Should I Eat More at Altitude? What You Need to Know for High-Elevation Nutrition

Studies show that your body's energy expenditure can increase significantly at high altitudes, sometimes requiring thousands of extra calories per day. Given this increased metabolic demand, the question naturally arises: should I eat more at altitude? The answer is a definitive yes, though the reality is often complicated by a simultaneous decrease in appetite and other physical challenges.

Quick Summary

Your body burns more calories at altitude, but appetite is often suppressed by hypoxia. This guide explains how to increase energy intake with the right carbs, protein, and fat while staying properly hydrated to prevent weight loss and fuel performance.

Key Points

• Increase Calorie Intake: Your body burns more calories at altitude, so you must consume more energy despite potential appetite loss.

• Prioritize Carbohydrates: At least 60% of your calories should come from carbohydrates, as they are the body's most efficient fuel in low-oxygen environments.

• Stay Hydrated: You lose fluids faster through respiration and sweat. Drink 3-5 liters of fluid per day, ideally with electrolytes.

• Eat Often and Small: Combat suppressed appetite by grazing on small, easily digestible snacks every 30-45 minutes instead of large meals.

• Choose Easy-to-Digest Foods: Heavy, fatty, or spicy foods can cause digestive issues. Stick to simple carbs and lean proteins.

• Listen to Your Body: While the goal is to eat more, bringing palatable snacks you enjoy is key to ensuring you actually consume enough calories.

• Avoid Alcohol: Refrain from drinking alcohol, especially during the initial acclimatization period, as it worsens dehydration and AMS symptoms.

Why Your Body's Needs Change at High Altitude

When you ascend to higher elevations, the air pressure drops, meaning there is less oxygen available with every breath. Your body responds with several physiological adaptations to cope with this hypoxia. These changes directly impact your nutritional needs and challenge your ability to consume enough food.

Hypoxia and Increased Metabolic Rate

To compensate for the reduced oxygen, your body increases its breathing rate and heart rate, even at rest. This elevated baseline activity burns more calories. Additionally, your body temperature regulation, especially in colder mountain environments, requires more energy to maintain warmth, further increasing your overall energy expenditure. Researchers have found that daily energy expenditure for mountain climbers can reach 6,000 to 10,000 calories on hard days, far exceeding needs at sea level.

The Paradox: Increased Burn, Decreased Appetite

Despite the need for more energy, a common symptom of acute mountain sickness (AMS) is a significant loss of appetite, often accompanied by nausea. This is partly due to the body redirecting blood flow away from the digestive system to supply vital organs like the brain and heart with precious oxygen. This creates a dangerous paradox: your body requires more fuel, but your desire to eat is diminished. Ignoring this can lead to a negative energy balance, resulting in weight loss and compromised performance.

Essential High-Altitude Nutrition Strategies

Strategic fueling is key to counteracting the challenges of eating at altitude. The right mix of macronutrients is crucial for sustaining energy, aiding muscle recovery, and preventing a performance crash.

Prioritizing Carbohydrates

Carbohydrates are your body's preferred and most efficient energy source, especially in oxygen-deprived conditions. For mountain athletes, experts recommend that at least 60% of your daily intake come from carbohydrates. This is because your body uses them more readily for fuel and can optimize glycogen stores for sustained activity.

Recommended carbohydrate sources:

• Complex carbs: Oats, quinoa, brown rice, whole-grain bread, and sweet potatoes provide a steady, slow-release of energy.
• Simple carbs: Fruits, energy gels, and sports drinks offer quick bursts of energy, which can be vital for performance boosts during a climb.

Maintaining Protein and Fat Intake

While carbohydrates are the main fuel, protein and fat are still vital. Protein is essential for muscle repair and recovery, which is critical during multi-day expeditions. Portable protein options are particularly useful when fresh food access is limited.

Good protein and fat sources:

• Protein: Lean jerky, nuts, seeds, and protein bars are lightweight and packed with nutrients.
• Healthy Fats: Nuts, seeds, avocado (if accessible), and oils provide a high calorie-to-weight ratio, helping to meet your increased energy demands.

Hydration: Crucial at Any Elevation

Dehydration is a constant threat at high altitudes. The dry air, increased respiration rate, and colder temperatures lead to significant fluid loss that often goes unnoticed. Maintaining proper hydration is non-negotiable for mitigating altitude sickness and optimizing performance.

The Role of Electrolytes and Water

Fluid needs can increase to 3–5 liters or more per day at altitude. Simply drinking water may not be enough. Studies show that supplementing with electrolytes can be more effective than water alone for hydration at altitude. Electrolytes like sodium, potassium, and magnesium are lost through sweat and are vital for muscle and nerve function.

