[fallingsquirrel]

That isn't a change of physiology, it's a change of our external environment. AFAIK there's no evidence to show humans living 100 years ago would respond any differently to modern nutrition than we do.

If the cause of being taller were internal, such as genetic changes: that would be a change in physiology.

[Izkata]

There are only two inputs to BMI, and height is one of them.

[fallingsquirrel]

That's a complete non-sequitur. If you cut off your feet and get shorter, it doesn't mean the human species has physiologically changed. And if you eat more calories and get taller, it doesn't mean the human species has physiologically changed.

[s1artibartfast]

Yep, and it's not like there is a mysterious lack of cardiovascular and health consequences that would make us question the belief that high BMI is bad

[Izkata]

Even that is relevant, because it would mean the measurement is now wrong.