I eat all the time. I run hot. I also fat. I also think BMI is not a good measurement, not just because it says I'm morbidly obese, but also because it skews in favor of those with smaller frames for their height.
BMI seems to be one of those things that everyone in the relevant field knows is pretty damn bad, but no consensus has formed around anything better so they keep using it anyway. (I'm sure there are parallels to things in the software world - SQL comes quickly to mind - but that's a bit OT so I'll resist the temptation to explore that idea further.)
BSA (DuBois method, usually) is more common (and considered a better measurement) outside of the states and is more accurate for folks outside of the "average" range. BMI is probably so popular because of how simple the formula is, compared to something like BSA