He's fat. Tell him to get on a damn treadmill. One inch taller means spit. Bully's are pathetic jerkoff's trying to get negative attention because their mommies and daddies aren't there to listen to their crap, and neither should you be.
First off don't stoop down to his level. Don't fight him either because you'll both be in trouble if you get caught. And if you lose it will be another reason for him to bully you and if you win he'll have a reason to hate you. Have you tried talking to him about it? Also, bullying laws are being passed left and right so what he's doing is actually illegal so you have every right to report him. Also you can do it secretly and request to remain anonymous. Trust me. The people in charge know how to approach this type of subject without giving any hints about who might have told them. Also if you do retaliate he could use that against you if he ever gets in trouble and you'll get in trouble.
Stand up for yourself and call him out next time he says something offensive just be prepared to back it up....kinda strange you point out his preceived flaws so quickly though.