The Science of Slimming
Getting rid of all those unwanted pounds is as simple as calories in, calories out. It's also as mysterious and complex as the workings of the human mind
Next, she eliminated fast foods and much of the sugar and fat from her diet. She also reduced portion sizes and started lifting weights and walking everywhere. She has now lost 65 pounds, but it has taken her 11 years. At 165 pounds, Johnson isn't thin, but she is fit. She works out twice a day, doesn't drink caffeine, and allows herself beer or wine only on weekends and special occasions. (Studies show that wine, especially, is associated with eating more.) Now that she has maintained her reduced weight for five years, she is among the 3,000 "successful losers" who make up the National Weight Control Registry, the largest collection of weight-loss success stories in the world (http://www.lifespan.org/ Services/BMed/Wt_loss/NWCR/de fault.htm). Using data drawn from the registry, scientists hope to identify how to achieve long-term weight control. "Virtually all of the people in the registry had tried to lose weight before, often many times, and had either regained it or failed to lose," says Rena Wing, a professor of psychiatry at Brown University and a registry founder. "So the same people who are now successful were previously unsuccessful, and that's an important message: Keep trying."
Strategies. Successful losers always mention behavioral strategies such as keeping a food journal, weighing often, eating breakfast to reduce late-day hunger, and exercising religiously--about 60 to 80 minutes a day. Three in four walk regularly, and nearly all eat a low-calorie, low-fat diet--about 24 percent fat. "Nobody," says Wing, "is maintaining their weight loss with a diet low in carbohydrates."
Indeed, the great diet debate--Atkins or Ornish or something else--is unhelpful, researchers say. "People have this horse-race mentality," says Brownell. "As if you line all the diets up, and ring the bell, one of them will cross the finish line first." Stanford University professor Christopher Gardner has set up just this sort of head-to-head competition. In a trial with 300 women over three years, Gardner is testing the Atkins diet, the Zone diet, the Ornish diet, and Brownell's own low-calorie program. His study will evaluate the number of pounds lost on each, as well as changes in blood pressure, insulin, cholesterol profiles, percentage of body fat, appetite, food preferences, and more. The essential problem with diets, Gardner says, is that people don't stay on them long. The average weight-loss attempt is four weeks for women, six for men. "So until you pick something that's going to last all your life," he adds, "you haven't found the `right' diet."
And in the end, there may be no "right" diet. Michael Hamilton, former medical director of the Duke Diet and Fitness Center, the Pritikin Longevity Center, and now a researcher at the Pennington Biomedical Research Center at Louisiana State University, says food is not the key to weight control anyway; exercise is. "And we have to struggle to get enough physical activity nowadays," Hamilton adds. A study released last month by the CDC shows just how great that struggle has become. About half of U.S. adults say they walk during their usual daily activities. More than a third primarily sit. And less than a third engage in any regular leisure-time physical activity.
"The important research to be done now," says Brownell, "is not to find the best weight-loss diet, but to find the factors that make different weight-control programs work for different people. It doesn't matter what's popular, or what your neighbor did, or what you saw on TV. It matters what works for you."
advertisement
