Review of Commercial Weight-Loss ProgramsWednesday, February 18, 2009
So after yesterday’s CMAJ editorial, in which Yoni and I blasted some practices of commercial weight loss programs, created a flurry of media interest (including on the front page of the Globe & Mail as well as national TV), here is the best available sytematic review of commercial weight-loss programs in the US, published in the Annals of Internal Medicine by Tsai and Wadden from the University of Pennsylvania School of Medicine in 2005.
The authors reviewed company Web sites, conducted telephone discussion with company representatives, and searched the MEDLINE database.
All randomized trials of 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 were examined.
Of 3 randomized, controlled trials of Weight Watchers, the largest reported a loss of 3.2% of initial weight at 2 years – this is very much in the same ball park as the long-term results of some of the best academically run behavioral programs. One randomized trial and several case series of medically supervised very-low-calorie diet programs (like OPTIFAST) found that patients who completed treatment lost approximately 15% to 25% of initial weight.
All 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.
The authors note that because many studies did not control for high attrition rates, the reported results are probably a best-case scenario. Thus, 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.
Nevertheless, programs like Weight Watchers (a member of the Edmonton WeightWise (WW) Community Network) or OPTIFAST (often used in WW as a rescue strategy in Stage 4 patients and also provided by a WW Community Network Partner) may be effective in some individuals and can be part of a long-term weight management strategy for selected patients.
However, clearly most commercial weight-loss programs (and products) have yet to be studied in large controlled trials.
So how are commercial programs different from ethical, evidence-based programs, such as Alberta Health Services’, Edmonton-based WW program? While we may still have high attrition rates and results that are in line with reported outcomes for behavioural, pharmacological and surgical trials (i.e. weight loss in the range of 5 to 35%) – at least we do not claim, advertise or sell services that are not based on best evidence.
In fact, a notable feature of the WW program is an orientation session that every patient has to attend before being seen in the clinic, which certainly leaves no doubt as to the challenges and limited magnitude of long-term weight loss that can be expected – for some patients just stopping the gain is success!
Furthermore, as befits an academic-based program, WW patients on the waiting list as well as those receiving medical and/or surgical treatment arms are being prospectively followed in a 3-year study funded by the Canadian Institutes of Health Research (APPLES).
We recognize that access to and options for obesity treatment are limited within the public health care system. However, this should not serve as an excuse to scam individuals challenged by excess weight out of their money by promising results that are inconsistent with the best evidence. WW does not recognize as Community Partners weight-loss programs, whose results are solely based on anecdotes or testimonials (always a Red Flag to watch out for).