The study involves 14 schools on the Pine Ridge and Rosebud reservations, which are two Lakota reservations in South Dakota. Seven schools will be randomly assigned to the intervention condition and 7 schools to the control condition. Schools will be assigned to one of the two groups after baseline measures have been completed. The focus of this intervention, the Ohiyu lyojanjan - Bright Start Program, is to create dietary and physical activity environmental change at school and home. The intervention will follow 500 children in kindergarten for 16 months through the end of 1st grade. There will be 4 schools on the Rosebud reservation and 10 schools on the Pine Ridge reservation assigned to two groups. The two groups will begin the study one year apart; the first group will have baseline measures assessed in the fall of 2005 and begin the intervention in January 2006, and the second group will have baseline measures assessed in the fall of 2006 and begin the intervention in January 2007. This staggered design will allow for more contact with participating schools and families by key study staff, increased monitoring and control of the intervention within schools, and decreased staff costs. The intervention will focus on changing the school and home environments related to physical activity and food. The school physical activity environmental intervention component will incorporate 60 minutes of daily physical activity at school for kindergarten and 1st grade students through a combination of physical education classes, a classroom walking program, in-class activity breaks, and active morning and afternoon recess. The school food environment intervention will focus on improving school meals (breakfast and lunch), classroom snacks, and teacher classroom food practices. The intervention will target the school food service to decrease availability of high-fat and high-sugar foods, regulate portion control of foods served, and increase fruits (not juice) and vegetables served. The family intervention will address the household food and physical activity environment and family dietary and physical activity behaviors. Because parents of kindergarten children in the selected schools will be recruited for participation prior to the school treatment assignments, it may be problematic to engage all parents without providing anything to those who are assigned to the control condition. To foster parent interest in study participation, parents in the control group will be mailed monthly newsletters with general family recommendations for prevention of excess weight gain.