Adam Gilden Tsai, MD; Thomas A. Wadden, PhD
Acknowledgments: The authors thank Kirstin Byrne, MS, for research and editorial assistance.
Grant Support: In part by grants 2-T32-HP-010026 and K24-DK-065018 from the National Institutes of Health.
Potential Financial Conflicts of Interest:Consultancies and grants received: T.A. Wadden (Novartis Nutrition, manufacturer of OPTIFAST).
Requests for Single Reprints: Thomas A. Wadden, PhD, Weight and Eating Disorders Program, University of Pennsylvania, 3535 Market Street, Suite 3029, Philadelphia, PA 19104; e-mail, email@example.com.
Current Author Addresses: Drs. Tsai and Wadden: Weight and Eating Disorders Program, University of Pennsylvania, 3535 Market Street, Suite 3029, Philadelphia, PA 19104.
Tsai A., Wadden T.; Systematic Review: An Evaluation of Major Commercial Weight Loss Programs in the United States. Ann Intern Med. 2005;142:56-66. doi: 10.7326/0003-4819-142-1-200501040-00012
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Published: Ann Intern Med. 2005;142(1):56-66.
Each year millions of Americans enroll in commercial and self-help weight loss programs. Health care providers and their obese patients know little about these programs because of the absence of systematic reviews.
To describe the components, costs, and efficacy of the major commercial and organized self-help weight loss programs in the United States that provide structured in-person or online counseling.
Review of company Web sites, telephone discussion with company representatives, and search of the MEDLINE database.
Randomized trials at least 12 weeks in duration that enrolled only adults and assessed interventions as they are usually provided to the public, or case series that met these criteria, stated the number of enrollees, and included a follow-up evaluation that lasted 1 year or longer.
Data were extracted on study design, attrition, weight loss, duration of follow-up, and maintenance of weight loss.
We found studies of eDiets.com, Health Management Resources, Take Off Pounds Sensibly, OPTIFAST, and Weight Watchers. Of 3 randomized, controlled trials of Weight Watchers, the largest reported a loss of 3.2% of initial weight at 2 years. One randomized trial and several case series of medically supervised very-low-calorie diet programs found that patients who completed treatment lost approximately 15% to 25% of initial weight. These programs were associated with high costs, high attrition rates, and a high probability of regaining 50% or more of lost weight in 1 to 2 years. Commercial interventions available over the Internet and organized self-help programs produced minimal weight loss.
Because many studies did not control for high attrition rates, the reported results are probably a best-case scenario.
With the exception of 1 trial of Weight Watchers, the evidence to support the use of the major commercial and self-help weight loss programs is suboptimal. Controlled trials are needed to assess the efficacy and cost-effectiveness of these interventions.
Director of Research, Health Management Resources
January 5, 2005
HMR Data Refutes Findings of Research Article
While we applaud Drs. Tsai and Wadden's call for more outcome data from weight loss programs, we were mystified by their conclusion.
Due to the narrow criteria imposed by the authors, several recent studies from Health Management Resources (HMR) were not included. While randomized, controlled trials are one type of study, other available data should not be ignored. Ongoing data from treatment programs should be considered valid since a natural "control" group exists in overweight, non -dieting Americans (people, on average, are gaining at least 1 lb yearly)1. Furthermore, the authors call for "naturalistic studies" that follow a large cohort to determine the percentage of persons who complete various phases of treatment and the amount of weight lost. When offered such data from HMR from dozens of major medical centers, the authors refused to consider it.
It is difficult to see how the authors reached the conclusion that Weight Watchers was the most successful program especially since they acknowledge that HMR's weight losses are greater than 20% of initial weight (50-60 lbs). By their own analysis, participants in Weight Watchers were keeping off 3.2% of initial body weight at two years while HMR participants were keeping off 15.2% (6.4 vs. 30.4 lbs for a 200 lb person). For people needing to lose weight and decrease their medical risk factors (e.g., diabetes, heart disease, hypertension) a loss of 6 lbs. is barely sufficient. Research clearly shows that greater weight loss leads to greater changes in medical risk factors2.
A grave error exists in the cost analysis. Since the HMR Program includes the cost of meal replacements, the only fair comparison with other programs is to include the ongoing, normal cost of food. Once that cost is added (approximately $58 for in-home3 and $48 for outside eating per week4), the "real cost" for Weight Watchers rises to approximately $100 per week "“ more than food costs in any HMR treatment option, with less weight loss. In fact, one study found that food costs were actually lower with programs providing meal replacements5.
