Commercial weight-loss programs sell diet plans, as well as prepared foods and diet aids to go along with those plans. They also hold regular meetings to provide encouragement and support for people who are trying to lose weight.
In a bid to help physicians guide obese and overweight patients who want to try a commercial weight-loss program, researchers studied the effectiveness of these programs and found that only 11 of the 32 major commercial weight-loss programs met the scientific gold standard of reliability. They also found that only 'Jenny Craig' and 'Weight Watchers' were backed by clinical trials that lasted 12 months or longer and showed program participants had a greater weight loss than nonparticipants.
Researchers at Johns Hopkins reviewed 4,200 studies for solid evidence of their effectiveness in the long-term. They found that of the 32 major commercial weight-loss programs marketed nationwide, only 11 have been rigorously studied in randomized controlled trials. The investigators also found that from these studies, only two programs, Jenny Craig and Weight Watchers, are supported by gold-standard data showing that participants, on average, lost more weight after one year in these programs than people who were either dieting on their own, got printed health information, or received other forms of education and counseling sessions.
Participants in the very-low-calorie meal replacement programs were seen to have lost more weight than nonparticipants in trials lasting from four to six months. However, the authors found only one long-term study, which showed no benefit from such a program at 12 months. The researchers noted that very-low-calorie programs also carry higher risks of complications, such as gallstones.
The study authors said, "Results in those programs were generally modest, with participants losing on average between 3 and 5% more than the studies' control groups of non-program participants. NutriSystem also produced more weight loss at three months than counseling or education alone, but we were unable to find any long-term trials of that program. 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. The approach appears promising. No definite conclusions could be made about Slim-Fast and the Internet-based programs."
The study appears in the Annals of Internal Medicine.