Americans didn't worry much about keeping fit 100 years ago. In those days 40% of the population was reaping and sowing, herding and mowing its way through life on preindustrial farms. In coastal cities, strong-shouldered stevedores were loading and unloading ships dawn to dusk without a container or stacking crane in sight. Builders, lumberjacks and railroad men drove nails or sawed wood with their muscles, not power tools. And for those doing the washing, cooking and scrubbing at home, life wasn't so dainty either. (Ever pick up one of those 8-lb. solid-metal weights that gave ironing its name?) In that bygone, sweat-drenched era, staying in shape just wasn't an issue. Indoor plumbing? Now that was an issue. Working out? Never heard of it.
One can only imagine what time travelers from that strenuous era would make of modern-day Americans, sitting on their duffs most of the day--in the car, at the office, in school, on the sofa--eating like a stevedore and then driving to the fitness club to log a mile or so on a conveyer belt. It just doesn't add up.
Literally. The old energy-balance equation--calories in should equal calories out--is seriously out of whack, as the rising rates of obesity in the U.S. and other developed nations prove. For much of the past decade, public-health officials, doctors and the popular press (including this magazine) have focused on the intake side of the equation. We're eating too much fat, too many carbs, too much altogether. But the problem is just as grave on the output side. We are not burning enough calories or moving our bodies enough to maintain good health. "We have two epidemics in this country. One is obesity, the other is physical inactivity," laments Dr. Tim Church, medical director of the Cooper Institute, a fitness research center in Dallas. "One is a topic of cocktail conversation and the focus of bestselling books. The other is ignored."
In this 21-page special report on getting America fit, TIME aims to address that imbalance. Why should we be concerned about fitness? Because as bad as it is to be overweight, it may be just as bad to be inactive. In fact, some health authorities believe it's worse. The health risks of obesity--diabetes, heart attack, high blood pressure and certain cancers, among others--are familiar to most Americans, but physical activity confers its own benefits "above and beyond what it can provide for weight control," says Harold Kohl, lead epidemiologist at the Physical Activity and Health Branch of the Centers for Disease Control and Prevention (CDC).