My bags (My own and ones I assembled for my sons) include a pot for boiling water, some camp tools, first aid kit, fire & signal kit (Including a flare gun and 6-8 flares), a survival gun with ammo, space blanket, fishing and trapping supplies, work gloves, a watch cap (You lose half your body heat through your head at night)m and three days or so worth of stable food items. Also two quart canteens each.
You can live without food for quite a while, but after 4-7 days without any carbs or fats your higher brain function starts checking out of the net and your metabolism shifts to a mode that can ultimately damage your liver and kidneys when your body has to start processing its own proteins to keep going.