Personally, I don't know how anyone can claim to accept themselves in a state that renders them non-functional.
In my mind, it's not a question of attractiveness... I see many women larger than myself every day, that I think are objectively more attractive than I am. However, the fat acceptance movement seems to be more about embracing actual obesity than simply just body types outside the mainstream.
I have a really hard time believing it's truly about respecting ones self at any size, when the trajectory is heading toward limited mobility and limited functionality.
They need to realize too that obesity (actual obesity, not just being curvy or pleasantly plump) is simply just not attractive to the vast majority of people, and no amount of accpetance movements and enlightenment and awareness raising is going to change that. It will likely be counter-productive.