This is 19 year-old Kanna Motoyoshi. She got into cosplay as a way to show her love for anime character Tieria Erde from Mobile Suit Gundam 00. Not everyone was so receptive, however.
Kanna didn't always look like this. For example, in junior high school, she weighed around 176 pounds. As the screenshot says, this is an actual pic of her from that time:
A huge fan of Tieria, she decided to go to an anime event dressed as the character. Here is a dramatic recreation of the event with an actor playing her. The show's depiction was hardly nuanced — note the bandanas, which are a stereotypical otaku, or "geek," trope in Japan:
At the event, Kanna was mocked, with people saying things like, "What's that? Who are you supposed to be cosplaying as?" [Photo: /akanenene000]
Then, she looked at herself in the mirror. [Photo: Eva08Ke]
The subtitle says something like, "Just a fatty looking weird." Eh... [Photo: Shining Finger]
And after that, she wondered if she wasn't bringing shame to the anime character Tieria — causing people to laugh at the character. On the show's dramatic recreation, Kanna then apologized to Tieria. Why can't the jerks who made fun of her apologise? [Photo: mocarain]
After that, she put the character's cards where snacks were kept because...Tieria is always watching. [Photo: Megane_89]
And the result was, according to the show, that Kanna went from 209 pounds to 99 pounds, losing over a hundred pounds. [Photo: yuikatto3414]
The show visited her at home and showed off her stomach. [Photo: Yaraon]
She seems so happy! [Photo: har10b]
Look, people should be able to do what they want. If someone wants to cosplay as a certain character, and their body (or skin colour or gender or whatever!) isn't an exact match, who cares. They shouldn't be made to feel bad about that.
And if somebody wants to lose a lot of weight (though, this certainly seems extreme), that's their decision. However, they shouldn't feel compelled to do so to meet preconceived notions that other people have or unrealistic artistic renditions. They should do it for themselves.