Book chat: Diets, science and the appetite for hope

Peter Mucha: Hello, fellow weight watchers. OK, maybe you don't want to admit it. But most of us at some time or another have tried to shed some pounds. I'm pleased to be joined today by Gina Kolata, whose book Rethinking Thin is a real eye-opener. And has a local angle. It focuses largely on a research study done by Penn. Could you tell us about the study, Gina, and how you came to write the book?

Gina Kolata: The study was a national one, funded by the federal government, and asking which diet is better for weight loss and health -- Atkins or low calorie? One of the three medical centers that participated was the University of Pennsylvania. I thought this gave me a perfect opportunity to write a book asking what medical researchers have learned about weight loss and what the popular impressions are. And by following some of the people who took part in the study at Penn I could see, in real life, how these diets worked and what it was like to try for two years to finally, for once and for all, get thin.

Peter Mucha: Now has the study finally been published?

Gina Kolata: No. It's still going on. The subjects enter the study in waves -- I followed two groups who spent two years in the study, but when they finished, in the spring of 2006, another group was just starting. It will be another year before that group, the last one, I believe, is finished. Then the data have to be analyzed and published, so we're talking several years now. But it was pretty clear from what I saw that there's no magic in either diet.

Peter Mucha: But both worked for a while. You really follow some participants, show they really tried and lost weight for a while. Then you weave in research that shows that it's not lack of effort, or stupid choices, or lack of willpower that ultimately results in the pounds returning. As people lose weight, their metabolism slows, as if the body resists the whole effort?

Gina Kolata: It was what one man in the study called "a fascinating two years, an almost transforming two years." The participants tried really hard and they lost a lot of weight in the first year. Then, although they desperately wanted to be thin, the weight crept back, just as the scientific studies over the years predicted. But the participants said they were changed people and had come to understand themselves and the limits of their ability to be arbitrarily thin. One man, Carmen Pirollo, said, "There are those moments when you say, 'I couldn't go on another diet now for love or money.' And then there are those times when you say, 'Now's the time, I'm going to do it again.' I probably will be one of those people who diet for the rest of their lives. Or let's not call it dieting. Let's call it monitoring. I will be monitoring my weight for the rest of my life.'"

Peter Mucha: So maybe there's a saving grace ... but all these people had such high hopes ... weren't satisfied with just losing 10 percent early on. So what's the answer? Exercise? Or do we have to wait for magic pills?

Gina Kolata: I think the answer is not to beat yourself up if you try and try and can never reach the weight goals that society holds up to you. And the message for thin people is to give fat people a break. Just like I can't run a 5-minute mile no matter how much I train -- I have a biological limit to how fast I can run -- different people have different biological limits to how thin they can be. It's not a matter of trying harder.

Peter Mucha: It was interesting how you document that society has gotten LESS accepting of a little chubbiness. At the turn of the century, the ideal beauty was a woman who was normal, or even pudgy not skinny. And yet we think we're so much more tolerant today.

Gina Kolata: My favorite example is the Miss America contest winners. In the 1920s the winners had body mass indexes that ranged from 20 to 25. For example, a woman who is five feet tall and weighs 120 pounds has a BMI of 20. More recently, the winners had BMIs as low as 16.9. That same woman with a BMI of 16.9 would weigh just 101 1/2 pounds!

Peter Mucha: You've also written a book on fitness, though. Even if we're genetically predisposed to a particular weight, we can do things to improve our health and fitness, right? That should be the goal?

Gina Kolata: When people asked me which exercise is best I always said you should start by asking what is your goal? The same is true for weight loss. If better health is your goal, you may not have to lose as much or you may not have to lose anything at all. But many would agree with Carmen in my book who said the pressure he feels is to look good, which means thin.

Peter Mucha: One study in the book amazed me. Someone did a reverse diet study, trying to get healthy men to gain weight -- and they had trouble! The more they ate, the more their bodies revved things up, until they were eating like 10,000 calories a day!

Gina Kolata: I was amazed too. It turns out that it is just as hard to get your weight above your biological limit (a weight range that can span 20 or 30 pounds) as to get it below. The men's metabolisms increased by about 25 percent and food became absolutely unappealing to them. When the study ended they effortlessly returned to their original weights. Anna: To Ms. Kolata: Where you stand on the question of whether dieting is a worthwhile thing AT ALL? After having tried dieting in my foolish youth, and watched so many people spending endless mental energy on dieting, I am absolutely convinced it is not. Would like your thoughts. I've read some of your columns in the New York Times, and I must admit I was a bit dismayed to see what looks like ANOTHER book about diets. Will this country ever end this obsession?

Gina Kolata: To Anna: My book is NOT a diet book and I do not come out in favor of diets. But I also think that neither you nor I can change society overnight and there is so much pressure on people to be thin that many will diet anyway. I hope my book will allow them to understand themselves and to understand why getting thin is not so easy, or even possible, for many people.

Peter Mucha: That's what I really appreciated about your book, Gina. Wasn't another faddish approach, peddling false hope. You really put a lot of effort into documenting all the studies that frustrated researchers, like Penn's Albert Stunkard, have done to try to unravel the diet puzzle. It makes for fascinating reading.

Gina Kolata: Thanks, Peter. I think the last thing the world needs is another diet book. But what interested me was the disconnect between what scientists knew about weight control and what the public is being told.

Peter Mucha: You know, an Atkins-like diet once worked for me. For six months. Lost 30 pounds. Then there this party and this plate of brownies ... But I digress ... Let's wrap this up by telling people about your being at the Free Library on Thursday night.

Gina Kolata: Thanks, Peter. I will be talking about my book and answering questions from 7 to 8 p.m. And the book will be sold there, too. I'm looking forward to it -- I've heard the Free Library holds great events. It's been fun chatting today.

Peter Mucha: While we were chatting, three colleagues came by asking to borrow the book! Thanks for joining us, Gina.

Gina Kolata: I hope they like it. It's been a pleasure, Peter.