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Are Weight-Loss Programs Effective?

By Adam Gilden Tsai, MD, and Thomas A. Wadden, PhD
Reprinted from Eating Disorders Today
Summer 2005 Volume 3, Number 3
©2005 Gürze Books

Numerous commercial, self-help, and proprietary weight-loss programs have arisen in the last few decades. In an article published in the Annals of Internal Medicine, we studied the largest programs in the United States to determine what evidence, if any, exists to support their effectiveness.

We researched nationally available programs—Weight Watchers, Jenny Craig, LA Weight Loss, OPTIFAST, Health Management Resources (HMR), and eDiets—as well as self-help groups such as Overeaters Anonymous (OA) and Take Off Pounds Sensibly (TOPS).

The plans had to be organized, meaning that participants have regular visits, either in-person or online. Thus, we did not include the do-it-yourself diet plans such as Slim-Fast, Atkins, South Beach, or Zone.

Commercial Programs
The three largest non-medical programs in the country, Weight Watchers, Jenny Craig, and LA Weight Loss, train laypersons to provide counseling and are designed to help participants achieve a weight loss of 1 to 2 pounds per week, which is considered safe. Weight Watchers uses group counseling and costs $12 per week in most places. Jenny Craig and LA Weight Loss have individual counseling, and their prices vary. Jenny Craig is more expensive, mainly because the program requires that individuals buy its foods, which cost $70–$105 per week.

LA Weight Loss allows members to use their own foods, but the cost is difficult to estimate because the program requires a consultation to set a weight-loss goal. The program cost is the weekly charge (usually $7) multiplied by the number of weeks needed to reach the goal, not including start-up costs. Although Jenny Craig is significantly more expensive than Weight Watchers, the difference is narrowed once the usual cost of buying food is included.

Surprisingly, there has been little research to measure the success of these programs. One study randomly assigned 423 persons to attend either Weight Watchers group meetings or “usual care” (two 20-minute visits with a dietitian).

After two years, the Weight Watchers group maintained a 6.4 pound weight loss (compared to 0.5 pounds in a self-help group). Even though the Weight Watchers group lost weight, at $12 per week that cost would be $1,248 for 2 years of weekly meetings, equal to $208 per pound of weight lost.

There was one published study of Jenny Craig, but it didn’t account for all the persons who started the program, so the results are biased. Jenny Craig is currently sponsoring a study similar to the Weight Watchers trial, and the results should be available later this year. We did not find any research on the LA Weight Loss program.

Medical Programs
Medical weight-loss programs designed for obesity treatment are among the most expensive. These programs use very-low-calorie diets, usually meal replacement shakes or bars, and they aim for a weight loss of 3 pounds or more per week.

The two largest companies that offer these regimens are OPTIFAST and Health Management Resources (HMR). The combination of services provided in these plans (meal replacements, medical supervision including blood tests and electrocardiograms, and intensive counseling) makes them very expensive, approximately $3,000 for the initial two treatment phases, which include rapid weight loss and transition back to usual foods. Maintenance visits are not included in the prices.

While there are dozens of published studies on the OPTIFAST and HMR programs, most of the research lacks a comparison group, which makes it impossible to say whether they are more effective than any other approach. Even in the best studies of these programs, 25 to 50 percent of the individuals dropped out before finishing the first 6 months, which tells us that the diet is not easy to follow.

Among the individuals who finished, large amounts of weight were lost (between 45 and 55 pounds for a person starting at 220 pounds), but participants usually regained more than half of the lost weight during the maintenance phase (1 to 4 years after the program). The studies don’t tell us what happened to individuals that weren’t weighed 1 to 4 years after completing the program, but it is likely that they regained even more weight. An expert weight-loss panel (convened by the National Institutes of Health) concluded that very-low-calorie diets are no more effective than balanced low calorie diets for long-term weight loss.

Internet Programs
Internet dieting programs are new to the weight-loss industry, yet their success rates may be the lowest. There are many such programs, but we only found one that had been tested, eDiets.com. This website provides shopping lists, recipes, e-mail advice from weight-loss experts, and online chats with other members, for $5 per week.

In the single published research study, eDiets.com participants lost 2.3 pounds after 1 year, which was 5.5 pounds less than a comparison group of persons using a self-help book on weight loss.

Self-Help Organizations
Lastly, we studied organized self-help programs. These interventions are different from other programs in two ways. First, they are nonprofit, so they charge minimal or no fees for membership. Second, they rely on local volunteers to lead groups. Take Off Pounds Sensibly (TOPS) and Overeaters Anonymous (OA) are two such programs.

The TOPS plan is similar to Weight Watchers, in that it recommends the exchange diet. (The exchange diet is also recommended by the American Diabetic Association.) OA is unique among weight-loss plans, as it is a 12-step program that is modeled after the older Alcoholics Anonymous. The OA philosophy is that obesity results from compulsive eating, and compulsive eating results from depression and other negative emotions. Each participant is offered a sponsor whom they are encouraged to call daily with their progress. Thus, OA is intensive not only for new participants, but also for experienced persons who serve as sponsors.

TOPS and OA do not have the financial resources of the other programs, and so they are unlikely to perform a rigorous research study. Out of all the programs examined, however, these organizations might be the most beneficial for an eating disordered person seeking support.

The OA website states that participants who binge, purge, or practice self-starvation improve after going through the program. One study of OA showed a decreased frequency of binge eating among women with bulimia nervosa, but the study did not include a comparison group. Thus, OA might benefit eating disordered individuals or persons seeking emotional support, even without weight loss. However, OA should not be a substitute for counseling provided by a licensed mental health professional.

Adam Gilden Tsai, MD, and Thomas A. Wadden, PhD, both practice at the weight and Eating Disorders Program at the University of Pennsylvania.

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