Font Size

Obesity (cont.)

Exams and Tests

Weight-to-height tables

These tables give general ranges of healthy weights and overweight for adult height. The tables do not take into account individual conditions. For one thing, they do not distinguish fat from muscle, water, or bone. They are much less helpful than body mass index in identifying risk of health problems related to weight.

Body fat percentage

Many health professionals agree that percentage of body weight that is fat is a good marker of obesity. Men with more than 25% fat and women with more than 30% fat are considered obese.

Body fat percentage is difficult to measure accurately, however. Special equipment is needed that is not found at most medical offices. The methods used at health clubs and weight loss programs may not be accurate if not done properly.

Waist measurement is also an important factor. People with "apple" shapes, who tend to put on weight around their waist, have a higher risk of obesity-related health problems. This includes women with a waist measurement of greater than 35 inches and men with a waist measurement of greater than 40 inches.

Body mass index

A measure called the body mass index (BMI) is used to assess your weight relative to your height. It is defined as weight in kilograms divided by height in meters squared (kg/m²). It can also be calculated for weight in pounds and height in inches.

Body mass index is closely related to body fat percentage but is much easier to measure. Therefore, it is used by many primary care providers to identify obesity. The greater your BMI, the higher your risk of developing health problems related to excess weight.

To calculate your body mass index, follow these steps:

Multiply your weight in pounds by 705
Then divide by your height in inches
Divide this by your height in inches again

What does BMI tell you?

Healthy = 18.5-24.9
Overweight = 25.0-29.9
Obese = 30 or greater
Morbidly obese = 40 or greater

To calculate your body mass index on the Internet, fill in your height and weight at the Web site of the government's National Heart, Lung, and Blood Institute's Obesity Education Initiative.