A human body needs to take in about 2,000 calories a day to maintain itself. That’s the norm for most situations. In a harsh climate such as the Antarctic interior or the thin air of a high mountain chain, the caloric minimum may rise to 4,500 to 5,000 calories a day.
Without food, the body starts to burn its own fat for energy. When that’s depleted, the body cannibalizes its own tissues to stave off starvation. Long before the descent toward death, which begins after around three weeks without food, a person experiences “food stress.” Hunger preys on the mind, causing fixations and fantasies about food.
To the hungry person on the edge of survival, food fulfills not only a physical but also a psychological need. Ernest Shackleton noticed a marked improvement in his men’s emotional health when he increased rations from 9.5 ounces per day to a bit more, even though nothing else about their dire situation on the Antarctic ice had changed.
“Regardless of what it is, eat it,” Korean War prisoner of war Gene M. Lamm told John Leach in Survival Psychology. “If you miss one meal as a prisoner, it will take you weeks to regain your lost strength.”
BASIC FOOD ELEMENTS
Your body needs a variety of foods. They help the body maintain itself.
Carbohydrates are easily digested and supply rapid energy—particularly good for doing hard work under stress. They include grains, pasta, fruits, and vegetables. For a lightweight food full of energy, carry trail mix or hard candy.
Proteins build muscle and tissue. They come from meat, fish, and fowl. Don’t eat protein when dehydrated, as its digestion requires lots of water.
Fats burn slowly, giving energy over long periods. They include cheese, animal fat, butter, nuts, and eggs. Fatty foods provide warmth in cold climates.
Vitamins occur naturally in most foods, but you can also pack a vitamin-mineral supplement. Minerals also occur naturally in foods and in water.
FOODS YOU SHOULD CARRY ON A HIKE
Granola bars and small hard or chewable candies. Keep them in your survival kit for the bursts of energy they provide.
For day hikes: Trail mix, dried fruits, and other roughage. These contain fiber, nutrients, and carbohydrates. Snack on them as you go.
For longer trips: Plan for more elaborate meals that include a variety of foods. Consider the weather, distance traveled, available cooking gear and water, and dietary needs when choosing among canned, dried, freeze-dried, and preserved foods.
Canned foods are ready to eat and do not need fire or water, but add a lot of weight to a backpack.
Dried foods are much lighter but require plenty of water to reconstitute them—water that must be carried in or purified on-site. (Eating dried foods before they soak long enough will steal water from a person’s intestinal tract and possibly cause a dangerous blockage.) Freeze-dried foods retain their texture. These foods are lightweight and satisfying but must be soaked before cooking.
Small cans or bags of preserved fish or meat provide necessary protein with- out adding a lot of weight to a backpack, but digestion requires extra water.
Rice and beans, and other legumes are satisfying and rich in carbohydrates. They may require a little experimentation to cook properly on a camp stove.
Beverage powders have relatively little nutrition, yet drinks such as tea, cocoa, and coffee give warmth and comfort. Starting your day with a hot cup of coffee or tea can provide a psychological boost, suggesting your situation isn’t as bad as it seems. Powdered drink mixes also are handy if you are forced to collect water from pulverized vegetable matter or a brackish stream, or if you treat it with iodine. Purifying your water will kill germs but may not do anything for an unpleasant taste. Sprinkling a powdered flavoring on the water may help you keep it down. That’s an important consideration, as vomiting causes severe water loss.
End your day by eating protein or fat before going to bed. Digestion will help keep you warm throughout the night.
EDIBLE PLANTS AND ANIMALS
Foods found in the wild are either plants or animals. Both provide necessary nutrients in varying amounts. Though an ounce of meat has more nourishment than an ounce of vegetable matter, it usually is harder to obtain. Plants don’t run away as you try to collect them.
Plants are good sources of carbohydrates, which the body burns for energy. Nuts and seeds help balance the diet by providing proteins and fats, while plant foods containing sugars have calories for supplemental energy. Many plants can be kept from spoilage by drying through exposure to sunlight, fire, or air.
Young plant shoots are softer and more nourishing than old ones, as are young leaves. Leaves should not be boiled too long or they will lose their vitamins.
Obtaining meat requires skills to capture animals. An immediate need for protein can be satisfied by gathering easy-to-capture, abundant animals such as insects, crustaceans, snakes, and fish, whereas snares or weapons are needed to bring in larger animals. Beware the relatively high-energy expenditure of hunting.
Animal flesh should be cooked to kill microorganisms. However, in an emergency situation where fire for water purification is unavailable, the survivalist may choose to deal with an immediate hunger and thirst, and get treatment later for any resulting diseases.
The Army Survival Manual notes, “You can, with relatively few exceptions, eat anything that crawls, swims, walks, or flies.” A crucial step is overcoming the aversion to unusual foods.