Fat Poses Risk Regardless Of Fitness, Study Says

Overweight women who exercise may be at greater risk for heart attack than thin women who are sedentary, though a study called both excess weight and inactivity risky. (By William Thomas Cain -- Getty Images)

Is it okay to be fat but fit?

With the number of Americans who are overweight on the rise, health experts have been debating whether it's possible to be both fat and healthy. Some experts have argued that being unfit is actually worse than being fat, and that fat people can be healthy as long as they are fit.

A large, new study undermines that argument, concluding that while both fitness and fatness are important, no amount of physical activity can completely erase the risks of being overweight.

Researchers at Brigham and Women's Hospital in Boston measured a variety of risk factors for heart disease among more than 27,000 healthy middle-aged women participating in the ongoing Women's Health Study.

Being either overweight or inactive each independently raised risk factors for heart disease, the researchers found. While women at any weight reduced their risks by exercising, being overweight appeared to be worse than being inactive, the researchers found. Even thin couch potatoes had lower risks than active women who were just a little overweight, the researchers found.

But that doesn't mean being thin is enough, the researchers warned: Thin women who do not exercise still face an increased risk of heart disease -- the leading killer of women.

"We don't want women to get the idea that it's okay to be a couch potato just because they are thin," said Samia Mora, who led the study, being published today in the Journal of the American Medical Association. Mora noted that women with the lowest risk were those who were both physically active and of normal weight.

"The message should really be to get out there and be active no matter what you weigh, even if it's just for 30 minutes a day," she said. "Both are important."