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Obesity
What is it?
Obesity is another term for excess body fat. Normal body fat percentages range from 18%-23% in men and 25%-30% in women. Men with a body fat percentage greater than 25% and women with a body fat percentage greater than 30% are considered obese. Obesity occurs when intake of calories exceeds the daily caloric requirements. The National Institute of Health (NIH) classifies obesity as a chronic disease, which requires a lifelong effort.
Determining if an individual has excess body fat can be done by various methods. These methods include body density using underwater body weight, dual x-ray absorptiometry (DEXA), measuring skin-fold thickness, computed tomography (CT), and magnetic resonance imaging (MRI). The DEXA test and weighing an individual underwater are the most accurate methods, although they can be expensive, time consuming and are not always practical.
The two most common methods for measuring a person's excess body fat are "weight-for-height" tables and body mass index (BMI) measurement. The weight-for-height tables provide a range of acceptable weights for a person of a given height. There are many versions of these tables with different weight ranges, which limits their use. Because of variability of these tables, BMI has become the measurement of choice for many doctors and researchers. BMI is calculated using a mathematical formula that accounts for a person's height and weight. BMI is equal to a person's weight in kilograms (kg) divided by height in meters squared (BMI = kg/m2). To learn how to calculate your own BMI, click on the link at the bottom of this page.
For both men and women, the normal BMI is between 20 and 24.9. Individuals with a BMI of 25 to 29 are considered to be overweight. Individuals with a BMI of 30 or higher are considered to be obese.
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What is it?
