A comparison of popular commercial weight loss programs finds that many do not have a great deal of evidence supporting them.
A systematic review in the Annals of Internal Medicine analyzed 45 studies comparing weight loss programs to behavioral counseling groups or control groups that received dietary education. The programs reviewed included Weight Watchers, Jenny Craig, Nutrisystem, Atkins, The Biggest Loser, Medifast and SlimFast.
Many of the trials lasted no more than a few months. However, studies of Weight Watchers and Jenny Craig showed 2.6% and 4.9% greater weight loss respectively than the comparison groups after one year of dieting.
Drop-Out Rates
One challenge of weight loss programs is getting people to stay with the plan. Low-calorie programs had especially high drop-out rates.
Gallstones are a risk of weight loss, and some people in each of these programs developed them. Many overweight people might expect to lose substantially more pounds than the study subjects did, based on the advertising. They could well be disappointed with their actual results.
