@Pokari Are we even reading the same story? Only the main character is viewing her fatness as an issue. Once the MC became a better person, everyone started to like her despite her being fat.
The boy that once rejected her is falling for her WHILE she is fat.
The negativity towards being fat is HER OWN self image. Not other people's.
This novel did not ONCE treat fatness as the real problem. It was just ONE of the problems and it was the least important one. It was just personally more important to HER (you know, a girl worried about her self image).