I Love Movies

I need someone to explain something...........See when a film is in the making, and they have a list of actors..lets say its a movie that has offensive lines in it..lets say about someones weight..a line in the movie like..your girlfriends a whale..or shes a bit too fat for my likes..and lets say the person playing the role isnt even like Fat Fat..like obese..say curvy or just bigger than the other characters..i wonder how they go about getting that person to play the role...like.."Oh by the way, i idea behind this movie is nobody wants to be with you cause you're fat..now dont take that personally..."and i think you match this role perfectly"..."are you calling me fat, you b*stard!!??".."NO, its just..ugh how can i put this??......how do they get an actor..(lets say female cause theyre more concerned with weight) to play that role..as the perfect person for it??...it sounds like an awkward process...basically your a top actor, sensational...but you are perfect for this character cause you're fat..Oooops!!...SLAP ACROSS THE FACE lolz