Edgy romance movie

So I know most of the plot of this film, and a few memorable scenes, but for the life of me cannot remmeber the name. It’s a rather modern movie I think, probably post-2000. So, this girl is overweight and has dyed hair, green I think. And she meets this scrawny guy. They meet up at one of their houses, and the girl gives the guy a blowjob, and he immediately cums. Then she has to move away around the next day I think. They develop a long distance relationship. The guy works as a dishwasher so he can save up money to afford a plane ticket to see the girl. When he gets there, he’s weirdly disappointed, because she’s lost weight, and allowed her natural hair color to grow back in. She has a lot of new friends, and he’s basically resentful that she isn’t an outcast anymore. She makes her super buttery macaroni and cheese (I think) to try to make her fat again, and she gets really angry when she finds out. Then he tries to force feed the macaroni to her, and she totally hates him after that. At some point, the guy’s mom slaps him for being such an ass. Toward the end of the movie, a mutual friend of theirs ends up in the hospital, and they wordlessly reconnect after all the shit they went through in the movie.