Can You Be Fat But Fit?
How Fat and Weight Affect Your HealthThe Skinny on Fat
None of this is to say that we can pack on pounds without worry. Carrying a lot of weight around increases stress on joints and can make us less inclined to be active. There's also the plain reality that the more overweight you are, the more likely it is that your metabolic health will take a hit, now or in the future. "Given the choice, I come down almost always on the side that being overweight is a bad thing," says Walter R. Thompson, PhD, a professor of exercise science at Georgia State University in Atlanta.
But choice is a loaded word for many obesity experts, as well as for countless individuals who have waged a lifelong war with their weight. "I spent the first part of my life struggling with being fat. I would lose weight on diets, gain it back, and each time end up feeling horrible about myself," says Hanne Blank, the author of The Unapologetic Fat Girl's Guide to Exercise and Other Incendiary Acts. "Only as I've come into my own as an adult have I made peace with the fact that I may always be big." It's a brutal realization that seems to bear itself out in the big picture: As many as two-thirds of us end up regaining more weight than we lose while dieting.
Pinning ambitious weight-loss hopes on exercise hasn't panned out too well, either. At five feet four inches and 172 pounds, Sherry Norris, 42, of Norcross, Georgia, knows this firsthand. A dedicated exerciser, Sherry alternates running and working out to the Insanity DVD program on most days and ran her first marathon last year. "I've followed all the directions and done the training plans, and I've lost exactly five pounds. At this point I have no idea how to get the weight off," she says.
Within the past few years numerous studies have borne out exactly what Sherry is experiencing: Despite the extra calories we burn, many of us fail to lose weight -- and may even gain some -- after embarking on an exercise program. This could be because our appetite is triggered by vigorous activity; we reward ourselves for our efforts with food, or we spend more time vegging out on the couch when we're not at the gym.
Then there's the tricky topic of metabolism. "Exercise doesn't rev up the metabolism, as we've been led to believe," says Diana Thomas, PhD, an author of a study from the Center for Quantitative Obesity Research at Montclair State University in New Jersey. "We found that when volunteers who were put on an exercise regimen began to lose weight, their metabolic rate -- how many calories they would burn while sitting and doing nothing -- actually began to drop." Thomas and her colleagues suspect that metabolic slowing may be the body's protective attempt to preserve energy when it senses that more calories are being burned through exercise. Plus a fit body operates more efficiently -- the heart doesn't have to pump as fast, breathing is less rapid -- and that also reduces how many calories we burn all day.
Making long-term weight loss even more elusive is the fact that we each may have our own personal set point, a range of about 10 to 20 pounds in which the body biologically tries to stay despite our efforts. This means that weight loss is biologically resisted in some people. Also, our appetite makes it too easy to override the upper threshold of our set-point range, so we gain weight, says Linda Bacon, PhD, the author of Health at Every Size: The Surprising Truth About Your Weight.
The net result of these many hurdles: Even if people do lose some weight from exercise, they often don't lose as much as they expect to. For many, that's reason enough to abandon boot camp and head back to the couch.Eyeing a Different Prize
That, Thomas says, is a crying shame. Because even if pounds don't disappear, a big fat change is probably taking shape. "Adding regular physical activity can reduce the proportion of fat to muscle and affect where fat is distributed," Thomas says. In particular, as little as a 20-minute daily walk can reduce the amount of visceral fat that reaches deep into the abdomen. That's the fat that health experts worry about, because it is linked to heart disease, diabetes, and a higher mortality rate. There's even evidence suggesting that exercise stimulates the production of a substance called irisin in muscle tissue. This hormone appears to transform white fat cells, like those in belly fat, into brown fat cells, which are metabolically active and actually burn calories.
"The scale doesn't necessarily reflect all of this," Thomas says. Neither does the body mass index (BMI), which uses only height and weight to estimate how much body fat we ostensibly have. This is why a growing number of doctors are now measuring patients' waist circumference as part of their standard physical exams. And it's why Thomas and colleagues at Pennington Biomedical Research Center in Baton Rouge, Louisiana, have devised an index that takes body shape into account when assessing a person's health. The body roundness calculator (pbrc.edu/bodyroundness) uses hip and waist measurements in addition to weight and height. The closer to a circle shape a person is, the more visceral body fat she has. "We're catching people who are out of the 'safe shape' zone but who are not visibly apple shaped. There are also people whose BMI may indicate obesity but whose body roundness is healthy. It's a much better reflection of a person's health overall," Thomas says.
What do you think of this story? Leave a Comment.