[Telepathic Intruder]

The reason, so I've read, that East Asians are smaller is because of their diet. While we in the west for millennia have relied mostly on wheat, they've grown rice, which is lower in nutritional value. You must eat a lot more rice to get the same benefit as wheat, but instead of growing more they just adapted and grew smaller themselves.

[9YearLurker]

There is that—plus different body proportions.

[Eagles6]

I've read that too.

Supposedly why Europe was more culturally and technically advanced too.

More protein in the diet makes for a stronger brain and body.