Some runners don't worry much about their weight. They think: I run, therefore I can eat a cow for dinner. However, these same runners will gain 3.3 pounds per decade, according to a recent analysis of 4,700 midlife male runners from the National Runners' Health Study. That's not a lot, but it does add up, and the gain strikes even those running more than 40 miles a week. The same runners also gained three-quarters of an inch around the waist every decade—goodbye six-pack abs!
I've always monitored my body weight closely, believing I have an American birthright to obsess over it, just like Oprah, Jared, and millions of others. I also figure there are two solid reasons to get on the scale every Saturday morning: I want to find and maintain my healthiest weight, and I also want to determine my fastest weight. I suspect I'm not the only runner who's interested in these two.
Twenty years ago, when reading some early studies on body mass index (BMI) and longevity, I cringed. People of my BMI—I'm relatively tall and skinny, with a BMI around 21.0—were dying younger than others a little heavier than I. (You can quickly determine your own BMI using our tool.)
On a recent visit to California, I visited Bill Haskell, Ph.D., to ask him about the weight and longevity question. He's a professor emeritus at Stanford University's Prevention Research Center and a guy who's been at the epicenter of important health-fitness debates for 30 years. "Those first studies failed to eliminate some people who were thin because they smoked cigarettes or were already diseased," Haskell told me. "The newer studies show no increase in mortality until BMI falls into the mid-eighteens."
The National Institutes of Health gives us four marks on the BMI ladder. It puts the underweight/unhealthy BMI cutoff at 18.5, which indicates malnourishment. If your BMI is 18.5 to 24.9, you're in the normal/healthy weight range. From 25.0 to 29.9, you're overweight, and your health risks (such as diabetes, high blood pressure, and heart disease) start climbing. Anyone above a 30.0 BMI gets labeled obese and faces dramatically higher health risks. Approximately 60 percent of all Americans are overweight or obese, and this percentage is increasing.
