What You Can Change _. And What You Can't - Martin E. Seligman [92]
The “Oprah effect” was no surprise to the scientific community. Even before Oprah went on her VLCD, a definitive study of her diet had been published. Five hundred patients on Optifast began at an average of 50 percent over their “ideal” weight. More than half of these patients dropped out before treatment was complete. The rest, like Oprah, lost a great deal of weight—an average of 84 percent of their excess weight. An excellent result. Over the next thirty months, the patients, like Oprah, regained an average of about 80 percent. In another follow-up of VLCD, only 3 percent of the patients were considered successes after five years. In yet another study of VLCDs, 121 patients were followed for years after they lost 60 pounds on average. Half were back at their old weight after three years, 90 percent after nine years. Only 5 percent remained at their reduced weight. The best result I can find is a study in which 13 percent of subjects remained thin after three years.8
No other diet has been shown to work in the long run. There are about a dozen well-executed long-term studies involving thousands of dieters, and all of them show basically the same dismal result: Most people gain almost all their weight back in four to five years, with perhaps 10 percent remaining thin. The longer the follow-up, the worse the outcome. The trajectory points to complete failure after enough time elapses.9 More telling than what is published is what is not published. There has been dead silence from the commercial programs. They have long-term weight figures on tens of thousands of their clients, but they have kept their findings secret. It doesn’t take a Sherlock Holmes to figure out why.
A few diet experts take the view that enough is enough: Dieting is a cruel hoax, and it is time for Congress to intervene. Many sit glumly on the fence, perhaps awaiting the day of reckoning. But some respected experts call for new and more innovative diets with far more attention paid to maintenance. Drs. Kelly Brownell and Tom Wadden, two leading obesity researchers, have called for a national obesity campaign with the goal of a ten-pound loss by all overweight Americans.10 These optimists have one plausible argument: Almost all the long-term failures are patients—obese people who go to hospital clinics. These may be the most hopeless cases, the terminally fat. Maybe diets will work better on the slightly overweight, the people who don’t need to go to clinics, the people who have not repeatedly tried and failed.
I doubt it. Workplace and home-correspondence interventions have fared just as poorly as hospital clinics.11 Maybe someone will discover a way to screen overweight people so that only the ones likely to succeed will be accepted for dieting programs. Maybe someone will have that new insight into maintenance that has thus far eluded everyone. But in the meantime, the clearest fact about dieting is that after years of research, after tens of millions of dieters, after tens of billions of dollars, no one has found a diet that keeps the weight off in any but a small fraction of dieters.12
Yo-yo Dieting
Rats permanently change the way they deal with food after they have been starved once. After they regain the weight, their metabolism slows. They like fatty foods more. They accumulate larger fat deposits. The more cycles of famine and feast, the better they get at storing energy. They may even rebound from starvation to a higher weight than ever before once food is abundant again.13
It looks as if people do the same thing. After dieting, people radically change the way they deal with food. Dieters become intensely preoccupied with food, thinking about it all day long, even dreaming about it. The body changes, hoarding