Girl.... I once had a subordinate at work ask me if I was expecting. I was bloated and standing with my stomach out kind of holding my hand on my hip. She felt terrible when I said "nope, just fat..." I never held it against her in any way, but didn't feel good for sure.
My cat also act annoyed or sometimes visibly upset when I call him fat. I doubt that he understands what is fat or being called fat is a bad thing. Wonder why he is so sensitive about being called fat.