Well you can get yourself along to a super market where you normally come across something called "Shishoku Corner" ] - its usually a table set up with samples of food for you to try out. Some of the Shishoku Corners are filled with everything from freshly cooked sausages (like the ones in this picture) to sushi, sashimi, Gyoza (fried dumplings) etc.
Some folks like Crayon Shinchan can walk in and out on a full stomach - especially at the
Daiei in Himonya.