Issue 129 Item 4 Excess Fat Can Cancel Benefits of Exercise

Weight still matters, even if you put in time at the gym and are fit. A subject of an ongoing debate among health experts is: does it matter if you’re carrying around excess fat as long as you’re fit,? Now a new study says that weight matters, even if you put in time at the gym.

Regular exercise does not cancel out all the health risks of being overweight, according to study results in the TK issue of the American Journal of Epidemiology. It’s the normal-weight people who are in shape who can expect to live the longest.

"It is important not to be overweight, but it also important to be fit," said study author Dr. June Stevens, a professor of nutrition and epidemiology at the University of North Carolina in Chapel Hill. "Just being slender is not enough. Just being fit is not enough. In order to enjoy the best life expectancy, you need to be both."

The new findings are based on data from 2,506 women and 2,860 men in eight U.S. cities who participated in a study that began in 1972, when their average age was about 45. At baseline, subjects had their fitness levels assessed by treadmill tests and their body mass index — a standardized measure that takes into account height and weight – calculated. Subjects were grouped into the following categories: fit, not fit, fat and not fat. They were followed until 1998. [abstract]

In both women and men, the unfit-fat group faced the greatest risk of death. But while exercise helped boost longevity in the overweight group, it did not erase all the negative effects of the excess weight. Likewise, people who were thin but unfit also faced a shortened life span, results showed.

Compared with the fit-not fat women, the increased risk of death was 32% among the fit-fat women, 30% among the unfit-not fat women and 57% in the unfit-fat women. [p. 838, figure 2]

Similarly, compared with the fit-not fat men, the increased risk of death was 25% among the fit-fat men, 44% in the unfit-not fat men and 49% in the unfit-fat group. [p. 838, figure 3]

The findings underscore the importance of both maintaining a healthy weight and getting regular exercise. But for people who exercise regularly yet still can’t seem to shed those extra pounds, don’t give up. "Keep exercising," she said. "And if you can’t lose weight, work hard not to gain [more] weight." American Journal of Epidemiology 2002;156:832-841.