Bullying is more about physical abuse or harassment I think. People staring and laughing about you? Duh.

So fat is positivity?

So she should be comfortable being overweight? Being unhealthy?

“Did something really unhealthy”

How are you judging this? With your country’s health standard? I’m happy that you worried for her, but note that asian girls typically stands around 150-160cm. 80kg is a really, REALLY overweight for that frame. Normal weight would be around 50-60. To be honest 60 is already pushing it.