We can totally understand not wanting to die.
Not dying is usually the reason most people do anything they do. (Except maybe BASE jumpers and vampire hunters. LOLz!)
He believes that they'll have trouble getting the needle into his arm and that he might break the gurney he's strapped to during his lethal injection.
We're pretty sure they're not going to postpone it because of his weight.
Check out the video (above) to hear a murderer try to use his weight to get out of dying.