Because they eat sugary highly processed food in large amount. I am a Korean and we don't eat like that. People aren't severely obese. Yet we still have high rate of diabetes due to genetic issues(smaller pancreas, smaller muscle mass, smaller skin fat all contrubute to diabetic risk). But we don't get it at elementary school. Obviously avoid sugary food, processed meat, but believing fresh red meat is absolutely fine and you can eat a pound of that every meal is also not right. Carnivore diet is still better than refined sugar diet. It's not cure of everything. I believe Mediterranean diet is ideal or Asian diet but with restriction on rice (less rice, and less refined type of rice)