From what I could tell and the food items that they have shown, her friend pushed her down to a diet system aswell as working out. She was never starved but rather ate portions which were controlled and not excessive. She was beautiful as a person, however, physically was out of control and her body weight was not good. No matter how you look at it, (personally, i think everyone can work themselves to have their own appropriate bodies), she just wanted to be more appealing to Osamu. Like how a guy will work out and train muscles since its more appealing than having a beer belly. She didn't starve herself is my point, she stopped eating the excessive amount she used too which was a bad habit and is what the friend reminded her off. Also to not let her waste her efforts and struggles to relapse.
i feel like she did help tho because lets be honest that kind of body isnt healthy and she already warned her about it being hard if she really want to achieve the body that she wants. i think she was just helping her being more healthy?
Don't you guys think that her friend literally gave her an eating disorder and is always telling her to not gain weight again and that she was ugly then and that if she wanted to pull the director (at the beginning) she would have to lose weight so that he can like her