I quit therapy because, like you, i found the therapist wanted to work on goals SHE had for me -- not the goals *I* set. And, of course, the thing she wanted to work on was that i'm fat. So original.

I think if you've worked and worked on an issue and decided it's futile, people should respect that. It doesn't sound like your mom is gonna change and that you've made a good effort to improve things without success. Limiting your exposure to her sounds like a good strategy to me.