Dieters disillusioned when their results vary from those of the attractive participants who tout weight-loss products and claim dramatic success may find more reliable information in a recently published University of Pennsylvania Health System evaluation of weight-loss programs in the United States.
Of all the programs out there,
Thomas Wadden and Adam Tsai of UPHS hope to change the trend of misleading advertising through their study -- recently published in the Annals of Internal Medicine -- examining the qualifications of staff, costs, efficacy and risks of major weight-loss programs.
"The goal is to provide consumers with the most information," said Wadden, who is the director of the Weight and Eating Disorders Program at Penn.
If the weight-loss program does not provide reliable evidence that suits the participants' needs, the participants should leave the program, Wadden said.
In evaluating the efficacy of commercial weight-loss programs, Wadden and Tsai included randomized studies published from 1966 to 2003. All of the studies treated adults and lasted more than 12 weeks, with weight assessment a year after program completion.
However, Wadden and Tsai discovered a scarcity of studies meeting their criteria.
Of the three major non-medical commercial weight-loss programs reviewed, only Weight Watchers had sponsored controlled trials of its program.
"We found no such evaluations of Jenny Craig or L.A. Weight Loss," Wadden and Tsai wrote in their report.
Studies showed that Weight Watchers patients lost about 5 percent of their starting weight over three to six months and kept off 3 percent after a year.
"It's a very modest weight loss, but modest weight loss can lead to health benefits," said Wadden.
Jennifer Mitchell, public relations manager of the eastern region of Weight Watchers, agrees that dieters should focus on the significant health benefits associated with weight loss.
Mitchell argues, however, that 5 percent weight loss in three to six months should not be described as "modest."
"It's actually the recommended weight loss rate and should not be considered a small feat. ... We need to adjust our expectations with weight loss and focus on what really matters," said Mitchell, adding that such weight loss can reduce the probability of the development of diabetes.
Wadden and Tsai encourage commercial programs to conduct controlled trials that result in reliable weight-loss statistics.
"The consumer and healthcare professionals are looking for science-based evidence and hard facts," said Lisa Talamini, chief nutritionist and director of program development at Jenny Craig.
And according to Talamini, Jenny Craig is set to complete its first scientific study, begun in November, in the hope of supporting its own research.
Wadden and Tsai's review also included medically supervised proprietary programs, such as OPTIFAST, Health Management Resources and Medifast. These diets typically employ very low calorie intakes -- less than 800 per day.
However, diets that provide less than 800 calories per day also could result in heart-rhythm abnormalities, which can be fatal, according to the Weight-control Information Network of the National Institutes of Health.
