According to the Centers for Disease Control and Prevention, the percentage of children between the ages of 6 and 11 who are dangerously overweight has more than doubled between 1980 and 2012, and the obesity rate has quadrupled among adolescents. Those extra pounds, the CDC says, are putting kids at risk for an array of adult health problems, ranging from heart disease and diabetes to cancer.
That alarming trend has led a lot of adults to complain that kids these days would be slim and fit if they just had physical education (P.E.) in school. The problem, they think, is that many schools have been de-emphasizing it because of budget cuts and the need to spend more time on academics [source: Baker].
But studies have found that increasing the number of days in which kids have gym doesn't seem to have any consistent effect upon body-mass index or the prevalence of obesity. It's difficult in a school class to achieve the amount of activity and calorie expenditure needed to make a difference [source: Casazza et al.].