Gov. Brad Henry signed a bill on Monday to combat childhood obesity by doubling the amount of class time devoted to physical activity and nutrition programs for the state's youngest students. The amount of physical activity will increase from 60 minutes a week to 120 minutes a week. The requirement will apply to students in kindergarten through the fifth grade. Henry said junk food and an increasingly sedentary lifestyle are taking a serious toll on the health of Oklahoma's young people. Senate Bill 1186 will greatly strengthen physical activity for children, but much more remains to be done," he said. "Ultimately, parents are the most effective role models. "I urge Oklahoma parents to remember that their lifestyles are of paramount importance when it comes to instilling their children with right ideas about nutrition and exercise." Since 1980, the percentage of Oklahoma children who are overweight has more than doubled, and rates for teenagers have tripled. Fifteen percent of Oklahoma teenagers are classified as severely overweight or obese, a 300 percent increase in 20 years. On hand for the bill signing were the bill's main sponsors — Sen. Mary Easley, D-Tulsa, and Rep. Ann Coody, R-Lawton — as well as members of the Oklahoma Fit Kids Coalition, which pushed for the legislation, Public Health Commissioner Mike Crutcher and Sandy Garrett, school superintendent. Crutcher said increased physical activity will help children avoid becoming obese and developing such diseases as diabetes. "We know that healthy bodies build strong minds," Garrett said. "We want all of Oklahoma to keep moving." A 2004 study found that only 37 percent of Oklahoma school children were enrolled in physical education courses, compared to a national rate of 55 percent. "The experts are telling us that obesity will soon replace tobacco use as the number one preventable cause of death and disability in the United States," said Anne Roberts, director of the Oklahoma Institute for Child Advocacy.