Spending time outdoors can be hungry work, especially when doing something particular active like hiking, climbing, trail running or paddling and requires proper nutrition to ensure you have the energy and stamina to enjoy every moment. Understanding the basics of human nutrition is key to maximising your outdoor experiences. What are the essential aspects of nutrition for outdoor activities? What are calories, essential nutrients, and how should we prioritise our diet for optimal performance.

What are calories?

Calories are units of energy that our bodies need to function. When we consume food, our bodies convert the nutrients into energy, measured in calories. This energy fuels every activity, from basic metabolic processes to strenuous physical exertion during outdoor activities.

Why are calories important?

Calories are crucial because they provide the energy required for bodily functions and physical activities. Without adequate calorie intake, you may experience fatigue, reduced cognitive function, and impaired physical performance. For outdoor enthusiasts, maintaining proper energy levels is essential to tackle long hikes, climbs, or other strenuous activities.

Daily caloric needs

The number of calories you need per day depends on various factors, including age, gender, weight, height, and activity level. On average adult women need 1,800 to 2,400 calories per day and adult men need 2,200 to 3,000 calories per day.

Outdoor activities increase caloric needs significantly. A person engaging in a full day of hiking or other vigorous activities may require 500 to 1,000 extra calories to maintain energy levels and prevent fatigue.

Are all calories equal?

While a calorie is a measure of energy, not all calories are created equal in terms of nutritional value. The source of calories – whether from carbohydrates, proteins, or fats – affects how the body utilises them.

Carbohydrates are a primary, quick energy source, particularly important for high-intensity activities, crucial for immediate physical demands and are found in fruits, vegetables, grains, and legumes.

Proteins repair tissues, build muscles, and support immune function and are essential for muscle repair and growth. Found in meat, dairy, nuts, and beans.

Fats give us long-term energy storage, hormone production, and cell integrity, providing long-lasting energy and supporting cell function. Found in oils, nuts, seeds, and fatty fish.

Empty calories from sugary snacks or processed foods provide energy but lack essential nutrients, making them less beneficial for sustained energy and overall health.

Vitamins and Minerals are not calories but are essential for various bodily functions, including bone health, immune support, and energy metabolism. Key vitamins include A, C, D, E, and the B-complex group. Important minerals include calcium, iron, magnesium, and potassium.

How long can you go without food?

Many people make the common mistake of thinking that food is a survival priority in a survival situation. It isn’t. Whilst food is important the human body can survive for several weeks without food, depending on factors like body fat and overall health. 

Typically, a person can survive without food for about 30 to 40 days if they have adequate water intake. Immediate survival priorities are personal safety and air (breathing), then shelter, then water and only then food. We are unlikely to survive for longer than 3 minutes without air, 3 hours without shelter (hyper or hypothermia) and 3 days without water (depending on the environment and how quickly we are dehydrating).

However, energy levels, cognitive function, and physical performance decline significantly after a few days without food, highlighting the importance of regular nutrition during outdoor activities. We need to keep in mind that whilst we can survive for weeks without food we will not thrive! We need food in order to sustain ourselves for any period of time.

Prioritising Nutrition: Protein, carbohydrates, or vitamins and minerals?

For outdoor activities, prioritise your nutrition in the following order:

1. Carbohydrates – Ensure an immediate energy supply to fuel your activities.
2. Proteins – Support muscle repair and recovery, especially after strenuous activity.
3. Fats – Provide sustained energy for longer durations and support overall health.
4. Vitamins and minerals – Ensure a balanced intake to support various bodily functions and prevent deficiencies.

In a survival situation, it’s crucial to focus on foods that provide the most calories and essential nutrients with the least amount of effort. Here are some key considerations and food options to prioritise:

High-Calorie, Nutrient-Dense Foods

1. Nuts and Seeds

   – Calories per 100g: 500-700 kcal

   – Nutrient Benefits: High in healthy fats, protein, and essential vitamins and minerals (e.g., almonds, peanuts, sunflower seeds).

2. Dried Fruits

   – Calories per 100g: 200-300 kcal

   – Nutrient Benefits: Good source of carbohydrates, vitamins, and fiber (e.g., raisins, apricots, dates).

3. Jerky (Biltong)

   – Calories per 100g: 250-350 kcal

   – Nutrient Benefits: High in protein and can be stored for long periods (e.g., beef jerky, turkey jerky).

4. Energy Bars

   – Calories per 100g: 400-500 kcal

   – Nutrient Benefits: Balanced mix of carbohydrates, protein, and fats, along with added vitamins and minerals (choose bars designed for endurance and survival).

5. Peanut Butter

   – Calories per 100g: 588 kcal

   – Nutrient Benefits: High in fats and protein, easy to carry and store.

