The Body Mass Index: the good, the bad, and the horrid

The Body Mass Index (BMI) was developed to estimate the risk for overweight in large samples of people from the wealthy, heavily industrialized nations of Western Europe and North America. When used for this purpose the BMI is, generally, a good tool to estimate overweight. The BMI is a bad tool when used to estimate fatness prior to the onset of the obesity epidemic in 1980 because BMI cannot distinguish between fat and lean tissue and there was, generally, lower levels of fatness in the general population before that date. The BMI is also a bad tool when used to estimate fatness for individuals in any nation or in any group of people. The BMI was never intended to be used for individual diagnosis. The BMI becomes a horrid tool to estimate fatness or health risk when used in some groups of people, such as high-level athletes, body building enthusiasts, people engaged in jobs with strenuous physical activity, and in groups suffering from the nutritional double-burden of very short stature with high body fatness.