Not long ago, the secret to losing weight seemed straightforward: Just give up bread. Not long before that, it was all about avoiding fat. And when those theories sprung leaks, a long list of diet fads was there to fill the holes — cabbage soup, grapefruit, eating for your blood type ... the list goes on and on.
To help you stop diet-hopping, we've peeled away the layers of hype to reveal the core concepts and surprising science behind what really works for women's weight loss. Follow these nine laws for hitting that perfect body number on the scale — and stay lean for life.
Law #1 Carbs don't matter. Calories do.
Atkins, South Beach, and other low-carb plans have allowed many of us to feel the thrill of slipping back into our skinny jeans. But those diets worked for one simple reason: We ate less. A 2004 review of low-carb diets in the medical journal The Lancet found that how long you stay on a diet and how much you restrict your calorie intake are the only factors that determine weight loss — not how much you cut back on carbs. "Every diet involves fewer calories than your body needs [to maintain your current weight]," says Betty Kovacs, R.D., codirector of the New York Obesity Research Center Weight Loss Program. When you swear off carbs, you abandon bread, rice, pastas, and desserts — high-calorie staples for most of us.
Make it Work for You
Set a daily calorie limit. First, ballpark how many calories you need to maintain your current weight. Multiply your weight in pounds by 10; add a few hundred if you exercise regularly, says Tara Gidus, R.D., a dietitian in private practice in Orlando and a spokeswoman for the American Dietetic Association. For example, a sedentary 140-pound woman needs about 1,400 calories a day; an active one might need 1,700.
Then decide how fast you want to lose the weight. A pound of body weight equals 3,500 calories, so shave 500 a day from your count and you'll drop a pound a week. Have oatmeal with skim milk for breakfast today instead of a bran muffin and you're already more than halfway there.
What should your calories consist of? The optimal balance, according to a review of studies on diet composition in the May 2005 Journal of the American Dietetic Association: 35 to 50 percent carbs, 25 to 35 percent fat, and about 25 to 30 percent protein. Check out WH's "Best 100-Calories Snacks" for tips you can take to the deli.
Law #2 Don't crash diet.
And not just because you'll get so hungry that late-night refrigerator raids become inevitable. Your body thinks you're starving when you lose too much too fast. So instead of burning calories, it conserves them in the form of fat, Kovacs says. In fact, as many as half of the pounds you drop during crash dieting come from muscle rather than fat. And because muscle stokes your metabolism — the speed at which your body turns food into energy — losing muscle means you'll burn fewer calories. For WH's take on why diets don't work, see "Diet's Demise."
Make it Work for You
Aim high, go slow. A new study from the University of Minnesota found that people who hoped to lose a lot of weight were more apt to get thin than those who didn't think as big. To keep muscle, don't try to lose more than a pound a week. But in the meantime, go ahead and buy that dress in a size 6. It may hang in your closet for 5 months — a healthy and realistic amount of time to lose 20 pounds — but it will be a powerful incentive.
