HEALTH TOPICS 
Obesity
What Is It?
Obesity is an excess of body fat.
It is difficult to directly measure body fat. Body mass index (BMI) is a popular method of defining a healthy weight. BMI should be used as a guide, along with waist size, to help estimate the amount of body fat.
BMI estimates a healthy weight based on your height. Because it considers height as well as weight, it is a more accurate guide than body weight alone.
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