Losing weight isn't easy, so some of us rely on scientific studies and reports to know how best to go about tackling the long road to health and happiness. The public thirst for insights into weight loss seems unquenchable though academic science does its best to keep up. New information suggests that very little of that advice is actually reliable.
A review by John Hopkins University of thousands of studies of weight-loss programs suggests that few can be proven to have long-term benefits. The evidence-gathering of most of the studies was unreliable with researchers finding only a few dozen of the studies that were scientifically rigorous and reliable enough to be used in making effective decisions about our health.
The team at John Hopkins examined the results of 4,200 previous studies that had looked at how effective methods of weight loss were. The aim of the researchers was to help doctors guide obese and overweight patients who were considering a commercial weight-loss program. According to the results, "only a few dozen of the studies met the scientific gold standard of reliability." The results of the review were published recently in the Annals of Internal Medicine. They suggest that only a few weight-loss programs can demonstrate that those who were involved in them were more likely to have succeeded in losing weight than those who were not.
Part of this "gold standard" includes being a randomized clinical trial where participants are randomly assigned to either an experimental group or a control group — preferably neither the subjects nor those collecting the data know who is receiving the treatment and who isn't. This is known as the "double blind" method and it minimizes the potential for human bias in clinical studies. The researchers looked at peer-reviewed research articles from two major databases as well as the weight-loss programs themselves. So they would select the best examples of research, the investigators focused only on those studies that lasted 12 weeks or more.
Looking at 32 major commercial weight-loss programs marketed nationwide, the authors found that only 11 have been rigorously studied in randomized controlled trials — and only two of those came up to the required standard of testing that meant they were proven to be better at helping with weight loss than self-directed dieting or "other forms of other forms of education and counseling sessions." Even in programs proven to be effective, the authors describe the results as “modest,” with participants losing, on average, between 3 and 5 percent more than those in control groups.
Those programs that fared best were Weight Watchers and Jenny Craig — studies into these used data from a period of 12 months or more and produced results that showed weight loss in participants was demonstrably greater than non-participants. Given this, and until more reliable studies can be done, the authors conclude “it may be reasonable for clinicians to refer patients to Weight Watchers or Jenny Craig.” Nutrisystem also showed promising results for a three-month period but no accurate long-term trials were available. Studies of the Atkins diet suggest that it helps people "lose more weight at six months and 12 months than counseling alone," while "no definite conclusions could be made about Slim-Fast and the Internet-based programs."
According to John Hopkins, excess weight and obesity is a problem that affects two thirds of U.S. adults. With weight-loss programs representing a $2.5 billion-per-year business in 2014, the competition to publish the best results heats up. With the Affordable Care Act making obesity screening potentially available to a growing number of people, the authors predict that doctors will be advising more patients to take advantage of weight-loss programs in the near future. “Primary care doctors need to know what programs have rigorous trials showing that they work, but they haven’t had much evidence to rely on,” says Dr. Kimberly Gudzune, an assistant professor of medicine and a weight-loss specialist at the Johns Hopkins University School of Medicine. “Our review should give clinicians a better idea of what programs they might consider for their patients.”
The results of this review are not conclusive, the researchers at John Hopkins say. They make it clear that not all the studies they looked at were equally well designed meaning direct comparison is not easy. The authors also note that, since most trials ran less than the required 12-month period, it was not always possible to accurately record how many people had lost weight in a sustained way. They point out the need for more thorough tests over longer periods so a clearer picture can be established. Co-author of the study, Dr. Jeanne Clark says that losing weight is most important for its long-term dividends: avoiding high blood pressure and cholesterol and lowering the risk of diseases like diabetes by controlling blood sugar. “Losing weight for three months, then regaining it has limited health benefits," she says, that’s why it’s important to have studies that look at weight loss at 12 months and beyond."
Undoubtedly, weight loss is a personal battle and different folks may well need different strokes. However, considering the vast quantity of information out there — coming from both academic and commercial sources — reviews like these can mean a greater sense of clarity for you, the end consumer. Knowing which programs are most likely to yield best results is important for you, your doctor and your pocket. And that has to mean a weight off the mind for everyone.