Are Fat Men More Socially Acceptable Than Fat Women?

I'm starting to feel like it is socially acceptable for a man to be fat, but not a woman.  You hear comments like, "he's a big boy" about fat men.  But you hear something different about fat women.  You hear things like, "she really let herself go", or "she'd be really pretty if she lost some weight".  Are we okay with men being fat, but have something against a woman being fat?  After all, women are supposed to be beautiful, right?  And being fat isn't seen as being beautiful.  I wonder if there are gender differences in what is acceptable in terms of being overweight or obese.  Have you had any experiences with this?