It's actually NOT inaccurate.  I looked for the guy's data...there was none.  He just FELT like that's how people should scale. ???? Meanwhile, in both Korea and the US, they used NHANES data (yes, South Korea does NHANES, too) to check BMI's correlation with body fat percentage across many different heights.  The traditional formula is actually extremely accurate.  It FEELS counterintuitive that it should be, but apparently taller people have disproportionately longer legs and arms and so their larger limb/trunk sizes is balanced out by that.  Interesting, no? When you check actual global variation of body weight with height, you find that taller people, on average, have a LOWER  traditional BMI than shorter people.  They also have a lower BF%, though, due to calorie access, TDEE variation, and unconscious social pressures (that encourage people to eat close to the same amount, regardless of body size/TDEE when eating together).