I searched the internet unsuccessfully to find suggestions of what to put into a 72-hour kit (something to sustain life). My ward just put new packs together so I thought I'd write out their suggestions and share them with all.
Breakfast- oatmeal and juice box
Lunch - ramen
Dinner - canned soup (our happens to be tomato)
Breakfast - granola bar
Lunch - applesauce and peanut butter crackers
Dinner - easy mac (flat packet, not the bowls)
Breakfast - oatmeal and hot chocolate
Lunch - easy mac
Dinner - ramen
cookies (like granny Bs)
salt water taffy
Put it all into a one-gallon ziploc -- change things out every six months (like at Christmas and 4th of July, or at General Conference).
Write the date packed and have at least 3 gallons of water.
I put the bag into a bigger backpack (or some people put it in their backpacker backpack to store... and remove it to use the backpack). I also have a deck of cards, a solar shower (like $5 at WalMart -- heats the water and makes it come out all shower-like), rain ponchos, couple Sterno cans, toothpaste, change of clothes, one of those tinfoil looking survival blankets, fire starters, TP, some soap, and a first aid kit.