Experts Assess What Works for Weight Loss

Weight loss programs that focus on changing behaviors, as well as those that combine behavior changes and weight-loss medications such as orlistat (Alli, Xenical), can help people shed pounds, according to a new review.

"We found behaviorally based weight loss programs are generally effective for weight loss," said Dr. Erin LeBlanc, an investigator for Kaiser Permanente Center for Health Research in Portland, Ore.

LeBlanc declined to mention particular behavioral intervention programs by name. However, components of commercial programs such as Weight Watchers, Jenny Craig and others include group support, encouragement of physical activity, setting of goals and other strategies.

The study is published in the Oct. 4 issue of theAnnals of Internal Medicine.

LeBlanc and her colleagues were asked by the U.S. Preventive Services Task Force (USPSTF) -- a federal government panel that routinely issues guidelines on various medical issues -- to look at evidence on the effectiveness of various weight loss interventions. In 2003, the USPSTF recommended that doctors screen all adults forobesity and offer behavioral interventions for those who are obese -- people with a body mass index (BMI) of 30 or above.

The USPSTF hopes to update those recommendations, so it asked LeBlanc's group to revisit the issue, looking over the newest data.

In all, the team reviewed 58 published trials involving overweight adults. Some had received behavioral treatment only, while some got behavioral treatment plus weight-loss medication.

Use of behavior-based weight loss programs resulted in people dropping an average 6.6 more pounds over 12 to 18 months than if they had attempted to slim down without such programs, the researchers reported. People who went to 12 to 26 intervention sessions during the first year on such programs lost 9 to 15 pounds, whereas those in the comparison groups lost little or no weight.

After 12 months, those who used the weight-loss drug orlistat along with a behavioral weight-loss program lost 11 to 22 pounds on average (about 8 percent of their starting weight). In comparison, people who had taken a placebo while they were on a weight loss program lost an average of between 7 and 13 pounds, the researchers said.

Research on the diabetes drug metformin -- used off-label for weight loss -- is limited, LeBlanc's team said. Two studies evaluated by the researchers included people with so-called "prediabetes." Those who took metformin and engaged in a behavioral weight-loss program lost about 4 to 9 pounds, on average, compared to a loss of less than 2 pounds in those who just had behavioral support.

A typical behavior-based program studied had multiple parts, LeBlanc said. For instance, a program might offer group education sessions, individual counseling, or a combination, and also encourage physical activity. These programs would also encourage participants to monitor themselves and set goals.

LeBlanc's team encountered some trouble evaluating the data, especially regarding the medication studies, which typically had high dropout rates (often because of gastrointestinal symptoms). These studies often didn't include enough participants to accurately assess side effects, either, the researchers said.

And while those people who took orlistat typically experienced more weight loss, "we don't know what happens when they quit [the drug]," LeBlanc noted.

The FDA revised the warning label for orlistat in 2010, alerting users to a rare but severe risk for liver injury. The label revision applied to both Alli, sold over the counter, and Xenical, the prescription form.

"Our evidence says that the benefits of weight loss drugs have to be weighed against the risks," LeBlanc said.

Dr. Frank Greenway, professor and chief of the outpatient clinic at the Pennington Biomedical Research Center in Baton Rouge, La., called the weight-loss results "underwhelming."

While a small percent of people may take weight off short term, few keep it off long term, he said.

Another expert agreed. The new study "confirms what we knew," said Dr. Robin Blackstone, president of the American Society for Metabolic & Bariatric Surgery and a bariatric surgeon in Scottsdale. "Medical weight loss is not very robust, but it [diet medication] does have an effect."

The bariatric surgery community, she said, is supportive of people trying behavioral and medical interventions first, before they head to surgery. For some, she said, surgery may eventually be a more effective option. "I think evidence is beginning to show that there are people with a very high propensity to being big," she said. "They're fighting against that their whole life."

Blackstone reports consulting work for Johnson & Johnson. She is conducting a research study for EnteroMedics, which is developing an obesity treatment.