Plant-based diets have been associated with several health benefits, but not much is known about their effects on mental health. A new Brazilian study published in the Journal of Affective Disorders surveyed more than 14,000 people between the ages of 35 and 74 for a period of six months and found that those following a vegetarian diet were twice as likely to have a depressive episode than meat eaters, even when other lifestyle factors like smoking, alcohol consumption, physical activity and micronutrient intake were taken into account. The nature of this correlation between vegetarianism and depression is still unclear, and more research is needed.