One of my friends is a little plump, but completely at ease with himself and his size (he acknowledges he's bigger than average, but has no issues with the weight he's at). He was particularly fond of a certain comeback.
Rude Person: Why are you so fat?
Him: Everytime I went on a date with your mum she gave me a cookie.
In the case of the OP, don't ebgage was the best thing you could have done. I suppose at least someone spoke up to object...