The present study examined the effects of a school breakfast program on the activity level, emotional state, and social interactions of a group of Kenyan schoolchildren on the playground. Five hundred forty children in rural Kenya participated in the study. The first standard (grade) classes were randomly assigned to groups provided for 21 months with school breakfasts of equivalent caloric value while families with children in the control group were given a goat at the end of the study. The study aimed to determine whether enhanced caloric intake or diet quality influenced the children's behavior on the school playground. The results indicate that supplemented children were more active and showed more leadership behavior and initiative than did non-supplemented children. In addition, children given meat showed fewer periods of low activity and more leadership behaviors and initiative than did children provided entirely with vegetable source foods. These results support our previous findings from naturalistic studies in the same community that both diet quantity and quality are important for children's development.