HealthDay News — Weight Watchers and Jenny Craig are the only two major commercial weight-loss programs marketed across the United States that can boast scientific evidence showing their clients maintain weight loss for at least a year, findings published in the Annals of Internal Medicine indicate.
“Primary-care providers need to know what programs have rigorous trials showing that they work, but they haven’t had much evidence to rely on,” says Kimberly Gudzune, MD, MPH, an assistant professor of medicine and a weight-loss specialist at the Johns Hopkins University School of Medicine said in a university press release.
To compare weight loss, adherence, and harms of commercial or proprietary weight-loss programs versus control/education or behavioral counseling among overweight and obese adult patients, the investigators culled data from 45 studies, 39 of which were randomized, controlled trials. The programs included Weight Watchers, Jenny Craig, Nutrisystem, Health Management Resources, Medifast, OPTIFAST, Atkins, The Biggest Loser Club, eDiets, Lose It!, and SlimFast.
Of those 11, only Weight Watchers and Jenny Craig had gone through studies showing that people not only lost weight but kept it off for at least a year, found the researchers. Weight Watchers helped participants sustain at least 2.6% greater weight loss at 12 months than people in a control group who just received information about healthy eating. Jenny Craig resulted in at least 4.9% greater weight loss after a year, compared with a control group provided nutrition education and counseling.
Another popular program, Nutrisystem, resulted in at least 3.8% greater weight loss than a control group. However, the available studies only followed up for three months and could not prove sustained weight loss, according to the report.
The study authors found that very low-calorie diets like Medifast, OPTIFAST, and Health Management Resources only appeared to provide short-term results. They also found mixed results for Internet or smartphone apps like The Biggest Loser Club, eDiets, or Lose It!, which they refer to as ‘self-directed plans’ alongside Slim-Fast and Atkins.