Pacific Northwest | August 10, 2003Pacific Northwest MagazineAugust 10, home
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Compose Yourself
Measuring body fat is fine, but nothing to obsess over
The BOD POD, which measures body composition on the principle of air displacement, takes just a couple of minutes to run through.
I WAS STILL a good 10 feet from Dr. David Parker, a physiologist and executive director of the Washington Institute of Sports Medicine & Health in Kirkland, when he called out my body-fat percentage instead of saying hello. He nailed it.

Nice parlor trick, I told him.

"No trick," he replied, "I've just measured thousands of people."

The Centers for Disease Control and Prevention says most of us are overweight. The American Cancer Society released a study that states excess weight may contribute to 20 percent of all cancer deaths in women and 14 percent in men. Johns Hopkins University School of Medicine issued a report this year tying obesity to shorter life expectancy, especially in young adults.

In the eyes of fitness and health professionals, though, it isn't just how much you weigh that matters. It's what that weight is made of.

The more muscle tissue you have, the easier and faster it is to burn calories. When you lose weight simply by dieting, much of it, perhaps half, will come from muscle. It's not uncommon for someone to lose weight yet see his or her body-fat percentage ultimately increase. It happens in reverse, too. Sometimes people get discouraged because their exercise program doesn't translate into weight loss, but that might be because they are gaining muscle as they are losing fat. The other benefit to muscle is that it takes up less space.

There are several methods of measuring body composition, and I've tried many of them. All gave me different results, but only one was way off the mark, and that was likely operator and subject error. So if you use body-fat percentage as a way to track progress, pick one method and stick to it.

Minutes before meeting Parker, I got measured in the "The BOD POD," a windowed chamber shaped like a lima bean. It works on a principle of air displacement and takes only about two minutes. The machine's maker, Life Measurement Inc., touts it as the best combination of ease and accuracy. It's certainly easy, but the institute charges $50 for the first measurement and $35 after that.

I used a caliper from to pinch fat on my waist, chest and thigh. The caliper gives a digital readout from each spot, and then I do a little math to put the measurements in perspective. This method gave me my lowest fat measure, perhaps because of operator error. Caliper results vary depending on the accuracy of the pinch and experience of the pincher. I thought I'd cheated, so I had P.J. Glassey, owner of X-Gym downtown, do his caliper test. He made me at just 1 percent fatter.

Glassey also hooked me up to a few electrodes and conducted a "bioelectric impedance" test. This estimates your fat versus lean body mass by measuring the amount of water in your body. Muscle has a lot of water, fat has virtually none. The degree to which your body impedes the flow of current helps determine your body composition. This had me 2 percentage points higher. Yikes!

I tried a digital home scale, made by the Tanita Corp. (, that measured not only my total weight but also the percentage of it in fat. It uses the bioelectric-impedance method, and the one I got allowed me to store profiles for four people. This method isn't generally considered the most exact — if you're dehydrated it can send your "fat" reading rising — but it's very convenient, and I found myself measuring every day.

There are several other methods: being weighed in a pool, an MRI-like scan used in hospitals to calculate bone density, and ultrasound.

But whatever the method, Bob Weathers, professor of physical education and exercise medicine at Seattle Pacific University, warns that body composition should not be one more measurement to obsess over. Percentages can vary from method to method and mean different things to different people. In some cases, fatness might cloud the real problem — a poor lifestyle, diet and exercise habits.

Body-composition readings can also wake up thin people like me. Pat Hawley, the Northwest regional manager for Life Measurements, showed me photos of guys in Speedos to illustrate how misleading body types could be. Some thin men had higher fat percentages than some of the thick ones.

It also depends on where the fat is. Amassed around the middle — in proximity to organs — is considered most harmful.

So where should you be? Age, gender and other factors complicate the answer. If you do test, you will be given the grid of target areas for your profile. Generally, women average in the mid- to high-20s, but a good score for a woman older than 60 is 25 percent while 20-something women in good shape should be at about 17 percent. The rough average for men is 20.

Parker said he once measured a person with a body fat of 53 percent and another at about 2 percent. Neither level is healthy. Cyclist Lance Armstrong's is 4. Seems to work for him.

Richard Seven is a Pacific Northwest magazine staff writer.

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