I don’t understand the justification for the Body Mass Index (BMI). I guess they’ve found a strong correlation between BMI and body fat percentage, and the correlation is the most important thing. But I don’t understand the units. It’s measured in kg/m2. Wouldn’t kg/m3 be more logical? Are we supposed to be two dimensional?
This scale would give the same score to a five-footer and a six-footer who weighs just 44% more (62/52). I would expect that the logical equilibrium point would be 72.8% more (63/53.) I know that children are treated somewhat differently, but in the existing scale, a 25-pound three-foot tall child would scale up to a six-foot tall adult weighing only 100 pounds.
(For those with more logical measurement scales, 2.2 pounds = 1 kilogram, and 1 foot = 12 inches = 30.48 centimeters.)
I can find many BMI calculators online, and some medical references to the relationship between BMI and body fat percent. But nothing explains why the units are in mass/height2.
Update: A more recent entry notes that the use of the BMI by medical professionals is being eliminated.