The Skinny on Getting Thin

Americans are famously losing the battle of the bulge—two thirds of the adults in the United States are overweight or obese.  In "Rethinking Thin: The New Science of Weight Loss—and the Myths and Realities of Dieting" (Farrar, Straus and Giroux, May 2007), The New York Times science and medicine writer Gina Kolata explores why it's so hard to lose weight and keep it off.  According to a Consumer Reports survey out this week, 41 percent of the adult population is trying to lose weight and their average goal is a whopping 37 pounds. Kolata talks with NEWSWEEK's Karen Springen about our national obsession with dieting and the science behind weight-loss failures. Excerpts:

NEWSWEEK: The Consumer Reports survey shows that 90 million U.S. adults are currently dieting—and they they're aiming to lose a lot of weight—37 pounds, not just five or 10.  Why can't we lose weight on diets?
Gina Kolata: It's interesting how many people diet and how many people diet repeatedly. Sometimes they have unrealistic expectations of what they're biologically able to sustain. For some people, a 30- or 40-pound weight loss is biologically impossible. There are just some things your body won't let you do. On the other hand, I'm not anti-diet. When you start a diet, it's actually very empowering. You feel really good. Usually you're not hungry in the beginning, you feel in control, you're really happy. And then, after awhile, when some of the weight starts coming back, as it usually does, you don't say, "Boy, was I a fool to try a diet." You say, "I failed. I just fell apart. I had that birthday cake and that just set me off. It was my fault." Then another diet comes along. Women also go out and buy cosmetics [hoping to remake themselves]. You're promised if you put this thing on your face, you'll look 20 years old.

So are the diet merchants peddling the same thing as the cosmetics marketers?
It's like they're selling dreams. I don't think there's anything wrong with aspirations and dreams. The problem is when you start to beat up on yourself. You can eat healthy and exercise and do all the things you're supposed to do, and you may not be really skinny. That doesn't mean you're ugly or unacceptable or even out of control. I wish people would realize that most people who've tried to lose weight have tried very, very hard. One guy in the book said, "I've lost and gained an entire person in my lifetime." He realized that he's never going to be free of this desire, this urge to remake himself.

Isn't it a problem if you're always on a diet?
It's a weird thing. It's like a love-hate thing. You hate the fact you're depriving yourself. On the other hand, there is this good feeling of every day you look a little better. You step on the scale and you feel great. It's not necessarily some sort of evil thing to be on a diet.

We constantly see new diet books, like "21 Pounds in 21 Days." How is "Rethinking Thin" different?
This is a book that's going to help you understand why it is you've had so much trouble, why you aren't as skinny as you think you should be. It's to help you understand the biology. I don't think there is a perfect diet. I'm not going to tell you there's a perfect diet. But if you know what scientists know, you'll understand why you've done certain things and why it seems so incredibly easy for that weight to come back on. You'll understand what scientists know about how and why your brain and your genetics are controlling how fat you are and how thin you can become.

Is the bottom line that diets don't work?
They do work. You can lose weight. They can take you from the top of your [weight] range to the bottom. But you can't be necessarily as thin as you think you might want to be, just like you can't run as fast as you think you might want to run.  Everyone has their biological limits.