If you are trying to lose some weight, your best bets for commercial weight-loss plans appear to be Jenny Craig and Weight Watchers. A review of randomized control trials of several commercial diet programs found that Jenny Craig and Weight Watchers were the most effective at helping members lose a meaningful amount of weight and keep it off for a year.
The review looked at 45 studies of 11 commercial weight-loss programs and compared the results for effectiveness, how well people stuck with the program, and any harms. The studies included in the review often compared plans to educational programs or behavioral counseling.
The researchers pooled the results from several studies and found that people who used Jenny Craig lost an average of at least 15 pounds and kept it off for at least 12 months, which was a 4.9% greater average weight loss than education or a control program. Members of Weight Watchers lost an average of at least 8 pounds and kept it off for at least 12 months, which was a 2.6% greater weight loss than education or a control program. Both commercial plans, which include behavioral counseling and social support, did better than the standard diet information or behavioral counseling to which the individual studies compared them.
Weight Watchers costs about $43 a month for membership and meetings, according to the Associated Press. Members do not need to buy Weight Watchers food products. Jenny Craig provides pre-made meals and can cost several hundred dollars per month, according to the Associated Press.
The review, which was published in the journal Annals of Internal Medicine, also looked at studies of plans from SlimFast, Atkins, Nutrisystem, Medifast, Optifast, and Health Management Resources. Although several of these plans showed promising weight-loss results, they had not been studied long enough, the researchers concluded. Several of the very-low-calorie programs such as Medifast and Optifast showed a 4% greater short-term weight loss, but weight loss slowed down after 6 months.
The authors of the review noted that many of the studies evaluated were shorter than a year in length and that many of the participants dropped out.