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Reliable Research Available on Very Few Commercial Weight Loss Programs

BALTIMORE – Just telling patients they need eat less and move more to lose weight rarely is effective. Physicians often need to make specific recommendations on where they can get help in taking off the pounds.

The problem is that relatively little evidence exists on the effectiveness of commercial weight-loss programs, according to a new study published recently in the Annals of Internal Medicine.

To help physicians navigate the effective of the programs, Johns Hopkins University School of Medicine researchers reviewed 4,200 studies on 32 major weight loss programs. They found that only 11 of the programs have undergone rigorous study, and only two of those programs – Weight Watchers and Jenny Craig — can prove scientifically that their participants, on average, lost more weight after one year than people dieting on their own, just getting printed health information, or simply receiving other forms of education and counseling sessions.

"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," said Kimberly Gudzune, MD, an assistant professor of medicine and a weight-loss specialist at Johns Hopkins. "Our review should give clinicians a better idea of what programs they might consider for their patients."

For the study, peer-reviewed articles from two major research literature databases and the weight-loss programs themselves were collected by researchers. Included were investigations that ran for 12 weeks or longer and were randomized controlled trials.

Because the majority of weight-loss programs have never been studied in randomized clinical trials, the researchers say, they ended up with 39 trials covering 11 programs. The programs fell into three categories:

  • High-intensity programs, such as Weight Watchers, Jenny Craig and Nutrisystem, which incorporate goal setting, self-monitoring, nutritional information and counseling;
  • Very-low-calorie meal replacement programs, such as HMR, Medifast and OPTIFAST; and
  • Self-directed programs, including Atkins, SlimFast, and the Internet-based Biggest Loser Club, eDiets and Lose It!

"Clinicians could consider referring patients who are overweight or obese to Weight Watchers or Jenny Craig,” the authors suggest. “Other popular programs, such as Nutrisystem, show promising weight-loss results, but additional studies evaluating long-term outcomes are needed.”

The study found that programs based on the Atkins diet — high in fat, low in carbohydrates — also helped people lose more weight at six months and 12 months than counseling alone, adding that the approach "appears promising.”