Rural children are less active and more at risk for overweight and obesity than their metropolitan counterparts, suggesting that the rural environment may be more obesogenic.  The goal of this study was to examine the impact of middle school nutrition and physical activity policies and environments on adolescents' 3-year change in body mass index (BMI) in a rural setting.  Investigators also looked at the interaction between middle school nutrition and physical activity policies and environment and adolescents' socioeconomic status on 3-year change in BMI during middle school.  The population of interest was 12 to 15 year-old adolescents living in 8 rural counties served by Bassett Healthcare in rural, central New York.