"I don't understand your choice to be a fat lady, your choice to dress in unflattering styles. And I find it disturbing, even distressing. Why these self destructive choices? Why are punishing yourself? Do you think you don't deserve the happiness of being fit and healthy? Of being the pretty woman you could easily be? I'm sorry, but it's harder and harder to be comfortable around you. If you were trying to change, I'd be right behind you, be your biggest cheerleader. But your determination to be a fat slob is getting in the way of my caring about you. We may be seeing less of each other until you decide to start making better choices."
I very much disagree with the idea that if Fatty is OK with being fat, then I should be OK with Fatty being fat. Maybe Fatty is OK with being fat, but I'm not OK with Fatty being OK with that. I think we have a responsibility to our families and our communities and to ourselves to avoid self destructive behaviors. Would I be OK with Druggie being OK with her addiction to cocaine? With Cheater being OK with his cheating? Of course not. And neither am I OK with Fatty being OK with his/her choice to be fat.
Yes I know some people have metabolism problems, other physical problems that make them fat. But almost always a fatty is fat because of eating too much and moving around too little, not because of medical problems.