Out of all the commercial weight-loss programs available, only Jenny Craig and Weight Watchers have enough evidence to support their claims that they help people lose weight and keep it off, new research indicates.
The study was published in the April 7 issue of the Annals of Internal Medicine.
“There have been recent changes in healthcare policy that may encourage healthcare providers to start screening their patients for obesity, so I think it’s critical to have a weight-management plan if obesity is identified,” Kimberly Gudzune MD, MPH, from Johns Hopkins University School of Medicine, Baltimore, Maryland, told Medscape Medical News.
“And we found that not only did Jenny Craig and Weight Watchers help people lose weight, but they’ve done the longer-term studies going out to 12 months and beyond to show that people keep the weight off, which is the most important idea here from a medical perspective: we’re interested in that sustained weight loss as the end goal.”
Most of the commercial weight-loss programs have not been studied in randomized clinical trials (RCTs).
However, the investigators were able to identify 39 RCTs evaluating 11 weight-loss programs for their analysis.
Results showed that Jenny Craig produced at least a 4.9% greater weight loss at 12 months, compared with people who diet on their own, who rely on printed health information, or who receive other forms of education or counseling sessions, the authors report.
Weight Watchers was next, resulting in at least a 2.6% greater weight loss at 12 months compared with controls in an intention-to-treat analysis.
Nutrisystem also produced “promising” weight-loss results at a 3.8% greater weight loss at 3 months than control groups. However, the authors note that longer-term outcomes are needed to ascertain whether Nutrisystem leads to sustained weight loss.
In an analysis of very-low-calorie programs, investigators found that Health Management Resources (HMR), Medifast, and Optifast resulted in at least a 4.0% greater short-term weight loss than counseling. However, some attenuation of the weight-loss effect occurred beyond 6 months when such data were reported.
Very-low-calorie programs also carry a higher risk of complication such as gallstones, Dr Gudzune and colleagues said.
The Atkins diet also led to larger weight losses than control groups in the short term but by 12 months resulted in only a 0.1% to 2.9% greater weight loss than counseling.
Results from trials evaluating SlimFast were mixed, investigators add.
Investigators also evaluated Internet-based programs, including The Biggest Loser Club, eDiets, and Lose It! but found that results from three RCTs evaluating these programs suggested they were ineffective.
“In my own clinical practice, patients come in with the idea that a diet or a weight-loss program is something that you do temporarily and then once they lose the weight, they can go back to their ‘regular’ lifestyle,” Dr Gudzune said.
“I think what we really need to advocate for is a real change in lifestyle because the things that we do to lose weight are similar to what we need to do to keep the weight off, and people really need to be ready to make those changes….It takes time to dedicate yourself to a weight-loss program and reorganize your life to make it a success.”
Highly Structured Programs
In an accompanying editorial, Christina Wee, MD, MPH, from Beth Israel Deaconess Medical Center, Boston, Massachusetts, said it was not terribly surprising that highly structured programs with in-person social support, such as Jenny Craig and Weight Watchers, seem to be more effective in the long term than less structured interventions.
“Nevertheless,” she writes, “even with such programs, weight loss is modest and likely below patients’ expectations.”
For example, Dr Wee cites one study in which obese patients believed that they would need to lose an average of 11% of their initial weight to derive any health benefits from the weight loss.
“Unrealistic expectations may affect patients’ willingness to adhere to and pay for these programs,” she observes.
“Physicians can potentially important role [in helping patients lose weight] by making the link between modest weight loss and health benefits.”
Recent guidelines advocate that people lose 3% to 5% of their starting body weight and then to try to keep that off as their first weight-loss goal.
The authors and Dr Wee have reported no relevant financial relationships.
Ann Intern Med. 2015;162:501-512, 522-523. Abstract, Editorial