Artists like John Waters & Jennifer Reeder have made careers riffing on the stigma of the "unfit."
That said, one can't quite embrace all degrees of obesity as one may embrace dark skin & nappy hair, small hips & almond eyes, and so on (which have been also stigmatized as "ugly" by racists), for too much fat can have dire health consequences. In many tribes, for instance, morbidity & mortality from diabetes are high, due to poor diets & environments that settler colonialism has forced upon them. In short, one can't reject physical fitness altogether as just another instance of the "tyranny of normalization."
Yoshie