This article reports the findings of a statewide study evaluating the body weights of nearly all public school students in Arkansas. Researchers in Arkansas analyzed "body-mass index" data for more than 345,000 students at all grade levels in 93 percent of the state's public schools during the 2003-04 school year. Based on the data, the researchers calculated that 21 percent of students were overweight and that 17 percent were at risk of becoming overweight. The study used the federal government's definition for body-mass index, which is calculated by comparing a person's weight in relation to height.