Why does CDC use the Body Mass Index (BMI) to measure overweight and obesity in the general adult population?
Calculating the BMI is one of the best methods for population assessment of overweight and obesity. It is low-cost and easy to use for clinicians and the general public. The use of BMI allows people to compare their own weight status to the general population. The only information required to calculate a person’s BMI are height, weight, and the BMI formula
|BMI = (|| Weight in Pounds
(Height in inches) x (Height in inches)
|) x 703|
|BMI =|| Weight in Kilograms
(Height in Meters) x (Height in Meters)
What are some of the other ways to measure obesity? Why doesn’t CDC use those to determine overweight and obesity among the general public?
Other methods include calipers (skin-fold measurement), underwater weighing, bioelectrical impedance, and computerized topography. However, these methods are very expensive, need highly trained personnel, and are not readily available to the public or general clinical settings.
Are athletes and other people with a lot of muscle considered to be overweight when their BMI is over 25?
According to the weight categories, any person with a BMI over 25 would be classified as overweight. This may not mean they have excess fat. Such categories are based on scientific findings that the risk for disease increases as BMI increases.
Most studies have examined the relationship between BMI and risk of disease. Therefore we do not know whether two people with the same BMI but different amounts of fat have different risks for disease.
It is important to remember that weight is only one factor related to disease. If you have questions or concerns about the appropriateness of your weight, please discuss them with your health care provider.
How is BMI interpreted differently for children (2 – 20 years) than adults?
BMI is calculated with the same formula for children and adults, but the results are interpreted differently. For adults the use of BMI to define overweight does not depend on age or gender. For children ages 2 – 20 years, BMI is plotted on a growth chart specific for age and gender. For additional information on the 2000 CDC Growth Charts please visit CDC’s National Center for Health Statistics.