Jenny Craig reigns queen of popular diets, according to a new report from Consumer Reports Health.
Researchers based the overall scores on adherence to the 2010 U.S. Dietary Guidelines and results of published randomized clinical studies that analyzed the short- and long-term weight loss and drop-out rates of seven popular diets.
"The biggest surprise was that the diet that came out on top came out on top by a lot," said Nancy Metcalfe, senior program editor of Consumer Reports Health.
Jenny Craig topped the list with 85 points. Slim-Fast came in second with 63 points and Weight Watchers, a popular diet for many Americans, came in third with 57 points; a ranking that surprised some nutritionists.
NutriSystem did not receive an overall score because there were not enough published clinical trials that documented its weight-loss results.
"Weight Watchers got dinged on sodium," Metcalfe said. "While the diet is probably the most flexible with the most intense support and a lot of support for exercise, they need to pay more attention to sodium."
Metcalfe said Weight Watchers encourages its dieters to eat soups that will fill them up, but many soups come with a heavy dose of salt, which often exceed the recommended U.S. Dietary Guidelines.
Weight Watchers revealed a new system last year called PointsPlus. The company completed a clinical trial to analyze the new points system but the results have yet to be published, which, Metcalfe said, also might have affected the report's results.
Metcalfe said a 332-person study that was published in the Journal of the American Medical Association in October helped Jenny Craig win the title. The study found that 92 percent of its participants stuck with the Jenny Craig program during the two-year study period and the dieters weighed an average of 8 percent less than when they began the program.
"We were pleased to be rated as Consumer Reports' best-rated diet," Jenny Craig CEO Patti Larchet said in a statement. "This news confirms what we have always known: that Jenny Craig's clinically proven, comprehensive approach to weight management works."
In an emailed statement, Weight Watchers defended its regimen and criticized Consumer Reports Health's interpretation of a 2009 study, published in the Journal of the American Medical Association, that pointed out the effectiveness of the Jenny Craig approach.
"We are disappointed that some key points in the JAMA study used prominently by Consumer Reports in their evaluation of the Jenny Craig program were left unsaid," the statement read. "The JAMA study ... was done to see what happens if you provide people with free food -- valued at $6,000 over the two years -- and other perks on their ability to lose weight. This is hardly the real-life scenario that a consumer faces when choosing a weight-loss method."
The Jenny Craig diet offers its own brand of food, including single-serving entrees, snacks and desserts, which are sent to the dieters' homes. Prices vary, but the cost of the food can range between $400 and $600 per month. The company also offers weekly counseling sessions in-person or by phone.
"There's something about this diet that works for a lot of people," Metcalfe of Consumer Reports Health said. "Of course, the best diet for you is the one you can stay on. Jenny Craig is certainly a lot less work than preparing your own food that is portion controlled."
Dr. Christina Scirica, faculty member at Harvard Medical School, said it is likely that Jenny Craig's individualized approach to diet and counseling allows for so much weight-loss success.
"Considering the features of each program, I am not surprised that Jenny Craig took the lead," Scirica said. "Of the programs studied, Jenny Craig addresses more of the factors that contribute to diet failures than the other programs do."
She added, however, that it's important to clarify long-term outcomes.
"I suspect that the one-on-one coaching sessions are particularly instrumental in helping people stick to their weight loss while in the program," Scirica said. "Presumably, however, people do not stay in the program indefinitely and, although the Jenny Craig program reportedly teaches them the skills needed to maintain their weight loss after leaving, one cannot say from this study whether those efforts actually work."
Dr. David Katz, director of the Prevention Research Center at the Yale University School of Medicine, agreed.