Eat Enough

You need to cut calories to lose weight. But going too low delivers a double whammy to your metabolism. When you eat less than you need for basic biological function (about 1,600 calories for most men), your body throws the brakes on your metabolism. It also begins to break down precious, calorie-burning muscle tissue for energy. "Eat just enough so you're not hungry—a 150-calorie snack midmorning and midafternoon between three meals (about 430 calories each) will keep your metabolism humming."