Bonus Tip: This is just as important for women as it is for men. But don't be obsessed with the scale. Your weight can fluctuate up or down by up to 4 percent a day. So your best gauge is really the way your clothes fit -- especially your jeans. If they're feeling looser around your hips and waist, you're making progress.
Adam Campbell is co-author of "The TNT Diet," and the fitness director at Men's Health magazine.