Hunger often hinders sociality and well-being. Why, then, do many religions require members to become hungry by practicing fasting? Moreover, fasting periods are often accompanied by calls for charitable giving. We outline a new project designed to examine the seemingly paradoxical effects of religious fasting on prosocial behavior and well-being across several religious traditions. We will use a variety of approaches, including Google search data, survey data, field experiments, and lab experiments to explore these effects and their potential mechanisms.