What is Overweight?

Obesity is an excess proportion of total body fat. A person is considered obese when his or her weight is 20% or more above normal weight. The most common measure of obesity is the body mass index or BMI. A person is considered overweight if his or her BMI is between 25 and 29.9; a person is considered obese if his or her BMI is over 30.

"Morbid obesity" means that a person is either 50%-100% over normal weight, more than 100 pounds over normal weight, has a BMI of 40 or higher, or is sufficiently overweight to severely interfere with health or normal function.

The Body mass Index
The body mass index (BMI), or Quetelet index, is a statistical measure of the weight of ax person scaled according to height. As such, it is useful as a population measure only, and is not appropriate for diagnosing individuals. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing "social physics"
Body mass index is defined as the individual's body weight divided by the square of their height. The formulas universally used in medicine produce a unit of measure of kg/m². Body mass index may be accurately calculated using either of the formulas below.