All you have to do is wheel your grocery cart into a checkout line to see the cautionary tales screaming at you from the tabloids:
Kirstie Alley regained the 70-plus pounds she lost on Jenny Craig. Maureen "Marcia Brady" McCormick got even heavier after she was on Celebrity Fit Club. Oprah, well, we all know about her struggles. Janet Jackson, Kelly Clarkson... the list goes on and on.
It makes you wonder: If these rich, powerful women, with their personal trainers and private chefs, can't win the weight war, what chance do I have?
It doesn't help that the statistics are grim: By some estimates, more than 80 percent of people who have lost weight regain all of it, or more, after two years. Researchers at the University of California at Los Angeles analyzed 31 long-term diet studies and found that about two-thirds of dieters regained more weight within four or five years than they initially lost.
Women who want to lose weight know these painful numbers all too well. "I've been on a roller coaster for the past two years," says Leigh Moyer, 31, of Philadelphia. In 2003, she lost 25 of her 155 pounds by diligently counting calories and logging daily sweat sessions at the gym. Four years later, busy with graduate school and her job at a software company, Leigh blew off her workouts and stopped monitoring her portions... and shot up to 175. "It was so sad, so frustrating," she says. "I let myself down."
Along with the emotional toll is a physical one: Not only is the extra weight a health risk, but recent studies have linked the gain-lose-gain cycle to such potentially life-threatening conditions as high blood pressure, high cholesterol, diabetes, depression, heart disease, and cancer.
Understanding metabolic math
While small fluctuations on the scale are normal, the unhealthy behavior that experts refer to as "weight cycling" is not. Cycling is defined as a significant increase or decrease of body weight (generally 10 pounds or more) that occurs multiple times.
Experts believe a yo-yo pattern is often the result of a diet that's too restrictive, and a study reported in the journal Obesity backs that up: It found that people who followed a very low-calorie diet regained significantly more weight than those on a more forgiving plan. Desperate for quick results in a culture of instant gratification, "women try to lose weight on diets with too few calories," says Judith Beck, Ph.D., director of the Beck Institute of Cognitive Therapy and author of "The Beck Diet Solution." "If you lose weight on 1,200 calories a day, the minute you go up to 1,300 is the minute you start gaining weight."
It happened to Tracy Srail. The 24-year-old from Atlanta has watched the scale bounce between 130 and 160 pounds for the past four years. "At one point, I was eating only one or two meals a day and chugging Rockstar energy drinks because I heard that caffeine increases your metabolism. I lost 15 pounds, but it didn't stick," she says. "I weigh about 155 now."
Even on a sensible diet, your body sheds pounds reluctantly. "One reason it's difficult to keep weight off is because there is a metabolic overcompensation for weight loss," says Gary Foster, Ph.D., director of the Center of Obesity Research and Education at Temple University in Philadelphia. "If you decrease your body mass by 10 percent, you would expect your metabolic rate to decrease by 10 percent, but it actually slows down more than that, by about 11 to 15 percent."
Why does your own metabolism thwart you? Simple, says Kelly Brownell, M.D., director of the Rudd Center for Food Policy and Obesity at Yale University: "The body may perceive dieting as a threat to its survival. It might not know the difference between Atkins and famine."
What's more, says Brownell, who coined the term "yo-yo dieting" in the 1980s, weight cycling can actually change your physiology. So the more diets you've been on, the harder it becomes to lose the weight. A hunger hormone called ghrelin increases, and a fullness hormone called leptin decreases, so you feel hungrier and less satiated.
Born to rebound?
It's bad enough that your body fights you when you try to lose weight. Now there's compelling research to show that some people may be hardwired to yo-yo.
David Kessler, M.D., former U.S. Food and Drug Administration commissioner and author of "The End of Overeating," and his team of researchers at the University of California at San Francisco and Yale University, looked into the biology of weight cycling. They found that the reward circuits in the brains of people Kessler calls "conditioned hypereaters" were excessively activated simply by the smell of food and stayed that way until those people finished eating whatever was on the plate in front of them.
In other words, when you have overactive neural circuitry, resisting temptation is not a question of willpower alone. "This is a biological cause of conditioned hypereating. It's the first time we can say 'It's not your fault,' " Kessler says. He estimates that 50 percent of obese people and 30 percent of overweight people are conditioned hypereaters.
Evidence shows, however, that this reaction is partially learned, and that through conditioning, you can rewire your brain. After all, the yen to yo-yo is not just physical; emotional triggers play a huge role too. A study at Brown University found that dieters who ate in response to emotions such as stress or loneliness — as opposed to external events, like overdoing it at happy hour — were more likely to regain weight.
When Darcie Schmidt of Sioux Falls, South Dakota, was in her late twenties, she lost 75 pounds and then regained 120 over two years, largely because of emotional eating, she says. In her early thirties, she stuck to a strict diet-and-exercise regimen and shed 132 pounds. "I did not eat a single chip for 18 months," she says. But the stress of a divorce, a move, and a return to school knocked her off track, and she traded her three-mile, five-day-a-week runs for bags of those verboten chips — and regained 40 pounds.
Beck sees women like Schmidt all the time, who do well for a while, only to fall off the wagon. The problem, she believes, is that they never learned the skills needed for long-term behavior change. "They haven't been taught how to motivate themselves every day," Beck says, "or how to respond to negative thoughts and recognize a mistake as a one-time thing."
A study of 200 overweight and obese people, published in the Journal of Psychosomatic Research, supports the importance of a behavior-change approach. Along with other weight-loss techniques, one group received an additional hour of therapy, in which they learned to change their behavior; the other group did an extra hour of low-intensity exercise. After a year, those in the therapy group had maintained their weight loss, while the other group's members hadn't.
While watching the numbers on the scale fluctuate wildly is a blues inducer and clothes-budget buster, there are far more compelling reasons to hold steady. For one, your metabolism might be affected — and not in the way you probably hoped.
"If you go on a very strict diet and gain the weight back quickly, you might lose a lot of muscle and regain a lot of fat," says Keith Ayoob, M.D., R.D., an associate professor at the Albert Einstein College of Medicine. "Then your metabolism operates on a slower idle, which means it's going to be harder to lose weight as time goes on."
The more times you yo-yo, the theory goes, the more fat your body gains in each rebound. Because muscle burns 10 times more calories than fat does, your metabolism eventually will slow to a crawl.
"Losing and gaining regularly takes a huge toll on your body," Ayoob says. Beyond aesthetics, such as a loss of skin elasticity, regaining weight burdens your arteries and skeletal system, and may stress the liver, which can become covered in fat.
Yo-yoing also does a number on your ticker: A study in Clinical Cardiology found that women who weight cycle five times or more during their lifetimes may be damaging their hearts in the process.
But perhaps most startling is the dangerous and lasting effect weight cycling has on the immune system. According to the first study of the long-term impacts of yo-yo dieting, women who repeatedly lost and gained weight had lower immune function, particularly lower counts of natural killer cells. "These cells are important for fending off infections and are also vital in fighting the early stages of cancer," says Cornelia Ulrich, M.D., of the Fred Hutchinson Cancer Research Center in Seattle. Low killer-cell activity is associated with higher rates of cancer. In her study of more than a hundred overweight but otherwise healthy women, those who had yo-yoed most frequently — five times or more — decreased their natural killer-cell activity by a third.
With so many drawbacks, you might wonder if you'd be better off just accepting your belly rolls. But the perils of being overweight still outweigh the risks of yo-yoing. So how do you quit the cycle for good? Despite what you read in the tabloids, it is possible.