Cover Story

For men and women waging a lifelong battle with the scales, the power of the group wields significant leverage, at least in the short term. Working in groups, people can exchange diet and exercise tips, provide support, even go walking or dine out together.

Studies have demonstrated that a variety of group treatment settings--from intensive closed groups in a university clinic to more informal commercial-style programs like Weight Watchers--can help people achieve at least some weight loss and can prove more effective than dieting alone.

"Groups really provide patients a sense of universality--that they have a problem that other people share," says longtime obesity researcher Thomas Wadden, PhD, a psychology professor at the University of Pennsylvania School of Medicine and director of the university's Weight and Eating Disorders Program. "There is a sense of group support. People provide suggestions for each other."

Backing up that idea are findings from a study published in 2001 in the Journal of Consulting and Clinical Psychology (Vol. 69, No. 4). The study indicates that groups can achieve better results than one-on-one interventions. Even when the study participants preferred individual treatment, they did slightly better in group settings, losing 11 percent of their weight compared with 9 percent for individuals.

Psychologist Michael Perri, PhD, a professor of clinical and health psychology at the University of Florida and one of the study's authors, is quick to point out that while the four-pound difference in weight loss wasn't clinically significant, the study does demonstrate that the more economical group approach can be used effectively for most people.

Group treatment results vary. But typically overweight people can count on losing about 10 percent of their body weight in six months, says Rena Wing, PhD, professor of psychiatry at Brown Medical School. Numerous challenges remain, though. Some people, for example, may also need individual treatment to address emotional triggers for their weight gain, she says.

The biggest challenge, however--and one that's still unresolved--is how to prevent all-too-common weight gain after group treatment ends.

Seeking the most effective group design

In investigating group treatment's long-term effectiveness, researchers turned their microscope on Weight Watchers last April. A study published in the Journal of the American Medical Association (Vol. 289, No. 14) assessed the effectiveness of the program versus a largely self-help approach in which weight loss counseling was limited to printed materials and two 20-minute sessions with a dietitian. The study, which tracked 423 overweight and obese people, found that the commercial group's mean weight loss was greater--9.5 pounds versus 3 pounds in self-help--during the first year. Both groups, though, lost ground by the end of the second year, with the commercial group's participants holding onto a 6.4-pound loss overall and the self-help group members returning to their pre-study weight.

Commercial programs like Weight Watchers and smaller behavioral weight-loss groups often have similar approaches, using support and discussion about exercise and good diet as well as assignments, such as keeping a daily food diary.

Smaller behavioral weight-loss groups, which usually enroll fewer than 25 people, may be based at universities or medical centers and run for a set number of weeks, says Terry Wilson, PhD, the Oscar K. Buros Professor of Psychology at Rutgers University. They may be run by a variety of weight-loss professionals, including a nutritionist or psychologist, he says. Some larger commercial programs, such as Weight Watchers, don't limit enrollment time, and people can drop out and later rejoin.

Clinic-based behavioral groups are likely to result in better weight loss than commercial-style programs because of the individualized attention, claims Wadden. But there have been no comparative studies to prove that, he notes, nor have there been any research results on what size group works best.

For the most part, group size is set according to the preferences of treatment professionals. Wadden, for example, says he prefers to limit his groups to eight to 10 people. He does this, he says, "to ensure that everyone gets an opportunity to speak." He notes, however, that researchers have shown that larger groups of 15 to 20 people have achieved equally effective weight-loss results.

But at what point is group treatment no longer statistically effective--and when does staying in the treatment long term become prohibitive in today's busy world?

"We know that ongoing contact helps people, but it's hard for people to come every week for the rest of their lives," says Wing of Brown Medical School.

And studies indicate that weight loss slows as treatment continues. One 1989 study published in the Journal of Consulting and Clinical Psychology (Vol. 57, No. 3) by Perri found that people attending groups for 40 weeks did better than their counterparts who got help for only 20. But in the second 20 weeks, the average weekly weight loss slowed from 1.2 pounds to less than half a pound.

