Weight Loss Programs: Less Is More

Considering the number of overweight and obese people in the US - about two-thirds of the population - it might seem obvious that most weight loss programs aren't successful. Still, it's surprising to find out that little or no evidence has been published proving that the most popular commercial weight loss programs work at all.

A recent review in the Annals of Internal Medicine (2005;142, 1:56-66) evaluated major commercial weight loss programs and found that most supplied no scientifically valid, published evidence that they helped people lose weight or keep it off. The data that is available shows only modest amounts of weight lost, with even less kept off over time.

In Systematic Review: An Evaluation of Major Commercial Weight Loss Programs in the United States, authors Adam Gilden Tsai, MD, and Thomas A. Wadden, PhD, assessed more than 1500 abstracts or titles looking for those that met their criteria for review. For instance, they only included studies that were conducted on adults in the US, had 10 or more participants and lasted 12 weeks or more. The studies had to have been done under conditions that were the same as they would be for any member of the public - not, say, in a lab - and to have a follow-up evaluation period of at least one year.

Few Studies Meet Criteria
The authors found only 10 studies that met their criteria (three from Weight Watchers, three from Health Management Resources, two from OPTIFAST and one each from eDiets.com and TOPS). The results were sobering. In one of the Weight Watchers studies, participants lost about 7.5% of their total body weight over a 3-month period. For a 200-lb person, that would be 15 lbs. The one Weight Watchers study that checked in with participants longer-term noted an average sustained loss of 5.3% after 1 year and 3.2% after 2 years, or, for that same 200-lb person, 10.6 lbs and 6.4 lbs, respectively. And that's the good news.

Studies from medically supervised programs offered by Health Management Resources and OPTIFAST seemed to promise better results. These are stringent, low-calorie plans that produced weight losses of about 15% to 25% of body weight during the initial treatment period; those who were followed for a year maintained an average 8% to 9% weight loss. Participants who were tracked further maintained about a 7% loss after 3 years and 5% after 4 years. But these studies only counted the people who finished the program, not those who dropped out - as many as 56% of the participants. And medically supervised programs are expensive, requiring up to $2100 for the first three months.

Internet-based and self-help programs fared even worse in the review, and the authors state that there's minimal evidence that would support their use.

It's worth noting that even minor weight loss can be significant in terms of improving symptoms of disorders, such as diabetes, that are associated with overweight and obesity. And some programs will help some people lose some weight. The authors aren't saying that no commercial weight loss programs work, they're just saying there is no published scientific evidence that they do.

So where does one look for reasonable advice about what really works?

Principles Stress Sensible Guidelines
Most of us already know what it takes to lose weight and keep it off. For sound advice, look no farther than The Partnership for Healthy Weight Management, a coalition made up of representatives from science, academia, the health care professions, government, commercial enterprises, and organizations promoting the public interest. The mission of the Partnership is "To promote sound guidance to the general public on strategies for achieving and maintaining a healthy weight (defined as a body mass index of >19 and <25 among all people aged 20 or over)."

The principles of The Partnership for Healthy Weight Management are as follows, stated on the website of the Federal Trade Commission, which oversees the advertising claims of commercial weight loss programs.

• Following sensible and healthy guidelines for eating and physical activity is important for healthy weight management.
• Obesity is a serious, chronic disease that is known to reduce life span, increase disability and lead to many serious illnesses including diabetes, heart disease, and stroke. "Obesity" is defined as a body mass index (BMI) equal to or greater than 30, which approximates 30 pounds of excess weight. Excess weight also places people at risk of developing serious health problems.
• Excess weight is caused by an interaction of genetic (inherited) and environmental (social and cultural) factors, which include metabolic (physical and chemical) and behavioral (psychological and emotional) components. Because of the complexity of weight loss, gain, and maintenance, promises of quick and effortless weight loss are worthless.
• A sedentary lifestyle is a significant barrier to successfully maintaining weight loss and preventing further weight gain.
• Losing weight requires burning more calories than the body takes in, by either reducing caloric intake or increasing caloric expenditure, or preferably, both.
• Achieving and maintaining even a modest amount of weight loss can reduce the severity of illnesses associated with obesity.
• Effective weight management involves behavior modification which is a lifelong commitment and includes at least two components: 1) healthful eating in accordance with the Dietary Guidelines for Americans, emphasizing a reduction in total calories, a lowered fat consumption, and an increase in vegetables, fruits and whole grains, and 2) increased frequent and regular physical activity of at least moderate intensity.
• Medical, pharmacological and surgical interventions may be options for individuals with more serious cases of overweight and obesity. These interventions, used in conjunction with a plan for healthy eating and physical activity, should be utilized in conformance with applicable treatment guidelines.
• The consumer is entitled to accurate, reliable, and non-deceptive information about methods for weight management. The Partnership encourages weight loss providers to adopt the Partnership's Voluntary Disclosure Guidelines for Providers of Weight Loss Products and Programs.
• The Partnership opposes discrimination, including discrimination based upon size or weight.
• The Partnership does not endorse any particular product or program for weight loss or weight management.

Despite our yearning for a quick fix, the only proven "program" is the one we've heard about all our lives: eat less, eat well, and exercise more.

Eileen Early, BA, BSN, RN
HealthLink Editor

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.