Beyond Pinching An Inch
How to Measure and Interpret Your Body Composition
By Suzanne Girard Eberle
As featured in the September 2000 issue of Running Times Magazine
Runners often struggle to accept the fact that being successful doesn’t hinge on registering the lowest possible number on the scale. In fact, many successful runners actually gain weight as they log miles and lift weights, even as they drop a clothing size or two. Feeling strong and running fast always are the best indicators that you’re at the "right" weight. Instead of battling the scale, you can keep tabs on your health—and possibly improve your performance—by focusing on body composition. Why Weight Doesn’t Really Matter. . .
Relying solely on a scale to evaluate your eating habits and training program has its limitations. For example, a scale can’t differentiate fat gained by overeating from muscle added as a result of training. In addition, our weight fluctuates from day to day, and even throughout the day. Daily weigh-ins indicate only shifts in body fluids resulting from sweat losses, hormonal changes and the carbohydrate content of meals and snacks. In addition, skimping on calories and shunning healthy foods is no formula for successful running. Rather, it sets you up for poor training, frequent illnesses and injuries.
. . . And Body Composition Does
Assessing the percentage of your body weight that is fat provides more useful information. Excess body fat can be unhealthy, as it increases the risk of heart disease, diabetes, high blood pressure and some cancers. Very few performance runners have body fat levels high enough to present a health risk, but see your doctor if you have concerns.
To function properly, our bodies need to store at least 5% fat for men and 8% to 12% for women. Average body-fat levels observed in elite runners range from 5% to 12% in men and 8% to 15% in women. A body-fat level below these recommended amounts can signal overtraining or the possibility of an eating disorder. The acceptable levels for the general population are 15% to 22% for men and 20% to 32% for women.
Can running performances improve with fat loss? Only to a point.
"I’ve counseled many coaches who bring athletes in, particularly female runners, who they believe need to lose weight," says Levi Query, an exercise physiologist and runner in Portland, OR, with 18 years experience evaluating athletes’ body composition. "A runner with a stocky build or one who carries most of her weight on the hips and thighs can appear overweight but actually be quite lean and muscular."
Keep in mind that runners perform successfully at a wide range of leannesses. One study of 70 elite women distance runners found their average body fat was 16.8%, with a range of 6% to 35.8%. The goal is to determine a range at which you feel and perform best, not to chase after a specific value. For most runners, monitoring body composition a couple of times a year is sufficient.