(RxWiki News) Many weight loss programs make big promises, but how many can live up to the hype long-term? Unfortunately, probably not too many.
That's the finding of a new study, anyway. Commercial weight loss programs are a growing market in the US — where around two-thirds of adults are overweight or obese, explained the authors of this new review, led by Kimberly A. Gudzune, MD, of the Johns Hopkins University School of Medicine.
"Primary care doctors need to know what programs have rigorous trials showing that they work, but they haven't had much evidence to rely on," Dr. Gudzune said in a news release.
Deborah Gordon, MD, a nutrition expert based in Ashland, OR, told dailyRx News that some doctors and patients are at the mercy of commercial weight loss programs because they lack detailed knowledge on nutrition and weight management.
"Obesity and its complications are not financial incentives but serious physiological conditions, even recently classified as 'illness,'" Dr. Gordon said. "For what other medical problem are physicians referring to commercial ventures?"
Dr. Gordon continued, "The programs for weight loss should be at the very least medically inspired if not completely medically directed. That said, it is of course important that physicians become educated about the strategies well-studied in modern medical literature ..."
Dr. Gudzune and team looked at 45 past studies ranging in length from 12 weeks to a year. These studies involved patients on a weight loss program compared to patients who were not involved in a program ("control" patients).
The studies covered 11 diet programs, such as Weight Watchers, Jenny Craig, Nutrisystem, Atkins, The Biggest Loser Club and eDiets. These programs all had a focus on nutrition alongside a social support or behavioral counseling aspect.
These researchers found that only two programs — Weight Watchers and Jenny Craig — had evidence of success helping patients keep weight off in the long term.
After a year, patients in Weight Watchers had at least a 2.6 percent greater weight loss than their control group counterparts. Patients in Jenny Craig had 4.9 percent greater weight loss than control patients after a year.
Some other programs showed success in the short-term, but there have not been long-term studies of their success. For instance, Nutrisystem patients had a weight loss of at least 3.8 percent more than the control group after three months.
Results for several other programs, such as Atkins and SlimFast, seemed mixed.
"We want people to experience the health benefits of weight loss — lower blood pressure, cholesterol and blood sugar, and lower risk of developing diseases like diabetes," said study author Jeanne M. Clark, MD, also of Johns Hopkins, in a press release. "Those benefits are long-term goals; losing weight for three months, then regaining it, has limited health benefits. That's why it's important to have studies that look at weight loss at 12 months and beyond."
In an editorial about this study, Christina C. Wee, MD, of Harvard Medical School in Boston, noted that despite the evidence of some success, none of the diet programs had stellar findings.
"It is unsurprising that highly structured programs with in-person social support, such as Weight Watchers and Jenny Craig, seem more effective in the long term than less structured interventions," Dr. Wee wrote. "Nevertheless, even with such programs, weight loss is modest and likely below patients' expectations"
Dr. Gudzune and team noted that further, long-term research is needed to better assess commercial weight loss programs.
The review and editorial were published April 6 in Annals of Internal Medicine. The National Heart, Lung, and Blood Institute funded this research. The authors disclosed no conflicts of interest.