She's vain and upset that despite her apparent fame she's still being put on the "yay fat chick role model" pedestal.  If she actually had a hot/enviable body, she wouldn't have to say anything about it and she'd be getting attention for being an attractive woman who is also comedically successful.  See: Tina Fey, Amy Poehler, etc. Edit: and Kristen Wiig! PS, size 6 my ass.