Body Fat Measurement: Percentage Vs. Body Mass (cont.)

You're probably familiar with body mass index. BMI is an equation that gives you a numerical rating of your health based on height and weight. As your BMI goes up, so does your risk of developing weight-related diseases, such as heart disease and diabetes.

But even as more and more people are using their BMI number as an indicator of overall health, research on fat percentage is improving.

In September 2000, the American Journal of Clinical Nutrition published a study showing that body-fat percentage may be a better measure of your risk of weight-related diseases than BMI. Steven Heymsfield, MD, director of the Obesity Research Center at St. Luke's Roosevelt Hospital in New York, and his colleagues evaluated more than 1,600 people from diverse ethnic backgrounds. Researchers took body-fat measurements and studied how their body fat related to disease risk.

"Many studies have related BMI to disease risk," noted Heymsfield. "What we did was correlate body-fat percentage to BMI, allowing us to take the first big step toward linking body-fat percentage to disease risk. This new research reveals the value of assessing body fat more directly using the latest scientific technology to measure body-fat percentage," he added.

Although several research studies have indicated that an elevated BMI is associated with heart disease, stroke, type 2 diabetes and some cancers, BMI does not distinguish fat from muscle.

"If we think of BMI being a rough measure of body fatness, there are people -- especially some highly trained athletes -- who are overweight but not overfat," says Heymsfield. "Likewise, there are people who are of a normal weight according to BMI scales but who are overfat. BMI is a broad, general measure of risk. Body-fat assessment is much more specific to your actual fat content and thus provides a more accurate picture."

"Not all measures of fat percentage are equal."

How Much Fat is OK?

The American Council on Exercise provides the following ranges for body-fat percentage:



Essential fat













32% plus

26% plus

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