The body mass index (BMI), or Quetelet index, is a heuristic measure of body weight based on a person’s weight and height. Though it does not actually measure the percentage of body fat, it is used to estimate a healthy body weight based on a person’s height, assuming an average body composition.
Due to its ease of measurement and calculation, it is the most widely used diagnostic tool to identify weight problems within a population, usually whether individuals are underweight, overweight or obese. 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 his or her height. The formula universally used in medicine produce a unit of measure of kg/m2. BMI can also be determined using a BMI chart, which displays BMI as a function of weight (horizontal axis) and height (vertical axis) using contour lines for different values of BMI or colors for different BMI categories.