In Choices Magazine, behavior economists tackle the lunchroom cafeteria. (Via the Monkey Cage.)

In general, when schools require students to take vegetables, only about 35% of the students actually consume the vegetables, resulting in substantial waste of food and resources (see, for example, Price and Just, 2009). In fact, a recent study suggests that requiring students to take vegetables rather than allowing them to control this choice by selecting or rejecting vegetables has virtually no impact on vegetable consumption, while nearly doubling the waste from vegetables (Price and Just, 2009). Alternatively, consider what might happen if students were given the choice between carrots and celery. In a recent experiment we conducted at Cornell, 120 junior high participants in a summer 4H program were told they must take carrots with their lunch, while another 120 were given the choice of carrots or of celery (103 of 120 selected the carrots). Of those required to take the carrots, 69% (83 of 120) consumed the carrots, while 91% (94 of 103) of those choosing between carrots or celery consumed their vegetable. Such results suggest that requiring a vegetable, while offering an active choice between at least two options substantially reduces the waste from vegetables, and increases the nutritional content of the foods consumed.