is there an insult which calls a man hugely fat. imagine having a person say that to you.
women are sensitive about weight, if there was an insult which hurts you based on something men are sensitive about like hair loss, let's say a guy said "bald like a bowling ball", i'm sure it would hurt
Im not going into the whole whether-its-right discussion, just focussing on the word as used in regular female conversations, i think it implies fat in a lazy/useless/indolent sloth kind of way. It could take on a variety of other meanings depending on the situation ofcourse. I like to think of it as the little black dress in your closet that you can accessorise however you please =D