Dieters looking to maximize their chances for long-term weight loss should consider trying Jenny Craig or Weight Watchers, according to a new review of clinical trials.
People who used the Jenny Craig program lost 4.9% more weight after one year than their counterparts, who only got dieting education or behavioral counseling, the review found. Jenny Craig clients work with a consultant to choose three prepared meals a day, plus a snack or dessert. In the clinical trials, clients lost weight regardless of whether they selected low-carb meals or items from the regular menu. They also succeeded whether they met with their consultant in person or over the phone.
In another set of clinical trials, people who used Weight Watchers dropped 2.6% more weight after one year than people in a control group who received only education. Weight Watchers, the most popular commercial program in the U.S. by far, allows dieters to eat whatever food they wish. However, it trains them to cut back on calories by using a “points” system that favors foods like watermelon and celery and leaves little room for indulgences. Dieters attend meetings or use an online program to keep track of their progress.
Although Jenny Craig users had the best outcomes, the program’s comparatively high cost may be prohibitive to some people, researchers wrote Monday in Annals of Internal Medicine. That’s why they also endorsed Weight Watchers as “the most cost-effective” option.
Of the roughly $2.5 billion that Americans spend on weight-loss services each year, about 45% goes to Weight Watchers, according to the market research firm IBISWorld. Another 13% is spent on Jenny Craig and 14% on Nutrisystem, which also involves premade, low-calorie meals.
The researchers could not find any solid clinical trials that tracked Nutrisystem customers for a full year. Over a three-month period, dieters on Nutrisystem lost 3.8% more weight than people who got education or counseling. Those results were promising, the researchers wrote, but not definitive enough to recommend alongside Jenny Craig and Weight Watchers, the study authors concluded.
Altogether, the researchers combed through more than 3,500 studies and considered 141 different weight-loss programs. But only 11 of the programs had been tested in rigorous clinical trials that lasted at least 12 weeks.
Three of the programs relied on diets that delivered a mere 800 to 1,000 calories per day. Among these, the Health Management Resources plan recorded the most weight loss – 13.2% more than counseling alone after six months – but it also had some worrisome side effects. More than half of the HMR dieters experienced constipation, and 6% needed to have their gallbladders removed to treat painful gallstones.
The other two programs produced short-term results that weren't sustained. Dieters using Medifast lost 5.6% more weight over four months than people who got counseling, but the difference between the two groups disappeared after nine months. Similarly, dieters on Optifast lost 4.2% to 9.2% more weight over four to five months than their counterparts who received counseling, but one trial that tracked people for one year found no difference at that point.
Another five weight-loss programs were described as “self-directed,” including three Internet-based plans. Among them, only the Biggest Loser Club was found to have any success – after three months, users lost 2.7% more weight than people in a control group. Another trial found that people who tried Lose It! lost about the same amount of weight over three months as people who got counseling. A third trial tracked users of eDiets for a year and found they fared no better than people who got counseling.
The results of four clinical trials involving SlimFast were mixed, the researchers found.
The researchers also found eight clinical trials involving Atkins. Seven of them compared the low-carb diet with behavioral counseling. In those studies, Atkins followers lost 0.1% to 2.9% more weight than their counterparts after one year. Another trial compared a group of Atkins dieters with a control group that got only education. After six months, the Atkins adherents lost 6.8% more weight than those in the control group.
“Although Atkins seems promising, we interpret these findings cautiously,” the study authors wrote. That’s because the experience of real-world dieters may differ from that of clinical trial participants, they said.
The results of this comprehensive review – the first since 2005 – are sure to be of interest to the roughly 30% of Americans who say they are on a diet. But the researchers who conducted the analysis hope their findings will also be useful to doctors.
The Patient Protection and Affordable Care Act advises physicians to screen for obesity and make sure patients in need get appropriate counseling and treatment. In addition, the American Heart Assn., the American College of Cardiology and The Obesity Society recommend similar interventions for patients who are either overweight or obese. The medical costs associated with obesity add up to about $150 billion a year, experts estimate.
Despite the need, most doctors aren’t equipped to provide weight-loss services themselves.
“Because the ACA is likely to increase obesity screening, having an actionable plan that addresses weight management is critical,” the study authors wrote. “It may be reasonable for clinicians to refer patients to Weight Watchers or Jenny Craig, especially if they lack the time, training, or ancillary staff to deliver behavioral counseling in their practices.”
With two-thirds of Americans either overweight or obese, more states – and more doctors – should consider joining them, according to an editorial that accompanies the study.
“Programs that help patients restrict calories with a structured approach to making healthier, real-world dietary choices, such as Weight Watchers, may fare better over the long term than programs that rely solely on prepackaged meals or supplements,” wrote Dr. Christina Wee, director of the Health Services and Behavioral Research Program in Obesity at Beth Israel Deaconess Medical Center in Boston. However, this assumption “would need to be confirmed in future studies,” she added.