No.  Fat is an insult the same way ignorant is. Fat is a negative character trait.  It indicates a lack of human will power.  Being fat is bad.  Being fat is shameful. Being fat, like being ignorant, is a choice that one should feel shame at choosing.  It's worse than ignorant, its like being a criminal.  Everyone starts ignorant.  Many people stop being ignorant. No one starts as a fat or a criminal. So yes, it is an insult, even though it's true.  Fats have chosen to be sub-human.  And they are bad, shameful, people for doing so.