HMR has pioneered a research-based weight management program for over 20 years. Our data indicate that HMR patients are eating over 35 servings of fruits and vegetables and doing over 2,000 kilocalories of exercise per week, while using meal replacements to lower caloric intake. It is a shame the authors have given the impression that this is not successful, cost- effective, healthy weight loss.
1. Rothacker DQ, Blackburn GL. Obesity prevalence by age group and 5- year changes in adults residing in rural Wisconsin. J Am Diet Assoc 2000;100:784-790.
2. Anderson JW, Brinkman-Kaplan VL, Lee H, Wood CL. Relationship of weight loss to cardiovascular risk factors in morbidly obese individuals. J Am Coll Nutr 1994;14:256-261.
3. United States Department of Agriculture. Official USDA Food Plans: Cost of Food at Home at Four Levels, U.S. Average, November 2004 (Accessed January 4, 2005, at http://www.cnpp.usda.gov/FoodPlans/Updates/foodnov04.pdf)
4. U.S. Department of Labor. Consumer Expenditures in 2002 (Accessed January 4, 2005, at http://www.bls.gov/cex/csxann02.pdf)
5. Hart K, Greenwood H, Truby H. Pound for pound? Comparing the costs incurred by subjects following four commercially available weight loss programmes. J Hum Nutr Diet 2003;16:365.
Employee of Health Management Resources
George L. Blackburn
Beth Israel Deaconess Medical Center, Harvard Medical School
January 21, 2005
selecting Commercial Weight Loss Programs
Tsai and Wadden's recent review of major commercial weight loss program outcomes underscores the importance of identifying "Best Practices" in such programs. Their conclusions are derived from state-of- the-art evidence-based methodology. Today's gold standard in evidence- based medicine is the well-conducted and well-executed randomized controlled trial (RCT), an approach known to minimize potential biases. However, there are few RCTs in the field of nutrition medicine. In many cases, the next best evidence is prospective observational studies or population-based registries. Data show that well-conducted observational studies do not appear to produce results that are biased compared with randomized trials (1).
Another example of "Best Practices" is the recent Lehman Center Executive Report on Weight Loss Surgery (2). All selected studies were critically assessed for internal validity, and ranked according to levels of evidence based on a similar grade system. For example, Category D evidence--including clinical experience, opinions of respected authorities, reports from expert panels--was used in conjunction with evidence from RCTs or observational studies.
Tsai and Wadden deem the evidence to support weight loss programs "suboptimal," due to high attrition rates and the lack of RCTs. But what are the positives? The 15-25% weight loss under the medically supervised VLCD programs should be considered a success for patients who completed treatment. Modest weight loss provides beneficial health effects and is both achievable and valued by overweight and obese patients (3). Based on the recent Dansinger et al. study (4) comparing four popular diet plans, it appears that the methods used to adhere to the diet plan, and not the plan itself, are most critical for successful weight loss. Success is certainly achievable: statistics indicate almost 50% of American adults who have tried to lose weight have maintained a 10% loss from their baseline weight for at least one year (5). The commercial programs reviewed by Tsai and Wadden have the potential to achieve long-term adherence, particularly in combination with physician monitoring and support.
1. Concato J, Shah N, Horwitz RI. Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med. 2000;342:1887-1892.
2. Blackburn GL, Hu FB, Harvey A. Evidence-based recommendations for best practices in weight loss surgery. Obes Res. 2005:(in press).
3. Wee CC, Hamel MB, Davis RB, Phillips RS. Assessing the value of weight loss among primary care patients. J Gen Intern Med. 2004;19:1206- 1211.
4. Dansinger ML, Gleason JA, Griffith JL, Selker HP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA. 2005;293:43-53.
5. McGuire MT, Wing RR, Hill JO. The prevalence of weight loss maintenance among American adults. Int J Obes Relat Metab Disord. 1999;23:1314-1319.
Thomas A. Wadden
University of Pennsylvania
March 8, 2005
Drs. Tsai and Wadden respond
To the Editor,
We appreciate the points raised by Dr. Gotthelf from Health Management Resources (HMR).
Dr. Gotthelf cites our call for naturalistic studies to determine the effectiveness of weight loss programs and states that she offered such data, which we declined. We outlined very specific criteria for original research to be included in our review, one of which was that the data had to be published in a journal. We applaud HMR for collecting further data from observational studies and encourage the company to submit these findings for peer review.
