Civilization Is Only 9 Meals Away From Anarchy!

What would happen if for any reason the just-in-time delivery system failed? What if you couldn't buy food at the grocery store? How many meals can you cook without resupplying your kitchen? How much food and how many days worth of food do you think that your friends and neighbors have in their homes? One day? Two? Three? What would people do if they started to get hungry?