Using a formula to calculate obesity is not a new concept. In the nineteenth century, a Belgian statistician named Adolphe Quetelet came up with the Quetelet Index of Obesity, which measured obesity by dividing a person's weight (in kilograms) by the square of his or her height (in inches).
Before 1980, doctors generally used weight-for-height tables -- one for men and one for women -- that included ranges of body weights for each inch of height. These tables were limited because they were based on weight alone, rather than body composition. BMI became an international standard for obesity measurement in the 1980s. The public learned about BMI the late 1990s, when the government launched an initiative to encourage healthy eating and exercise.
In 1998, the National Institutes of Health lowered the overweight threshold for BMI 27.8 to 25 to match international guidelines. The move added 30 million Americans who were previously in the "healthy weight" category to the "overweight" category. Today, the NIH advises doctors and their patients to include BMI in a complete assessment of a person's body size and overall health.
For more information on BMI and related topics, check out the links on the next page.