For about a year now, I've been walking and occasionally lifting weights. If I burn about 300 calories during a workout, then a single candy bar would cancel the benefits of my workout. Still, I've managed to take off 12 pounds in the last year without changing my diet much. How is that possible?

Exercise offers tremendous advantages. It can improve your strength, lower your risk for heart disease and diabetes, and improve your mental outlook and agility. Exercise also burns calories. This calorie-burning effect continues even after you've stopped exercising. One study of female weight lifters showed that an hour after the women exercised, they were still burning many more calories than they were before exercising. And after 90 minutes, they were burning much more fat (79 percent more) than normal. So when you exercise, you continue reaping the benefits for some time afterward. Keep up the good work (but watch those candy bars)!