Call me crazy, but I think that Orange Juice could represent Mrs. Potato Head (the character) as a child. Think about it, Mrs. Potato Head seemed excited by the idea of surgery even before her husband suggested it. So maybe as a child, Mrs. Potato Head was bulimic which may have influenced her future decision.
And no, I don't believe the Fleur is Mrs. Potato Head. Orange Juice could technically be about any bulimic person, not just Fleur.
Yes, that's the theory: I think Orange Juice could be a prequel to Mrs. Potato Head.