Bowling Green High Principal Fred Carter remembers what physical education was like when he was a kid. The P.E. teacher back then just rolled you a ball and said, You guys play, he said. Today, Bowling Green High offers a plethora of P.E. classes, including aerobics, basketball, baseball, weightlifting and swimming. The school also is working on a project that may include canoeing and kayaking in the curriculum as early as next year. Its a far cry from the days when Carter played lots of dodge ball. But in spite of the slew of new courses, obesity in youth has doubled over the past 20 years. A study by the National Education Association shows that one in five children is overweight. The causes of obesity are as varied as the ways to fight it. The Centers for Disease Control and Prevention, in a study released this week, report lack of physical education in schools as one of the problems. Other experts say that a lack of P.E., combined with more consumption of high-calorie foods and long periods of sitting in front of the television or computer, are the problems. When I came home, there was no Internet or computer to play on, Carter said. There also werent McDonalds restaurants and convenience stores scattered all over Bowling Green. There werent vending machines packed with junk food inside schools. Warren Central High Principal Barry Dye said that in his 27 years at the school, the P.E. requirements havent changed. Kentucky high schools require students to have physical education and health their freshman year, Dye said. After that, students can choose from any of the optional advanced classes. He said lack of physical education may not be the problem. My personal opinion is that our society today lends itself to being more obese, he said. Students tend to drive to school or ride the bus instead of walking, he said. They tend to frequent fast food restaurants after school. Its possible that the solutions to student obesity start at the elementary level. Cheryl Harlow, a P.E. teacher at Bristow Elementary School, said her classes meet three times every two weeks. I dont think its enough, she said. Ideally, students would have some type of physical activity every day. She encourages teachers to take the kids for a walk on days they dont have P.E. class. She also said an in-class exercise break every hour or so might be a good idea, citing a study that shows exercise helps blood flow to the brain.