We all know that fashion does not realistically depict women, in that most women weigh over 80 pounds. It's a good thing that books do not fall prey to this slimmed down version of reality. Oh, wait, never mind.
I think where Jezebel is particularly on the money is that the covers highlighted (at the link above) are not supposed to represent just any women; they're meant to represent large ladies as protagonists. Like the Bloomsbury cover whitewashing debacle(s), this shows that publishers think that no one will pick up a title with a big girl on the front (even if the title is "Big Boned").
One day soon, reader types, we will not be treated like idiots. At least, that's what I keep telling myself.