGROUND: Gender differences in health behaviors have been reported in many studies but casual mechanisms have been neglected. PURPOSE AND METHODS: This study examines 4 food choice behaviors in a large sample of young adults from 23 countries and tests 2 possible explanatory mechanisms for the gender differences-women's greater likelihood of dieting and women's greater beliefs in the importance of healthy diets. RESULTS: Women were more likely than men to report avoiding high-fat foods, eating fruit and fiber, and limiting salt (to a lesser extent) in almost all of the 23 countries. They were also more likely to be dieting and attached greater importance to healthy eating. Dieting status explained around 22% of fiber choices, and 7% of fruit, but none of the gender difference in salt. Health beliefs explained around 40% of the differences in each of the dietary behaviors and together they explained almost 50%. Gender differences in food choices therefore appear to be partly attributable to women's greater weight control involvement and partly to their stronger beliefs in healthy eating. CONCLUSION: Further research is needed to understand the additional factors that could promote men's participation in simple healthy eating practices.