Use and Misuse of BMI Categories

Body mass index (BMI) was introduced in the 19th century as a measure of weight relative to height. Before the late 20th century, overweight and obesity were not considered a population-wide health risk, but the advent of new weight loss drugs in the 1990s accelerated the medicalization of BMI. A BMI category labeled obesity was adopted in 1997 by a World Health Organization consultation and subsequently by the US government. Language in the National Coverage Determinations Manual stating that "obesity itself cannot be considered an illness" was removed in 2004, allowing reimbursement for weight loss treatments. In 2013, the American Medical Association declared obesity to be a disease. Yet the focus on BMI categories and on weight loss has yielded few health benefits and contributes to weight-related discrimination and other potential harms.