Kate Harding at Shapely Prose has put together a slide show which demonstrates the vast stupidity of BMI. It’s quite long (45 slides), but you don’t need to watch the whole thing to get the point.
Meanwhile, The Rotund offered “guess my height and weight,” and then provided really cool graphs of the responses. What she proves without question (which most fat people already know) is that very few people know how big 200, 300, or 400 pounds are–and even when you do know in general, weight distribution makes guessing very complicated.
Even though one picture is worth a thousand words (and thus Kate’s slide show is worth 45,000 words and The Rotund added another thousand), I can’t resist adding a few words of my own.
BMI, which is almost universally accepted in the United States, and much of the rest of the world, has no medical history. It was invented by Adolphe Quetelet, a Belgian statistician, and it was adopted without question or examination by the medical profession. It is in no way a medical concept. In fact, the result of our best existing study on BMI and health caused the CDC to drop its estimates of death caused by obesity from 400,000 per year to 25,000 per year.
BMI is “body weight divided by height squared,” which makes it even less useful for short people than it is for anyone else. As you will see from the slide show, it does not take muscle mass into account. Most professional football players are “morbidly obese” by BMI standards. It is completely blind to measures like exercise levels, heart rate, etc. Some efforts have been made to incorporate age (i.e., to have different measures for children), but they are not especially widely accepted and, like the simple form of BMI, no external factors are included.
Frankly, BMI is roughly as useful a medical concept as “the vapors,” or “hysteria.” It would be funny if it wasn’t so frequently used as a weapon against all of us. Our best hope is that these projects will help drive some much-needed nails into BMI’s coffin.