The Extreme Caloric Demands of Thru-Hiking
Thru-hiking, an endurance sport involving hundreds or thousands of miles of walking, pushes the body to its physical limits. For the duration of their journey, hikers transition from a standard diet to one fueled by constant, high-octane calories. While a typical person's daily caloric requirement is around 2,000-3,000 calories, a thru-hiker can burn 500-700 calories per hour while carrying a heavy pack. This translates to a daily burn rate that can easily exceed 5,000 calories, and in some cases, can push towards 10,000 calories for hikers pushing high mileage.
The most significant variables influencing a hiker's specific needs are their body weight, the terrain's difficulty, and the weight of their pack. A heavier hiker will burn more calories than a lighter one, and a route filled with steep climbs will demand more energy than flat ground. As a result, most thru-hikers learn to constantly snack and rely on calorie-dense foods to keep their energy levels high, often eating until they are uncomfortably full in towns to offset the constant caloric deficit they operate under.
The 'Hiker Hunger' and Caloric Deficit
Even with a focused eating strategy, many thru-hikers find it nearly impossible to consume enough calories to match their daily expenditure, particularly in the initial weeks of a hike. This creates a sustained caloric deficit, which is why significant weight loss is a common experience, especially at the beginning of a trek. Eventually, a phenomenon known as 'hiker hunger' sets in, an insatiable craving for food that drives hikers to consume massive quantities whenever they have the opportunity. This is the body's natural response to weeks of being under-fueled, and it’s a clear sign that a hiker's metabolism is in overdrive. While it might seem unhealthy, this deficit is often unavoidable given the logistical challenges of carrying enough lightweight, high-calorie food.
Strategic Food Planning: Calorie Density is King
To maximize caloric intake while minimizing pack weight, thru-hikers prioritize calorie-dense foods. This means every ounce of food must deliver maximum energy. Fats are particularly valuable for this, containing 9 calories per gram compared to carbohydrates and protein, which have only 4 calories per gram. This is why olive oil is a beloved staple, with some hikers adding it to nearly every meal for an easy calorie boost.
Strategic food planning also involves considering the type of trail. Hikers on a route with frequent resupply points can afford more variety, including heavier but more nutritious items. Those on longer stretches between towns, however, must focus exclusively on ultralight, calorie-dense options, which are often heavily processed. The rise of dehydrated and freeze-dried backpacking meals has also provided hikers with a more convenient, if expensive, option for warm meals.
A Typical Thru-Hiker's Daily Menu
Here is an example of what a 5,000-calorie day might look like for a seasoned thru-hiker, combining calorie-dense and lightweight options:
- Breakfast: Instant oatmeal with added nut butter packets, dried fruit, and coconut milk powder.
- Mid-Morning Snack: A large handful of macadamia nuts or almonds.
- Lunch: A tortilla wrap with instant hummus powder, summer sausage, and olive oil.
- Afternoon Snack: A mix of trail mix with M&Ms, cheese, and jerky.
- Pre-Dinner Appetizer: Fritos or a similar salty, high-fat chip snack.
- Dinner: A pouch of freeze-dried meal or instant mashed potatoes mixed with instant beans and added powdered cheese and olive oil.
- Dessert: A chocolate bar or gummy candies for a quick sugar boost.
Calorie Breakdown by Food Type
This table illustrates the calorie density of common thru-hiking foods, highlighting why certain items are essential for maximizing energy per ounce.
| Food Item | Calories per Ounce | Macronutrient Focus | Weight vs. Calories | Example Use Case |
|---|---|---|---|---|
| Olive Oil | 248+ | Fat | Extremely High Calorie Density, Very Light | Adds calories to any meal |
| Nut Butters | 168-190 | Fat, Protein | High Calorie Density, Very Light | Spreads on tortillas, adds to oatmeal |
| Trail Mix | 125-150 | Carbs, Fat, Protein | Moderate-High Calorie Density | All-day snacking |
| Hard Cheese | ~115 | Protein, Fat | Moderate Calorie Density | Meal ingredient or standalone snack |
| Freeze-Dried Meal | 100-120 | Balanced | Moderate Calorie Density | Hot dinner |
| Oatmeal | 80-100 | Carbs | Moderate-Low Calorie Density | Breakfast base |
| Jerky | 80-100 | Protein | Moderate Calorie Density | Salty protein snack |
The Challenge of Micronutrient Intake
With a heavy reliance on processed, calorie-dense foods, thru-hikers often fall short on essential micronutrients like vitamins and minerals. While the initial weeks may not show significant effects, a prolonged lack of fresh fruits, vegetables, and other whole foods can lead to deficiencies. This is often why hikers crave fresh salads or fruit upon reaching a town. Some experienced hikers and dietitians recommend carrying a multivitamin or supplementing with fortified drink mixes to mitigate this risk, though getting all necessary nutrients from a dehydrated diet is difficult.
Conclusion
Thru-hikers must consume a staggering number of calories daily, often ranging from 4,000 to well over 6,000, to fuel their demanding physical activity. The specific number depends on individual factors like body size, pack weight, and trail difficulty. Due to the sheer energy expenditure and logistical constraints of carrying food, operating in a caloric deficit is common, leading to the well-known phenomenon of 'hiker hunger'. Successful long-distance hikers become masters of maximizing calorie density by packing foods rich in fat and carbohydrates, though they must also be mindful of supplementing their diet with micronutrients to maintain health and performance. Ultimately, a thru-hiker's diet is less about gourmet meals and more about strategic, continuous refueling to keep moving down the trail.
For more information on balancing nutrition for endurance sports, visit the Academy of Nutrition and Dietetics at eatright.org.
Factors Influencing Calorie Needs
- Body Weight: A heavier hiker burns more calories covering the same distance than a lighter hiker.
- Pack Weight: A heavier pack increases the energy required to hike, boosting overall calorie expenditure.
- Terrain: Steep ascents and difficult terrain dramatically increase calorie burn compared to flat ground.
- Metabolism: Individual metabolic rates, age, and fitness level play a significant role in how the body processes and utilizes energy.
- Mileage: The number of miles a hiker covers per day is a primary factor, with higher mileage requiring substantially more calories.
- Climate: Hiking in extreme hot or cold weather can increase caloric demands as the body works harder to regulate temperature.
Thru-Hiking Food Strategy
- Prioritize Calorie Density: Focus on foods with high calories per ounce to reduce pack weight, such as olive oil, nuts, and chocolate.
- Eat Continuously: Instead of three large meals, hikers should graze throughout the day with frequent, small snacks to maintain steady energy levels and avoid 'bonking'.
- Don't Fear Fats: A high-fat diet is effective for thru-hiking as fats provide sustained, slow-burning fuel. Items like nut butters and cheese are essential.
- Replenish Glycogen: Carbohydrates are vital for immediate energy and restoring muscle glycogen after a long day. Instant grains and simple sugars are common choices.
- Replenish in Town: Hikers should take advantage of resupply stops to eat large, elaborate meals and consume fresh produce to replenish micronutrients often missed on the trail.
