There seems to be a stereotype in the gender community that one has to be petite or have feminine features to be credible. Significant body fat, it seems, tends to androgynize. It softens facial features. Also, men are broad in shoulders, heavy in waist, and narrow in the hips.
Women are narrow in shoulders, flatter in waist, and wider in the hips.
But heavy women are round everywhere, and heavy crossdressers are round everywhere. Heavy women also have an advantage in that they aren't necessarily scrutinized as much by passersby. Our society devalues obesity and idolizes anorexia, and people are more forgiving of a chubby woman's imperfections. In fact, they give her much less of a glance than they give to other women. As it happens, older age also tends to androgynize people.