Key messages from scientific research that's ready to be acted on
Got It, Hide thisGudzune KA, Doshi RS, Mehta AK, et al. Efficacy of commercial weight-loss programs: an updated systematic review. Ann Intern Med. 2015;162:501-12.
In overweight or obese adults, do commercial weight-loss programs increase weight loss?
Excess body weight can have negative effects on health and increases the risk of heart disease, diabetes, and osteoarthritis. Modest weight loss can improve or prevent these negative health effects. Some common commercial weight loss programs include Weight Watchers, Jenny Craig, and Atkins.
The researchers did a systematic review, searching for articles published up to November 2014. They found 39 randomized controlled trials with 5447 people (average age range 37 to 57 years).
The trials included overweight or obese adults.
Commercial weight-loss programs were compared with education (printed materials only, health education curriculum, or fewer than 3 sessions with a care provider) or no intervention, or behavioural counselling (at least 3 sessions with a care provider) for at least 12 weeks.
The quality of the studies was generally moderate to low. In several trials, many people did not return for final measurements. The weight measurements missing from these people could make the results of these studies less certain.
Few studies measured weight loss after 1 year; most measured weight loss at 3 to 12 months.
Some of the weight-loss programs resulted in greater weight loss than education or no intervention, or than behavioural counselling (see Table below).
In overweight or obese adults, some commercial weight-loss programs improve weight loss compared with education or no intervention or compared with behavioural counselling.
Comparisons | At 3 months to less than 1 year | At 1 year or later |
Weight Watchers vs education or no intervention | People lost 2.5% to 7.9% more weight with Weight Watchers (7 trials)* | People lost 2.6% to 3.2% more weight with Weight Watchers (4 trials) |
Weight Watchers vs behavioural counselling | In 2 trials, people lost 0.8% to 3.2% more weight with Weight Watchers, but in another trial they gained 1.1% more weight | In 1 trial, people lost 2.9% more weight with Weight Watchers, but in another trial, they gained 0.7% more weight |
Jenny Craig vs education or no intervention | People lost 7.5% more weight with Jenny Craig (1 trial) | People lost 6.4% more weight with Jenny Craig (1 trials) |
Jenny Craig vs behavioural counselling | People lost 5.7% to 8.1% more weight with Jenny Craig (4 trials) | People lost 4.7% to 8.3% more weight with Jenny Craig (6 trials) |
Nutrisystem vs education or no intervention | People lost 6.7% more weight with Nutrisystem (1 trial) | Not assessed |
Nutrisystem vs behavioural counselling | People lost 3.8% to 5.7% more weight with Nutrisystem (3 trials) | Not assessed |
Health Management Resources vs education or no intervention | People lost 8.1% to 22% more weight with Health Management Resources (3 trials) | Not assessed |
Health Management Resources vs behavioural counselling | People lost 12% to 13% more weight with Health Management Resources (2 trials) | Not assessed |
Medifast vs behavioural counselling | People lost 1.9% to 5.6% more weight with Medifast (2 trials) | Not assessed |
Optifast vs behavioural counselling | People lost 1.0% to 9.2% more weight with Optifast (9 trials) | People lost 2.3% more weight with Optifast (1 trial) |
Atkins vs education or no intervention | People lost 6.8% more weight with Atkins (1 trial) | Not assessed |
Atkins vs behavioural counselling | People lost 0.7%to 6.2% more weight with Atkins (11 trials) | In 6 trials, people lost 0.1% to 2.9% more weight with Atkins, but in 1 trial, people gained 1.0% more weight with Atkins |
Slimfast vs education or no intervention | In 4 trials, people lost 0.1% to 8.7% more weight with Slimfast, but in 1 trial, people gained 0.6% more weight | People lost 5.2% to 5.6% more weight with Slimfast (3 trials) |
Slimfast vs behavioural counselling | In 3 trials, people lost 0.4% to 3.2% more weight with Slimfast, but in 1 trial, people gained 0.3% more weight; in 1 trial, people neither gained nor lost more weight with Slimfast | In 1 trial, people lost 2.3% more weight with Slimfast, but in another trial, they gained 1.8% more weight |
Biggest Loser vs education or no intervention | People lost 2.7% more weight with Biggest Loser (1 trial) | Not assessed |
eDiets vs behavioural counselling | People gained 2.3% more weight with eDiets (1 trial) | People gained 1.8% more weight with eDiets (1 trial) |
Lose It! vs behavioural counselling | People gained 0.7% more weight with Lose It! (1 trial) | Not assessed |