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Pound for pound, it turns out that many popular weight-loss programs are not to diet for, a new study reveals.
Researchers reviewed 10 well-known programs and found there was not enough evidence to support the claims many of them make about helping people lose weight and keep it off except one.
Only Weight Watchers had strong documentation that its meetings-based, portion-control programs worked. One Weight Watchers study showed participants lost around 5 percent or 10 pounds of their initial weight in a six-month period and kept off about half of it over the next two years.
Still, the researchers at the University of Pennsylvania stressed that the lack of scientific evidence should not be seen as an attack on diet programs.
"There are no data on weight loss when you go to a health club, either," said Thomas Wadden, co-author of the study.
"We hope that doctors and patients will use this information to make more informed decisions."
He also urged weight-loss companies to conduct more strenuous research.
One of the high-profile plans examined was Jenny Craig, which emphasizes prepared meals and diet and exercise counseling.
Lisa Talamini, the company's chief nutritionist, said Jenny Craig will soon launch a large study based on Wadden's recommendations. But she cited a recent analysis by The Cooper Institute, a research group that focuses on exercise, that found Jenny Craig clients lost 15 percent, or an average of 22 pounds, of their initial body weight in a year.
The review's goal was to cut through the glossy ads and high-pitched testimonials of the programs' ads to discover the nuts and bolts: safety, qualifications of the staff, costs and effectiveness.
The study is published in an upcoming issue of Annals of Internal Medicine.
With Post Wire Services
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