Oops-Proof Your Workout

For most women, sweaty aerobic exercise alone isn't enough. "Research shows that weight loss is minimal if it isn't accompanied by dieting," says Amy Luke, PhD, a nutritional epidemiologist at the Stritch School of Medicine at Loyola University Chicago. "We may compensate for the extra energy we're burning during physical activity by doing less the rest of the day, or more commonly, we feel famished after working out, so we eat more."

The Solution: Keep your diet in check. To drop a pound, which is 3,500 calories, in one week, aim to eat 300 fewer calories every day (300 x 7 = 2,100) while burning 300 calories from exercise five times a week (300 x 5 = 1,500). Follow our "Slimmer in 7 Days!" plan, not only to burn 1,500 calories a week but also to firm up from head to toe. Plus, to beat the post-workout hunger attack, pack a low-cal snack like a piece of fruit. "You plan for exercise. You need to plan what you're going to eat afterward," says John Porcari, PhD, a professor of exercise physiology at the University of Wisconsin at La Crosse and a FITNESS advisory board member. Drinking lots of water helps too.