Dr. Gotthelf states that we concluded that Weight Watchers was the most successful program. We did not state this, but rather, concluded that Weight Watchers was the most rigorously tested program. We agree that a 15% loss of initial weight, as found in one HMR study, is more clinically significant than a 3% loss. However, most persons treated in medically- supervised programs do not maintain a loss of 15% of initial weight at 2 to 3 years. In one of HMR's naturalistic studies, patients lost 19.2% of initial weight in 20 weeks but maintained a loss of only 7.3% at 3.4 years. This follow-up evaluation did not include 42% of the original sample, and the findings were not adjusted (using a baseline-carried- forward analysis) to account for the dropouts (1). Randomized comparisons of very-low-calorie diet regimens (as used in the HMR studies) and low- calorie diets (providing 1200-1500 kcal/day) have shown no difference in long-term weight losses (2), principally because of greater weight regain with the former approach.
Finally, Dr. Gotthelf states that we incorrectly estimated costs by including the price of meal replacements for medically-supervised programs but not for programs that do not require meals to be purchased. This is a valid point. Our goal was to estimate the actual out-of-pocket costs associated with participating in each program. Clearly, participants must continue to purchase food when dieting. Some may spend approximately $80 per week on food, comparable with the costs of HMR's meal plan. Others, however, may spend substantially less. In reviewing Dr. Gotthelf's cited sources, we believe she has overestimated the usual costs of food.
In general, the programs we reviewed, including HMR, are among the better options available to patients who wish to lose weight. Many are members of the Partnership for Healthy Weight Management and provide appropriate information to potential clients (3). Our intention was not to disparage the important service provided by these programs, but rather, to review the available evidence and to encourage publication of further research.
Adam Gilden Tsai, MD
Thomas A. Wadden, PhD
Weight and Eating Disorders Program, University of Pennsylvania
1. Anderson J, Hamilton C, Crown-Weber E, Riddlemoser M, Gustafson N. Safety and effectiveness of a multidisciplinary very-low-calorie-diet program for selected obese individuals. J Am Diet Assoc. 1991;91(12):1582- 1584. 2. National Heart Lung and Blood Institute (NHLBI). Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults--The Evidence Report. National Institutes of Health. Obes Res. 1998;6 Suppl 2:51S-209S. 3. Partnership for Healthy Weight Management. Voluntary guidelines for providers of weight loss products or services. www.consumer.gov/weightloss; accessed October 2003.
Potential Financial Conflicts of Interest: Consultancies and grants received: T.A. Wadden (Novartis Nutrition, manufacturer of OPTIFAST).
March 15, 2005
Response to Drs. Blackburn and Waltman
To the editor,
We welcome the points raised by Drs. Blackburn and Waltman concerning our review of commercial and organized self-help programs for weight control.
Blackburn and Waltman remind us that well-conducted observational studies can yield useful results, particularly in the area of nutrition medicine/weight loss. We agree. Indeed, most of the studies of medically- supervised programs that we reviewed were observational studies. However, the randomized trial of Weight Watchers demonstrates that it is possible to carry out a "gold-standard" study. Although it is unlikely that the organized self-help programs will have the resources to conduct such studies, we encourage other commercial programs to compare their interventions to usual care. In the case medically-supervised programs that are fee-for-service, we believe that patients would accept randomization to diets that had different energy levels (e.g., 700 vs. 1200 kcal/d) or compared a liquid diet with one that combined a liquid supplement and an evening meal of food. Anderson et al have shown that such studies are acceptable to patients (1).
Blackburn and Waltman cite evidence that weight loss maintenance is common in the general population and suggest that commercial programs may be useful to achieve long-term weight management. We agree that such programs are potentially helpful and that physician monitoring and support is crucial. We concur with Blackburn and Waltman regarding the benefit of modest weight loss, and we would add that cost-effectiveness should be considered in selecting a weight loss program.
1. Anderson JW, Brinkman-Kaplan V, Hamilton CC, Logan JE, Collins RW, Gustafson NJ. Food-containing hypocaloric diets are as effective as liquid -supplement diets for obese individuals with NIDDM. Diabetes Care. 1994;17(6):602-4.
Potential Financial Conflicts of Interest: Consultancies and grants received: T.A. Wadden (Novartis Nutrition, manufacturer of OPTIFAST).
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