The way I see it is that...I think the the reason why she keeps on demeaning herself so much is because she's criticising the character Britney not herself. But I do agree with you though. Cause she's extremely harsh to herself...The way she demeans herself is really sad.
She just got so used to being and getting called fat. Even though she's been working out, she's stuck in that fat mentality. Sometimes it takes a while for those (that were considered obese before) to even realize they're not overweight anymore. It's sadder to think how this wasn't her original body and how far this has affected her mentally. The way she's constantly down talks herself reminds me of what people with poor body image go through too.
i don't really like how she keeps calling herself a 'fatty'
i mean, ok it might not be your ideal weight and what you want for yourself, but you shouldn't degrade yourself like that
and for people reading that manga, especially in japan where it feels like they're really harsh on that, i feel like it wouldn't be a good influence for them
they'd think that fat is just always ugly and something to be ashamed