The study was funded by Weight Watchers but run by independent researchers led by Susan A. Jebb, PhD, of the U.K. Medical Research Council.
The study enrolled 772 overweight or moderately obese adults. They were randomly assigned to two groups. Half got their nation's standard-of-care weight loss advice from their primary care provider. The other half were sent to Weight Watchers. Neither group had to pay for their treatment.
Weight loss studies are notorious for the number of people who drop out before the study is over. Usually, this is because people fail to lose weight and give up. In the current study 61% of those assigned to Weight Watchers completed 12 months of the program. So did 54% of those assigned to standard care.
What happened? Weight Watchers won:
- Among patients who completed the year-long program, those in Weight Watchers lost nearly 15 pounds -- about 7 pounds more than those who completed a year of standard care.
- Those who completed a year of the Weight Watchers program were three times as likely to lose 5% of their body weight -- and 3.5 times more likely to lose 10% -- than those who completed a year of standard care.
- Among all patients measured from the time they started until the time they dropped out or finished the program, those assigned to Weight Watchers lost about 9 pounds -- about 5 pounds more than those assigned to standard care. They were three times more likely to lose 5% or 10% of their body weight.
What Is the Best Weight Loss Program?
Jebb and colleagues note that various commercial weight loss programs have been shown in clinical studies to help people lose weight.
"These studies suggest that other commercial providers, working in partnership with primary care providers, could also offer effective treatment options, but these programs need to be assessed in the primary care context," they note.
Nevertheless, the researchers praise several aspects of the Weight Watchers program:
"What really matters is our holistic approach in terms of providing a supportive environment for healthy eating behavior, cognitive skills, and physical activity," Weight Watchers' Chief Scientific Officer Karen Miller-Kovach, RD, tells WebMD.
It remains to be seen whether nations can cut their obesity-related health care costs by underwriting Weight Watchers and other commercial weight loss programs. But an editorial accompanying the Jebb study notes that the U.K. health service already pays for commercial programs in most of England.
"Such programs are likely to be an important component of the medical management of obesity in primary care," conclude editorialists Kate Jolly and Paul Aveyard of the University of Birmingham, U.K.
In the U.S., Miller-Kovach says, Weight Watchers costs about $40 a month. For those who achieve their weight loss goals, a monthly weigh-in and checkup is free.
The Jebb study, and the Jolly/Aveyard editorial, appear in the Sept. 8 online issue of The Lancet.