The ABCs of BMI
The Body Fat Index (BMI) is the percentage of fat that your body contains. For your body to function properly it is essential that your body contains a certain amount of fat. Body fat helps regulate your body temperature, it cushions and insulates organs and is the main form of the body's energy storage. It is important for everyone to have a healthy amount of body fat.
The amount of body fat that you do or do not have can be potentially dangerous to your health. Too much body fat increases your risk of high blood pressure, high cholesterol, heart disease and more. Too little body fat deprives your body of stored energy, protection for your organs and can potentially cause your body to enter a state of catabolism, which is when your body begins to use muscle protein as fuel.
Your body fat percentage is calculated by taking your age, height and weight, gender and waist measurement into account. Use a body fat calculator to determine your body fat percentage for you. Your results will help you determine a healthy and realistic weight loss goal based on the information you provide.
While the right BMI varies from person to person, depending on your age and other factors, this chart from the American Council on Exercise (ACE) is commonly used.
Description Women Men
Essential fat 10-13% 2-5%
Athletes 14-20% 6-13%
Fitness 21-24% 14-17%
Average 25-31% 18-24%
Obese 32%+ 25%+
"Essential fat" is the minimum amount of fat necessary for basic health. There is a lot of controversy over what amount of body fat is optimal for overall health. A recent research paper came to the conclusion that certain low body fat ranges are "underfat," which implies "unhealthy." According to this paper, men who are between 20-40 years old with under 8% body fat are considered "underfat," whereas a "healthy" range is described as between 8-19%. For women in this same age group, any level under 21% is "underfat" and 21-33% is considered "healthy."