I used the 'f' (fat) word when talking to my sister who is overweight a couple of years ago. I don't usually use that word - it just slipped out - and it wasn't in relation to her but she took me down a couple of notches over it. I know it is really her issue because she is so sensitive over the weight she had gained but I suppose it doesn't hurt to be cautious with describing or labeling people in any way. That said, you can do your best and still step on someone's toes occasionally. Like me, you meant no harm.
Maybe today's PC is what yesterday's generation called 'good manners'?