You’ve probably heard about the latest Biggest Loser (BL) study, which evaluated 14 participants from the TV weight-loss show long after their big weight-loss successes—six years later, in fact.

Sure, they had lost prodigious amounts of weight during the show—129 pounds, on average.

But six years later, they had regained an average of 90 pounds.

Even more disturbing, their resting metabolic rate—the baseline rate at which a body burns calories when not exercising—had dropped precipitously. Compared to before their weight-loss “success,” they now had to eat 500 fewer calories a day just to maintain their weight loss. No wonder they regained!

To add insult to injury, their appetite hormones were also out of whack. Leptin, which curbs feelings of hunger by producing a sense of fullness, averaged 41 ng/mL before the show, then dropped like a stone to 3 ng/mL when participants were starving themselves to lose weight…and six years later had risen back to a level of only 28 ng/mL.

In short, to sustain their substantial weight loss, they had to wage a never-ending battle with their own bodies, which were now able to gain weight on fewer calories—and always sending out hunger signals.

What does this tell us about dieting? Are all attempts at weight loss just doomed? Is it possible to avoid the mistakes of the Biggest Losers? Is it possible to lose weight and keep it off? For insight, we spoke with one of the world’s top obesity experts, Eric Ravussin, PhD, director of the Nutrition Obesity Research Center at Louisiana State University’s Pennington Biomedical Research Center.

Dr. Ravussin said there were seven important lessons that Bottom Line readers should take away from the problems caused by The Biggest Loser

  1. Willpower goes only so far. “You can’t blame obesity on sloth or gluttony,” said Dr. Ravussin. “Obesity is a disease.” Given the headwinds the Biggest Losers were pushing against, it’s amazing that they were able to sustain any weight loss. They may have problems, but willpower is not one of them.
  2. Extreme dieting wrecks metabolism—but more moderate dieting doesn’t have to. The Biggest Losers lost 40% of their body weight, on average, which led to extreme drops in their metabolic rates. “You can expect a huge drop in metabolic rate if you lose half your weight!” said Dr. Ravussin. “With a smaller weight loss, that wouldn’t happen.” To be sure, just about any weight loss drops metabolic rate—but usually much less so. “We’ve done a lot of these studies, and if you lose 10% of your body weight, your metabolic rate may drop by 50 or 100 calories per day.” That means that you’ll need to be vigilant about diet and exercise to maintain the weight loss—but it’s doable. (Fifty fewer calories is about five potato chips.) Losing 15% or more may increase the metabolic adaptation somewhat more, but many people have lost that much weight and kept it off, too.
  3. Gradual is best. To keep your metabolic rate from dropping too much, aim for weight loss of no more than one-half pound to two pounds per week. Said Dr. Ravussin, “To me the secret of weight loss is never to make it drastic.” In Dr. Ravussin’s studies, the weight loss was gradual.
  4. What kind of weight you lose affects how easily you’ll keep it off. To keep your metabolic rate from dropping too much, you want to hold onto as much “fat-free mass,” which includes muscle, as possible. One key is to make sure you’re eating enough protein. The other is exercise, both aerobic and strength training. Exercise won’t burn many calories when you’re trying to lose weight—a 30-minute brisk walk only burns about 200 calories—“but it’s a kind of protection against the loss of fat-free mass,” said Dr. Ravussin. Muscle burns many more calories at rest than does fat, so the more muscle you can keep, the higher your metabolic rate. In studies of people who’ve lost weight and kept it off, he said, “they’re very focused on exercise.”
  5. It’s normal to regain some weight—and that’s fine. No one would recommend the kind of extreme weight loss and then regain that the Biggest Losers experienced, but even they ended up a little healthier six years later. They were, on average, about 38 pounds lighter—11% below their pre-show weight. That’s enough to improve cardiovascular health, although it’s no argument for the Draconian program that wrecked their metabolisms. The point for the rest of us is that losing weight and then regaining some of it isn’t a failure—it likely means you’re healthier. “A weight loss of 5% to 10% of your body weight is a big metabolic health advantage,” said Dr. Ravussin. It’s linked with less insulin resistance and a healthier cholesterol level, and if you maintain it, a greatly reduced risk of developing diabetes. “If you can maintain a weight loss of 5% or 10%, it’s a winning situation.” More is fine if you can swing it, of course, but the biggest health benefits come from the first pounds off.
  6. For very heavy people—those with 100 pounds or more to lose—diet and exercise aren’t enough. “For the ‘morbidly obese,’ it’s totally unrealistic to try to lose this much weight through diet and exercise alone,” said Dr. Ravussin. “It’s like being jailed. The Biggest Losers, for example, were literally starving themselves to make the weight loss.” He believes they would have been better served with bariatric (gastric bypass) surgery, which studies show is not only associated with much less weight regain but with a metabolic rate that comes back almost to normal after about a year. For very heavy people who have been unsuccessful with weight loss through diet and exercise, said Dr. Ravussin, “gastric bypass surgery is one of the best solutions.”
  7. When it comes to achieving and maintaining a healthy weight, you’re never done. “It’s like taking medication to control your blood pressure—when you stop taking your meds, your blood pressure goes back up. Here, the medicine is lifestyle. One good thing about the study of the Biggest Losers is that it showed that it is indeed a struggle for many people to maintain a healthy weight. You have to change your lifestyle—and fight a toxic food environment where companies have become masters at making cheap food very palatable with fat and sugar. You have to keep at it!”