Bathroom Scales Don't Tell The Whole Story
Experts rate the best and worst in body-fat measurement devices.
Also called hydrodensitometry testing, this involves getting into a tank
filled with water. Based on the amount of water you displace, your body density
and body fat can be calculated.
"This test is considered the gold standard, the most accurate assessment
technique," Bryant tells WebMD. Universities use this primarily with
athletes, and will likely let you try it, too -- for a small fee.
Price: $25 to $75 per test.
The verdict: "It's a very accurate way to measure body
fat," says Bryant. But going into the water can be a problem. Some find the
Grade: B-. Inconvenience is a big issue here, agrees
McCrory. "My guess is that underwater testing will be a 'has been' in a few
The Bod Pod is a new tool that relies on air displacement to determine body
fat, says Bryant. There's no submersion; you don't get wet. But you have to get
into the Bod Pod chamber, be very still, control your breath all factors that
can affect the results. Your hydration level before the test can also affect
results. "When all these are controlled pretty well, you'll get a body fat
calculation that's within 3% to 4% accurate not as high as one might
expect," Bryant says.
Price: $40 to $65 per test.
The verdict: McCrory says she believes it may be the way of
the future, though Bryant notes that it needs some refinement.
Grade: A. "It's much easier and more convenient than
underwater weighing," says McCrory. "It is about as accurate and
reliable as DEXA, is much cheaper, and is becoming more widely
The Tape Measure
It's one of the oldest "obesity tests" known to mankind. However,
waist circumference in this context "is not defined as a seamstress
would," says Bryant. "This is taken at the belly button level."
Men with measurements higher than 40, or women with waist measurements
higher than 35, are considered obese, he says.
The verdict: This is a basic indicator of a body fat
problem, says Bryant. "It's a good technique," says Kravitz.
Grade: A. Girth measurement is "accurate and
reliable" for assessing your risk of chronic diseases like diabetes, heart
disease, stroke, and cancer, says McCrory. Quite simply: The bigger the girth,
the bigger the risk. "However, some new research is coming out suggesting
that there is more risk than previously thought at even lower risk
Health clubs offer this test; it's the most widely used method for measuring
body fat, says Bryant. Basically, it's a "pinch" test using a measuring
device at several points on the body, like thighs, hips, and upper arm.
Price: $20 to $40 per test.
The verdict: Much depends on the skills of the person
giving you the test. "The skinfold test can be reasonably accurate,"
Bryant tells WebMD. "But if the tester isn't experienced, or if they're
using cheapo plastic calipers, take it with a grain of salt. It will be
Grade: D. "These are rarely done correctly," says
McCrory. "The technician usually does not grab enough fat so the result is
usually a big underestimate of body fat. It's also difficult to grab the fat