not as sophisticated as most, fairly inexpensive but not "ready to eat" composition for one day of my 72hour food pack:

packet instant oatmeal
(2)packet cocoa

tinned tunafish
ramen noodles or foil pack yellow rice
lift ring fruit cup
tub crystal lite
tea bags
boullion cubes
hard candy
peanut butter cracker snack

packed in and with spare 1 gal ziploc and 2'x2' square of aluminum foil