When venturing into the backcountry, whether for a day or an extended trip, food and water are part of your safety plan. As modern humans living in a culture of relative abundance, it is easy to forget that inadequate food and dehydration are not merely a matter of discomfort but can actually be dangerous. 

Wilderness nutrition recommendation number one: bring plenty of clean water to start, and some type of water disinfectant or purification system to replenish your supply throughout the day. Boiling water works well at camp but is not practical otherwise. Chlorine-based tablets are an inexpensive, lightweight option to keep in the bottom of your pack for emergencies if you don’t have or prefer not to bring a water filtration system.

Most adults will need anywhere from 3-5 liters of water for a day in the backcountry, depending on the duration of trip, level of intensity, environmental temperature, and level of fitness. High altitude, extremes of hot and cold temps, excessive sweating (sometimes difficult to gauge in windy and/or dry climates where sweat quickly evaporates), low level of physical fitness, and heavy packs increase fluid needs. It is best to sip small amounts throughout the day since you can only absorb roughly 1 ounce per minute. 

You may be familiar with the annoyance of a dehydration headache. As this condition progresses due to inadequate fluid, fatigue and other factors that lead to poor decision making can create a dangerous situation.

Symptoms of Dehydration*:
Mental confusion
Increased heart rate
Decreased urine output
Dark-colored urine output

The second most important wilderness nutrition goal: bring enough (or extra) food. Calories = energy. For safety reasons I always bring more food than I think I will need, just in case. Extra can be as simple as an energy-dense (high calorie) bar or extra trail mix at the bottom of my pack.

Unfortunately, the way we are encouraged to eat in the front country may not be what works best during a day of demanding physical activity in the backcountry. Heeding nutrition messages to “eat less” and avoid fat, sugar/carbohydrates, and salt can lead to a shortage of energy and key nutrients when you venture into the backcountry. Also, when you are working hard your core temperature rises and appetite decreases so you may need to eat in the absence of hunger, a counterintuitive situation for most of us.

Five hours of general hiking (not including uphill or a heavy pack) burns roughly 1,700 calories for a 130-pound adult and 2,400 calories if you weigh 180-pounds*. Shivering in cold, wet and/or windy conditions requires additional fuel. 

Foods we may eat sparingly at home to avoid excessive calories such as nuts, peanut butter, and dried fruit are great choices for the backcountry when compact, lightweight sources of energy are your friend. Salty foods such as nuts and jerky provide sodium to replace what you lose in sweat throughout the day. 

Carbohydrate foods provide a mix of quick- and slow-burning fuel for brain and muscles. We store roughly 1,400-1,800 calories of glycogen (storage form of carbs), in our liver to fuel our brains and in muscles to fuel activity. This is enough for about 1-3 hours of continuous moderate-to-high intensity exercise depending upon a variety of factors.

Any time you are breathing hard you are burning mostly carbs of some sort. When you are adjusting to high altitude, suffering from a lack of fitness, increasing your pace, climbing uphill, or moving in a hot or cold environment, your fuel mix will lean heavily toward carbohydrate sources. Some amount of fat and protein provide fuel during a long day of exercise, but adequate carb intake makes more protein available for a variety of important tasks. Many vital functions require amino acids from protein such as building and repairing muscles, making the variety of cells needed for blood, brain chemicals, immune system, digestion, and more.

While you have probably experienced grumpy moods or perhaps even headaches that accompany hunger, inadequate food (especially carbohydrates) can lead to other symptoms of low blood sugar that pose safety risks. These include: dizziness, confusion, disorientation, weakness, fatigue, and anxiety. Even irritability and a pounding headache can lead to poor decision making in the backcountry.

Factors that Affect Food Choices in the Backcountry*
Food preferences
Weight, perishability, taste, and texture of foods
Pack space
Length of trip (or ration period)
Availability of water and fuel for food preparation
Environmental conditions (heat, humidity, cold, altitude, etc.)
Individual and group experience with cooking and food preparation
Special dietary needs (food allergies, medical conditions, etc.)
Beliefs about food and nutrition
With the variety of factors listed above that influence food you bring into the backcountry, I will add that keeping it simple is often the best strategy. After decades of backcountry experiences I still love a good PBJ sandwich (on whole grain bread), trail mixes with a fun variety of nuts, seeds, dried fruit and dark chocolate chips, whole wheat fig bars, and something salty like jerky or crackers and cheese. If I’m only out for the day I like to bring something fresh like grapes, an apple or orange, a small avocado or carrots—unless pack weight or space is an issue such as a rock climbing trip.

Enjoy your wilderness adventures and remember that all that fancy gear and clothing is great, but the basics of adequate food and water, the bane of many a backcountry expedition, remains! As my friend and backcountry food mentor at NOLS Claudia Pearson and I like to say: gear is good but food is better.

*Source: Howley Ryan, M. (2008). NOLS Backcountry Nutrition: Eating Beyond the Basics. Mechanicsburg, PA: Stackpole Books. 

Mary Ryan, MS, RDN, CEDRD, LD

Mary Ryan, MS, RDN, CEDRD, LD

About the Author

Mary Ryan, MS, RDN, CEDRD, LD
Mary Ryan is a Master’s level Registered Dietitian with a special focus in behavioral nutrition as a Certified Eating Disorder specialist, licensed in Wyoming and Idaho. Beyond Broccoli Nutrition Counseling & Education is her private practice based in Jackson Hole, Wyoming. Mary is the author of National Outdoor Leadership School (NOLS) Backcountry Nutrition: Eating Beyond the Basics (2008), a contributor to the Wilderness Medical Society’s Trail Mix column, and spends her free time outdoors as much as possible!