Was Bart Allen hungry? Was that a trick question? Bart was always hungry. His metabolism processed foods at super speed, converting everything he ate into energy-- of which Bart had (and needed) lots of. Of course he was hungry!
"Oh yeah! That sounds good. Um I think we have stuff at the house to make them or there might be a place nearby?" Actually, he knew there was a diner not far-- surely they had grilled cheese on the menu. Though he didn't know if they had wifi.