One in six American children was affected by obesity in 2000. In the city of Somerville, outside of Boston, 46 percent of Somerville first and third graders were overweight or at risk for becoming so. Dr. Christina Economos, an associate professor at the Friedman School of Nutrition and the School of Medicine at Tufts University worked with her colleagues in collaboration with the entire City of Somerville to design and implement Shape Up Somerville (SUS). Recognizing that children have limited control over the food and physical activity options available to them, the program sought to prevent obesity in early elementary school-age children through a community-wide initiative focused on environmental and policy strategies to impact energy balance. Over the 2003-2004 and 2004-2005 school years, Shape Up Somerville led to a statistically significant drop in Body Mass Index (BMI) among early elementary school children. As of 2012, Shape Up Somerville is part of the Somerville Health Department and an integral part of community efforts to improve healthy and active lifestyle options for the community.