My ex-husband used to claim that "gorda" was a term of endearment and indeed many parents call their children "gorda/o" and I have actually heard spouses use it as well, but all I could ever hear was "fatty" when he called me "gorda". [A little cross-cultural sensitivity no-no-e]. Another of his favorites, "vieja", meaning "old lady", was one I could tolerate a little better. I much prefered "querida" or "mi amor".