You don’t have to spend much time with teenagers to know that the average adolescent would rather devote an afternoon to sitting in front of the TV, computer or video-game console than working out in a gym. And in recent years, as physical-education classes have been progressively cut from cash-strapped public-school curriculums, teens have had even more time to lounge, slouch, hang out or do anything but break a sweat.
It’s no surprise, then, that obesity rates among U.S. youngsters have skyrocketed, tripling from 1976 to 2004. Public-health experts and obesity researchers attribute the trend in part to kids’ increasingly sedentary lifestyles. As teens spend more and more time anchored before a screen burning fewer and fewer calories each day they’re storing more of that unused energy as fat. Hence, the ballooning rates of obesity.