We don't have to accommodate all the fat people. Throw slightly bigger chairs around two of the tables and shrink the booths. Give each table a noise monitor so that, if they make too much noise either shredding food or assaulting our eardrums with their obnoxious vocal cords, the monitor beeps really loudly and everyone can glare at them. Three beeps and they get kicked out. Bonus points if everyone has something to throw at them on their way out.