"You probably reach maximum benefit somewhere around a year," Perri says. Even after six months, as weight loss levels off, a group's commitment shifts significantly, Wadden says. Some participants are still dieting while others start bingeing, Wadden explains, adding: "That's when you lose the homogeneity--the unity of purpose."

But the search is on to keep such breakdowns from occurring, and some programs show promise. One rigorous group treatment approach, the Trevose Behavior Modification Program, has attracted significant attention because it achieves weight-loss results that surpass the typical 10 percent and appears to largely sustain those results over several years.

Adherents to the strict weight-loss regimen lost an average of 19 percent of their weight, equivalent to about 40 pounds, after two years and didn't regain much, remaining 17 percent under their initial weight after five years. The study, which followed 171 obese men and women, was published in the International Journal of Obesity (Vol. 24, No. 7)

The program was launched in 1970 by a formerly obese patient, in conjunction with an obesity researcher. It's free and entirely run by volunteers. Enrollees meet weekly in groups of eight to 12. Participants are required to attend each session and meet all of their predetermined weight-loss goals. Persistent backsliders are kicked out.

Perhaps because of its mandatory meetings and other rigorous standards, Trevose's attrition is significant, according to the obesity journal study. After two years, just under half remained; by comparison, the Weight Watchers study still enrolled nearly three-fourths.

Trevose has its detractors. One criticism is that the program's tough-love approach turns away people seeking help, if they falter. For example, psychologist Janet Latner, PhD, assistant professor at the University of Canterbury in New Zealand and the 2000 study's lead author, says that the program's strict rules could potentially and incorrectly turn away "people who have the ability to go on and eventually succeed." But, she stresses, "I think they also have the positive effect of having people stay on track when they would otherwise stray."

Keeping the pounds off after treatment

Researchers are still wrestling with how to extend the effectiveness of group treatment after it ends.

Incorporating friends and family in group treatment may help, Wing says. In a 1999 study with University of Minnesota psychologist Robert Jeffery, PhD, Wing tracked 166 people interested in weight loss. Two-thirds of the participants who enrolled with friends and were given social support in addition to standard behavioral treatment were able to sustain their weight loss six months after meetings ended. By comparison, only one-fourth of those who attended alone and didn't have the social support achieved the same success, according to the Journal of Consulting and Clinical Psychology (Vol. 67, No. 1) study.

More research is needed, says Wing, cautioning that the study's participants were allowed to choose whether to enroll with loved ones. Wing also is involved in ongoing research examining how group support over the Internet compares with other methods, including group face-to-face therapy, in maintaining weight loss.

Another helpful strategy might be to ensure that people's expectations are more reasonable, says Wilson. He cites interesting work by Oxford University psychiatry professor Christopher Fairburn, MD, delving into the role of self-acceptance in weight loss.

"Many of these individuals would like to lose much more than the 10 percent," Wilson says. "Then, the argument goes, they aren't really satisfied because they don't look dramatically different." But psychologists can intervene periodically, including after the first 10 percent is lost, emphasizing the lifestyle and longevity benefits they've already gained, Wilson says, noting that, "A 10 percent weight loss makes a big difference in terms of your health."

Still, how much can human optimism be stunted? Wadden is not encouraging. In a study published in the December 2003 Journal of Consulting and Clinical Psychology (Vol. 71, No. 6), he describes the split between education and perception.

The 53 obese women studied were assigned to a variety of weight-loss treatments, including group treatment, and warned repeatedly in writing and verbally that they could only expect to lose 5 to 15 percent of their weight. Yet, they only modified their expectations somewhat, predicting they'd lose 25 percent--rather than their initial, and for most of them unrealistic, goal of 28 percent weight loss.

However, even dashed expectations and a fluctuating weight-loss pattern beat the alternative, Wadden says.

"I think it's far better to have lost and regained rather than to never have lost at all," he explains. "You may have prevented your continual weight gain."

Charlotte Huff is a writer in Fort Worth, Texas.