Ask anyone with a six-pack and they'll tell you that a great physique is often built more in the kitchen than in the gym. And it's not just that you can't put down the junk food. A lot of guys think that they're making the right choices, but those well-intentioned miscalculations could throw off your gym progress or set back your weight loss goals. Here are three of the most common mistakes and how to fix them to get back on the road to a better body.