6. Chocolate

   – Calories per 100g: 500-600 kcal

   – Nutrient Benefits: High in fats and sugars for quick energy, along with some antioxidants (dark chocolate preferred).

Foraged Foods

1. Wild Edibles

   – Berries: Rich in carbohydrates and vitamins (e.g., blueberries, raspberries).

   – Nuts: High in fats and protein (e.g., acorns, walnuts).

   – Greens: Provide vitamins and minerals, though low in calories (e.g., dandelion greens, nettles).

2. Insects

   – Calories per 100g: 200-300 kcal

   – Nutrient Benefits: High in protein and fats (e.g., crickets, grasshoppers).

Priorities in Food Selection

1. Caloric Density

   – Focus on foods that provide the highest calories per gram to maximize energy intake without carrying too much weight.

2. Nutritional Balance

   – Aim for a mix of macronutrients: carbohydrates for quick energy, proteins for muscle maintenance and repair, and fats for long-term energy.

3. Storage and Preservation

   – Choose foods that have a long shelf life and are resistant to spoilage, such as dried or canned goods.

4. Ease of Preparation

   – Opt for foods that require minimal preparation or cooking, saving valuable time and resources.

Examples of Survival Food Kits

1. Emergency Ration Bars

   – These are specifically designed for survival situations, providing a balance of calories, fats, and sugars in a compact form.

2. Canned Fish and Meat

   – High in protein and fats, with long shelf life (e.g., canned tuna, sardines, chicken).

3. Dehydrated Meals

   – Lightweight and easy to prepare by adding water, providing a balanced meal (e.g., freeze-dried meals).

In a survival situation, focus on high-calorie, nutrient-dense foods that are easy to store and require minimal preparation. Nuts, seeds, dried fruits, jerky, energy bars, peanut butter, and chocolate are excellent choices. Additionally, foraging for wild edibles and insects can supplement your diet. Prioritising caloric density, nutritional balance, and ease of preparation will help ensure you maintain energy levels and improve your chances of survival.

Practical tips for outdoor nutrition

1. Stay hydrated – Always carry enough water and consider electrolyte solutions for longer activities.
2. Plan your meals – Prepare balanced meals and snacks that combine carbohydrates, proteins, and fats.
3. Pack lightweight, nutrient-dense foods – Choose trail mix, dried fruits, nuts, energy bars, and jerky (biltong).
4. Monitor your energy levels – Adjust your food intake based on your activity level and how you feel.

Understanding and implementing basic nutrition principles helps us equip ourselves to enjoy and excel in our outdoor adventures.

Remember, fuelling your body correctly is just as important as the gear you carry, your body is your number one ‘tool’!

References

1. Mayo Clinic (2023). ‘Nutrition and healthy eating: How many calories do you need?’ Available at: https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/calories/faq-20058429 (Accessed: 14 July 2024).
2. National Health Service (NHS) (2023). ‘Calories: How many calories should you eat a day?’ Available at: https://www.nhs.uk/live-well/healthy-weight/calories-how-many-calories-should-you-eat-a-day/ (Accessed: 14 July 2024).
3. Harvard T.H. Chan School of Public Health (2023). ‘The Nutrition Source: Carbohydrates.’ Available at: https://www.hsph.harvard.edu/nutritionsource/carbohydrates/ (Accessed: 14 July 2024).
4. Harvard T.H. Chan School of Public Health (2023). ‘The Nutrition Source: Protein.’ Available at: https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/ (Accessed: 14 July 2024).
5. Harvard T.H. Chan School of Public Health (2023). ‘The Nutrition Source: Fats.’ Available at: https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/ (Accessed: 14 July 2024).
6. World Health Organization (WHO) (2023). ‘Micronutrients.’ Available at: https://www.who.int/health-topics/micronutrients (Accessed: 14 July 2024).
7. Live Science (2023). ‘How long can you go without food?’ Available at: https://www.livescience.com/how-long-can-you-go-without-food (Accessed: 14 July 2024).

These references provide reliable and comprehensive information to support the key points discussed in this article.

Disclaimer

The information provided in this article is for educational and informational purposes only and is not intended as professional advice. While every effort has been made to ensure the accuracy and reliability of the information, the author and publisher make no representations or warranties of any kind, express or implied, about the completeness, accuracy, or suitability of the information contained in this blog for any purpose. 

Readers are advised to consult with a qualified healthcare professional or nutritionist for specific dietary needs and before making any significant changes to their diet or nutrition, especially in preparation for survival situations. The author and publisher shall not be held responsible for any adverse effects or consequences resulting from the use of any information, suggestions, or recommendations presented in this article.

In survival scenarios, conditions can vary widely and unpredictably. The strategies and food recommendations discussed are general guidelines and may not be suitable for every individual or situation. Always use personal judgment and consider your unique circumstances when applying any information from this article.