In a wilderness survival situation, it is possible to live for extended periods of time on little or no food. Research shows that a healthy individual can survive on 500 calories a day with no side effects and with plenty of water and a comfortable resting place can live approximately three weeks without food. During cold weather or periods of heightened activity more food is required to maintain a normal body temperature.
Water is much more important. Two to three cups of water are required each day to stay healthy. It is wise to conserve the water in your body by reducing activities that may promote water loss.
Finding water during the summer months is quite easy. Running water such as springs or streams in isolated areas is generally safe for consumption but be aware that water in stagnant areas such as sloughs and ponds may carry disease and should either be boiled for a minimum of three minutes, or iodine (nine drops per quart) or halazone tablets added.
It is wise to carry a water purification pump with you. This allows the hiker to make use of stagnant water in any situation and it is not necessary to carry water with you. In areas where no surface water is available, dig into damp soil and allow this muddy water to settle and become clear. Water may also be found on the dew of plants, by collecting rainwater or in fish juices.
During the winter months it is wise to look for water under ice. Melting ice as opposed to snow is more fuel efficient. Remember that hard-packed snow will yield more water than light, fluffy snow. Do not eat snow as it tends to dehydrate the body.
Finding food in the wilderness may prove slightly more difficult but by no means impossible. Try and sustain with natural foods before using your emergency survival kit rations.
If water is not readily available try to limit your food consumption to carbohydrates, as proteins use more water to digest. Keep in mind that all fur-bearing animals and grass seeds are edible and that there is more food value in the roots of plants than the greens.
Extra care should be taken when consuming seafood. Try to avoid mussels during the summer months as they contain certain toxins which are not present during the winter. Sea urchins, a prickly purple or green sea creature, may be consumed by breaking them open and eating the red or yellow eggs inside. Steam snails, clams and limpets. Frogs, snakes, lizards and birds are also edible. Remove the head, entrails and skin before adding them to the pot.