We don't use adjectives like "fat" anymore.
I'm pretty sure the nurse knows she's fat-- pretending she's not doesn't help the situation. She should either embrace it (nothing wrong with being fat if that's cool with you) or work to change it by controlling diet and getting some exercise.
I'm short. Well, I'm 5'10" which is average but I'm pretty stocky so I think it makes me look shorter than I am. Almost everytime I've met someone they say "I thought you'd be taller." I tend to laugh and use the old Raymond Chandler response; "Well, I tried to be. Next time I'll come on stilts."
Bottom line-- just learn how to laugh and stop being offended by everything. This nannie world we've created is why kids are bringing Mom on job interviews now (and spoiler alert: they aren't getting the job).