What is Obesity?

Obesity is a medical condition that results when a person has excessive body fat—to the extent that it negatively affects his or her health. The term "severely obese" refers to people who are severely overweight and at the greatest risk for developing major health problems.

You may be obese if you:

  • Are at least 20 percent heavier than the “normal” range for your height and age
  • Have a Body Mass Index (BMI)—a formula using height and weight to determine the amount of body fat a person has—that exceeds the “normal” range

You may be severely obese if you:

  • Are overweight by 100 pounds or more
  • Are 50 to 100 percent over the “normal” range for your height and weight
  • Have a BMI of 35 or more
  • Can’t function normally due to excess weight