Among the most commonly held misconceptions about obesity, perhaps none does more harm than the notion that exercise is responsible for the lion's share of weight management. Sure, it's true that exercise does burn calories, and yes, if you burn more calories you ought to lose weight. But unfortunately, it's just not that simple. To put exercise into some perspective, to lose a pound of weight each week would require roughly a marathon of effort each and every week, as the calories burned runni