Stop Dieting!

By Amanda Spake | Jan 16, 2006 | 2502 words, 0 images

It's diet season, that time of year when more than 76 million Americans resolve to never eat another french fry, swear off sweets, stop swilling beer, and pray for a magic pill to shorten the days of diet deprivation that so often mark the new year. The call is everywhere. Good Morning America is featuring weight-loss tips every day this month. AOL tells its subscribers via E-mail that it's "Time to lose your spare tire." NBC last week rolled out a special edition of its obesity reality show, the Biggest Loser. Magazines lining grocery aisles exhort you to "Lose 10 pounds this month!"

But can you lose 10 pounds in a month and keep it off? Americans spend more than $33 billion a year on diet books, foods, programs, gadgets, and DVD s in the hopes of losing weight. Yet, after decades of dieting, about two thirds of the American population remains overweight. Some 30 percent are obese, and more than half of them are dieting. Which raises the question: Does dieting work? Do people lose weight permanently on diets? Does dieting lead to better health?

Nutritionists, exercise physiologists, and other health professionals are asking these questions with increasing frequency. And a small but growing number of them believe that the solution is simple: Stop dieting. Stop obsessing about every morsel you put in your mouth, stop weighing yourself twice a day, stop letting the quest to be thin control your life. "I'm almost convinced that dieting is totally useless," says Cris Slentz, an exercise physiologist at Duke University Medical Center. "It's the physical activity aspect of our lifestyle that is the main culprit in our overweight problems. Most of us are eating 25 to 100 calories a day too many, and gaining 10 pounds or less per year. Our appetite system really works pretty well. So why would we use a 1,000 calorie per day deficit diet to try to correct the weight imbalance? It's nuts, and it isn't leading to long-term healthy weights." Steven Hawks, a professor of health science at Brigham Young University, agrees. "You would be hard pressed to review the dietary literature," he says, "and conclude that you can give people a set of dietary guidelines or restrictions that they will be able to follow in the long term and manage their weight successfully."

Slentz, Hawks, and other researchers note that most studies show that the vast majority of people can't stick with a diet very long. Though some dieters do make lifestyle changes that lead to permanent weight loss and better health, most regain much, if not all, of their lost weight in three to five years. Results reported last week from the federally funded Women's Health Initiative do little to enhance dieting's reputation. After seven years, women on a low-fat diet maintained a mere pound of their initial loss. And some studies show that frequent dieters actually gain weight.

Yet, dieting to achieve weight loss has been a cornerstone of obesity treatment, because excess weight is associated with high blood pressure, unhealthy cholesterol levels, metabolic syndrome, and other cardiovascular risks and increases the likelihood of developing type 2 diabetes and some cancers. But stop-dieting advocates point out that many other factors also contribute to these conditions: age, family history, gender, diet quality, stress, socioeconomic status, vitamins, and minerals--and some of these causes are more significant than weight.

While losing modest amounts of weight often lessens the impact of such health problems, so do regular exercise and healthful eating. "Even in heart disease, the role of fat tissue itself is small compared to the role of diet and exercise," says Linda Bacon, a nutrition professor at the University of California-Davis. "Since diet and exercise is the stuff that really matters, let's go after it directly and not use weight loss as the goal."

Fitness counts. Obesity, defined as a body mass index (a measure of height versus weight) over 30, does seem to increase mortality, but a study published last year in the Journal of the American Medical Association by the Centers for Disease Control and Prevention showed that increased deaths linked to obesity occur largely among those with BMI s over 35--people who carry an extra 50 or more pounds. The study revealed that Americans who are merely overweight--with BMI s between 25 and 30--actually live longer than people of normal weight. This may be due in part, the authors suggest, because new drugs to treat hypertension and cholesterol have reduced the negative impact of weight.

For years, research by Steven Blair, CEO of the Cooper Institute in Dallas, has shown that men and women who achieve a high level of fitness, regardless of weight, live longer and develop fewer chronic illnesses than thin people who aren't fit. It's also not clear that weight loss can make a heavy person's body the same as the body of a person who is naturally thin. Research on the role fat cells play and the impact of genes on weight gain, in fact, indicate that overweight bodies are never the same as naturally thin ones--no matter how much weight people lose.

Nevertheless, diets sell books, attract media attention, and fatten the wallets of authors who write them far more than they slim the bodies of the people who try them. Most popular diets seem to produce about the same modest weight loss. A study last year in JAMA looked at four such diets: Atkins (low carb), Ornish (low fat), Weight Watchers (low calorie), and the Zone (low glycemic load). Participants were randomly assigned to each diet. Only 50 to 65 percent of dieters stuck with the plans long enough to lose weight. But the ones who did lost between 4.6 and 7.3 pounds in a year and improved some of their cardiac risk factors, such as cholesterol levels. Michael Dansinger, an endocrinologist at the Tufts-New England Medical Center and lead researcher of the trial, calls the results "underwhelming." For her part, Karen Miller Kovach, chief scientific adviser for Weight Watchers, says "Weight Watchers has never preached diet alone as a means to lasting weight loss. But diet is part of the comprehensive lifestyle program."

Many experts were anxiously awaiting the first chapter in the Women's Health Initiative dietary modification study, probably the largest trial of a low-fat diet ever done, which was reported last week in the same journal. It showed that among more than 19,000 post-menopausal women, a low-fat, high-carbohydrate diet does not cause weight gain, as some low-carb enthusiasts have claimed. But it resulted in little long-term weight loss, either. Women in the study lost about 5 pounds the first year and kept off only about 1 pound over the seven years of the study.