I've seen bigger girls without back problems. That, and this is a fictional character in a fictional setting. I don't think back problems are an issue.
Probably should be more of a worried about the fact her body can't hold up that kind of fat. Especially since her arms are that skinny but her legs and chest and everything else is like 3x bigger then her..
There are real women that are built like that, assuming you're trying to imply the opposite
Usually they are fairly petite apart from their body fat
Proportion wise there are characters on this site that are way worse. Asanagi's conception of the female form isn't that bad at all (well, at least in this picture), albeit pretty specific.
