Susan,

Growing up in a German Jewish neighborhood, & then marrying a full-blooded
Italian, I've been faced with similar challenges--even before becoming an LC!
I find that the following strategies work (keep pulling them out till you find
out which one works for that particular situation!):

--Eagerly accept ONE "treat"--and pick the one LEAST attractive to you, then
nibble on it the whole time you're there.

--NEVER FINISH WHAT'S IN FRONT OF YOU!  Then they'd have to offer you more.

--In refusing, you can say "I couldn't POSSIBLY eat another bite", and you
have that "last bite" in front of you to prove you can't finish it!  (After 17
years of marriage, my husband STILL cannot finish everything on his
plate--always leaves that one bite!)

--Blame it on your doctor:  "My doctor has warned me that I'll end up in the
hospital if I keep eating such & such:  my metabolism can't handle it".  This
makes it look like your body's at fault, not their food.  And they usually are
in awe of doctors, so "if the dr. told you not to..."

--Always ask for a glass of water INSTEAD of whatever they're offering you.
They need to get you SOMETHING, so a glass of water, a piece of fruit, etc.
fulfills their social obligation, and yours.

Hope this helps.  I actually got thru 10 years of marriage before old Mrs.
Serena, who would always look me up and down & say, "Do you feel OK?  You look
so skinny!" one Christmas smiled, pinched my cheek, & said, "Carol, you look
good!"  I started my first major diet that day....

Carol, in sunny St. Louis (60 degrees, & they're STILL predicting a white
Christmas!)