The Unbearable Lightness of BMI
KIEL – Now is the time of year when many people most dread stepping onto the bathroom scale. But, while all of that holiday feasting may have led to greater girth, how should we understand what higher or lower body weight means?
The body mass index (BMI) has long been used in epidemiology, medicine, and nutritional sciences. But its value is increasingly being questioned, especially in obesity research, where body-composition measurements are proving to be far more relevant.
The BMI is calculated by dividing a person’s body weight in kilograms by the square of his height in meters (kg/m2). First named after the Belgian astronomer, mathematician, and statistician Adolphe Quetelet, who demonstrated in 1835 how adult weight normally increases in proportion to height squared, the index provides a measure of body weight, independent of stature, allowing us to compare the weight of short and tall people.