Is it harassment if a sheriff says you are to big to be in a back seat of a gmc jimmy and say you look like you are about to explode like a pimple I'm a big guy and I take that as he was calling me fat and can I sue

You seem to be asking about defamation (slander, particularly), not "harassment". Harassment, if actionable, I guess would be repeatedly bothering you for no good reason. Truth is a defense to a suit for defamation.

If you are a "big guy", you probably are fat. You cannot sue for what constitutes nothing more than a case of hurt feelings.

So, no.

Anyone can sue over anything. The real question is can you win. I see nothing close to grounds for winning a suit.