WEDNESDAY, June 16, 2004 (HealthDayNews) -- New research suggests that the dieting habits of teenage girls offer a crystal ball into their futures. The news isn't good: Those who try the hardest to lose weight as adolescents are most likely to become obese adults.
The reason for the link isn't entirely clear. But it's possible that early dieting may disrupt the metabolism of teen girls, setting them up for obesity later in life, said study co-author Joanne Ikeda, co-director of the University of California, Berkeley's Center for Weight & Health.
"There's a subset of the population who are vulnerable to weight cycling, to yo-yo dieting," said Ikeda, a registered dietician. "I'm not saying every person who diets has a risk of weight 300, 400 or 500 pounds. But we really don't know how to identify that subset of the population that is at risk of gaining tremendous amounts of weight."
Ikeda and her colleagues surveyed 149 obese women from 2000 to 2001. All the participants had attended two annual conferences for large women, and all had a body mass index of 30 or higher, classifying them as having crossed from overweight to obese. Their mean BMI, a ratio of weight to height, was 46; some weighed more than 500 pounds.
The findings of the survey, which was co-sponsored by the National Association to Advance Fat Acceptance, appear in the June 2004 issue of the Journal of the American Dietetic Association.
The researchers found that women who started dieting before age 14 -- two thirds of all the women surveyed -- were more than twice as likely to have dieted more than 20 times compared to women who began dieting later.
More than eight in 10 of those who began dieting before age 14 said they were never able to maintain permanent weight loss.
It's not known how much the women weighed as teens, but Ikeda said most reported they weren't severely overweight at the time.
The study findings suggest that the obese women are no strangers to dieting, Ikeda said, rebutting the common perception that "fat people are lazy gluttons, that they're basically people who sit on the couch all the time and eat potato chips."
In fact, she said, "my experience has been that they have tried seriously repeated times to lose weight."
And what of the idea that dieting can lead to weight gain? There may be some truth to it, especially in diets that virtually starve people, said Julie Miller Jones, professor of nutrition and food science at the College of St. Catherine in Arden Hills, Minn.
"There is some thought that continuous dieting, particularly with rather severe caloric restriction, forces the metabolism to be more efficient -- to lose less energy as heat and capture more for fueling the body. And the net result is that it is harder to lose weight and keep it off," Jones said.
The problem, she added, is that fad diets often focus on quick weight loss, which requires great reductions in calories, instead of "the rather unpopular way to lose weight -- very slowly." Ideally, people shouldn't lose more than a pound of weight a week, she said.
Both Ikeda and Jones said teens who decide to diet must do so carefully and with an eye toward proper nutrition. In some cases, a diet may not be necessary at all.
"Rather than putting an adolescent on a diet, I'd like to sit down and talk about what they're eating and how they're spending their time," Ikeda said. "Forget about the diet business."
To learn more about proper weight loss, visit the National Women's Health Information Center.