The world of commercial diet programs can be overwhelming, with this, that and the other company all flashing before-and-after photos and promising their regimens are the best. While we’ve all seen the “results not typical” disclaimer flash on the screen below weight-loss winners, how effective are these programs when it comes to really losing the weight and keeping it off?

Researchers publishing a study in the Annals of Internal Medicine looked into the efficacy of commercial diet programs, but found that beyond the popular Weight Watchers and Jenny Craig systems, there really wasn’t much evaluation of other programs’ long-term results available.

The study’s authors compared weight loss, how long people retained that weight loss and potential harms of weight-loss programs against a control of just being educated and receiving only printed materials or fewer than three sessions with a provider or behavioral counseling, among overweight and obese adults.

There were a total of 11 popular diet programs included in the results of 45 studies the researchers looked at, with Weight Watchers and Jenny Craig coming out on top of things like the Atkins Diet and Medifast. None of the diet companies were involved in carrying out the study.

After 12 months Weight Watchers participants had 2.6% greater weight loss than the control groups, while people on Jenny Craig’s system had at least 4.9% greater weight loss.

To put it another way, the researchers found that Weight Watchers dieters shed on average at least 8 pounds and kept it off for at least 12 months, while Jenny Craig participants lost at least 15 pounds and kept it off for a year as well.

“It’s a really important first step to reach,” even if it doesn’t meet patients’ expectations, study author Dr. Kimberly Gudzune, an internist and researcher at Johns Hopkins University’s medical school told the Associated Press.

Efficacy of Commercial Weight-Loss Programs: An Updated Systematic Review [Annals of Internal Medicine]
Weight Watchers, Jenny Craig get best marks in diet review [Associated Press]

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.