Hydration best practices:

• Carry a hydration pack or accessible water bottles to sip frequently.
• Drink even if you don't feel thirsty, as the sensation of thirst can be a delayed indicator.
• Use electrolyte tablets or sports drink powders to replenish minerals.
• Check your urine color; it should be light yellow.

Managing Appetite and Digestive Issues

Even with the right knowledge, consuming enough calories can be difficult. Here are strategies to combat altitude-related digestive issues and food aversion.

Tips for Eating When You Don't Feel Hungry

• Eat little and often: Instead of large meals, graze on small, frequent portions every 30–45 minutes.
• Choose easy-to-digest foods: Opt for simple carbohydrates and lean proteins that won't overload your digestive system. Soups, warm drinks, and porridges are often more appealing.
• Bring your favorites: Pack foods you genuinely enjoy. You are more likely to eat something you find palatable, even with a suppressed appetite.
• Stay warm: A thermos of hot tea with sugar can provide a morale and energy boost during a cold climb.

Foods to Avoid When First Arriving

• Heavy, fatty meals: These are difficult to digest and can contribute to nausea and sluggishness.
• Excessive alcohol: Can worsen dehydration and altitude sickness symptoms.
• Excessive caffeine: While a small amount can aid alertness, too much can be a diuretic and cause dehydration.

A Comparison of High-Altitude vs. Sea-Level Diet

Feature	Sea-Level Diet	High-Altitude Diet	Recommended Foods
Energy Needs	Lower, dependent on activity level.	Significantly higher due to increased metabolic rate, breathing, and thermoregulation.	High-carb, calorie-dense items like nuts, energy bars, and dried fruit.
Carbohydrate Priority	Balanced with protein and fat.	High priority; should make up at least 60% of total calories.	Complex carbs like oatmeal and quinoa; simple carbs like gels for quick energy.
Protein Intake	Standard daily recommendations.	Adequate intake necessary for muscle repair, though appetite can decrease protein consumption.	Lean, easy-to-digest sources like lean jerky or protein shakes.
Appetite	Generally stable.	Often suppressed due to hypoxia.	Focus on palatable, favorite snacks and smaller, more frequent meals.
Digestion	Normal function.	Can be compromised, leading to nausea or sluggishness.	Easily digestible foods like soups and porridges.
Hydration	Standard daily intake.	Increased needs due to dry air and increased respiration.	Plenty of water plus electrolytes.

Conclusion: Fueling Your High-Altitude Adventure

While the urge to eat may disappear at higher elevations, the necessity to do so dramatically increases. Ignoring your body's heightened energy demands is a primary reason for failed high-altitude expeditions and increased susceptibility to altitude sickness. By focusing on a high-carbohydrate diet, consuming food in small, regular intervals, and prioritizing hydration with electrolytes, you can overcome the challenges of altitude anorexia and give your body the fuel it needs to perform. Proper nutritional planning is just as important as physical training when preparing for a high-altitude trip. By being proactive and disciplined with your food and fluid intake, you can ensure a safer and more successful adventure. For more information on high-altitude health, you can consult with an expert at the Institute for Altitude Medicine.

Frequently Asked Questions

Why do I lose my appetite at high altitude?

Loss of appetite, or altitude anorexia, is a common symptom of acute mountain sickness (AMS) and is linked to the body redirecting blood flow and resources to more vital organs like the brain and heart to cope with less available oxygen.

How many extra calories do I need at altitude?

Energy needs vary widely based on activity level and altitude. Some studies show climbers can burn anywhere from 6,000 to 10,000 calories per day on strenuous days. It's safe to assume a significant increase over sea-level requirements.

Are carbohydrates the most important macronutrient at altitude?

Yes, carbohydrates are the most important at altitude. They are the body's preferred and most efficient energy source when oxygen levels are low, as they require less oxygen to metabolize than fats or proteins.

What are some easy-to-digest foods for high altitude?

Good options include simple carbohydrates and foods with high water content. Consider oatmeal, rice, soup, boiled potatoes, fruits, and snacks like energy gels, gummies, or dried fruit.

How important is hydration at high altitude?

Hydration is extremely important. The dry air and increased breathing rate lead to higher fluid loss. Increased hydration can help prevent or mitigate symptoms of altitude sickness.

Should I drink sports drinks with electrolytes or just water?

Drinking water is essential, but electrolyte-enhanced drinks or tablets are highly recommended, especially during prolonged exertion. They help replace minerals lost through sweat and can aid in better hydration.

Can high-altitude climbing lead to weight loss?

Yes, weight loss is common because many people fail to consume enough calories to meet their body's increased demands, particularly when their appetite is suppressed. Preventing significant weight loss is crucial for sustained performance and health.