Climbers in the mess tent eating popcorn on Kilimanjaro

The best foods and drinks for acclimatising to high altitude

Nov 24, 2023
Reading time: 8 minutes

Trekkers, please take note: high altitude places strain on your digestive system. You can avoid unpleasant issues like constipation and diarrhoea by eating certain foods and avoiding others. Read on to learn who's a friend and who's a foe at elevation!

It's important to eat thoughtfully when trekking at high altitude. Not only do you need plenty of energy to manage all that hiking, but you also want to eat and drink the right things to help your digestion cope with the changes in atmospheric pressure and oxygen levels.

With this in mind, let's look at specific foods (and drinks) to befriend at high altitude. We then look at those to dump. Because stomach issues are a surefire way to ruin a big adventure!

The best foods and drinks for acclimatising

Here are some foods and drinks that will be kind to your digestion and actually aid you in acclimatising as fast as possible ...

1. Water

Water helps to mitigate the negative effects of high altitude, including digestive discomfort. So please make drinking lots of clean water your top priority when at high altitude.

If you remember only one thing from this blog post, please let it be to drink plenty of water when at high altitude!

Note that you want to drink clean or purified but not distilled water at high altitude. Distilled water has been stripped of important minerals like magnesium and calcium, and you need these, especially when doing intense physical activity.

Woman in bush hat drinking water on trek

Water is key to acclimatising well

If you struggle to drink plain water, by all means, add some flavour through the likes of electrolyte sachets. In fact, electrolyte sachets are important for everyone doing a really hard trek to ensure the body doesn't run out of certain important minerals like sodium, zinc and chromium.

You could also try to eat water-dense fruits like watermelon and drink herbal teas.

2. Complex carbs like oats

Complex carbohydrates like oats, quinoa, sweet potatoes, peas, lentils, beans and brown rice provide a steady release of energy that can be helpful when adjusting to lower oxygen levels. These won't place strain on your gut and will also fuel for long days of hiking.

Salad of kale, sweet potatoes and avocado

Sweet potato is an excellent complex carb to enjoy at high altitude

3. Iron-rich foods like spinach

Adequate iron is necessary for your blood to transport oxygen throughout your body. And improved oxygenation is key to altitude acclimatisation.

You get nice doses of iron in foods like lean meats, poultry, fish, beans, lentils and dark leafy greens. What's great is that these foods also provide other nutrients that are important at high altitude, as you'll see if you read on.

4. High-antioxidant foods like berries

Antioxidants help to combat oxidative stress associated with high altitude. You can find lots of antioxidants in fruits like berries, oranges and mandarins as well as in leafy greens.

Hot oats and berries in a bowl with a spoon

Oats and berries are a good breakfast option when acclimatising on a trek

5. Potassium-rich foods like bananas

Potassium helps to maintain proper muscle and nerve function. This is especially important when acclimatising to ever-higher altitudes on a trek.

Three particularly excellent sources of potassium are bananas, potatoes and spinach. If you're unsure that you're going to be able to get enough potassium in your diet during your trip, you might want to consider packing a supplement.

Meals on Kilimanjaro

Spinach is a winner at altitude as it provides iron, potassium and antioxidants

6. Lean proteins like lentils

Protein is important for many things, including muscle repair and the synthesis of haemoglobin (the protein in red blood cells that carries oxygen from the lungs to the rest of the body). So it's important to get enough protein on a high-altitude trek.

That said, you want to opt for lean protein as excessive fat can slow down the acclimatisation process. (More on that later.)

Lean animal-based protein options include skinless chicken or turkey, white-fleshed fish like cod and salmon, egg whites, cottage cheese and Greek yoghurt.

Vegans could major in the likes of lentils, peas, tofu and beans. And if you're unsure about the protein options you'll encounter on your trek, perhaps consider packing a healthy protein shake or similar.

7. Garlic and ginger

Some people believe that garlic can help to improve blood circulation and thus potentially aid in acclimatisation. Meanwhile, ginger is known for its anti-nausea properties, and nausea is a common symptom of altitude sickness. So eat ginger and garlic on a high-altitude trek if you can!

8. Coriander (cilantro) and cocoa

Some studies suggest that coriander and cocoa help to increase the body's oxygen-carrying capacity. Whether true or not, hot cocoa after a cold day of trekking is certainly going to be beneficial, even if it's just for the soul!

Carrot and coriander soup in a white bowl

Coriander (cilantro) potentially helps your body to acclimatise

9. Acetazolamide

Okay, so this isn't a food, but you do pop it into your mouth!

Acetazolamide is a medication often prescribed by doctors to help clients acclimatise better. It's often referred to by the popular brand name Diamox.

Finally, it's important to listen to your own body's cues when at high altitude. Every human body is different and so reactions to a new altitude can and do vary. If you have a craving for a second banana, for instance, then eat that banana, as it's probably your body telling you that you need a potassium fix.

The worst foods and drinks when acclimatising

Certain foods and drinks will hamper your body's acclimatisation process, and so should be avoided at high altitude ...

1. Very salty foods

Excessive salt can lead to dehydration, and dehydration increases your risk of developing altitude sickness. So please avoid foods high in sodium like fast foods, canned soups and any chips (crisps), crackers and pretzels laden with seasoning.

That said, you do absolutely need some sodium in your system or your body will shut down. So please don't overcorrect and eliminate all salt!

2. (Excessive) caffeine

Caffeine isn't your friend at high altitude as it can lead to dehydration. So we encourage you to avoid caffeinated liquids like coke, coffee and energy drinks at high altitude, especially during your initial acclimatisation.

Nepal EBC trek, group pic hot drinks outdoors restaurant

Consider hot chocolate, chai, decaf or herbal tea when wanting a hot drink

If you're a caffeine addict, consider weaning yourself off of it before the trek. If you feel this isn't doable, then at least try to minimise your caffeine consumption. And it's better to do any weaning before the trek, as while caffeine isn't helpful at altitude, you also don't want to have withdrawal symptoms on your trek!

Furthermore, ensure you follow up every caffeinated drink with at least an equal amount of water.

Note that dark-yellow urine is a sure sign that you're dehydrated.

3. Heavy, fatty meals

Large, heavy meals can make you feel sluggish and can contribute to altitude-related nausea or digestive discomfort because they're harder to digest.

When on a high-altitude trek, opt for smaller, more frequent and easily digestible meals. Leave fatty burgers, thick milkshakes and the like for after the trek!

Speaking of milkshakes ...

4. Lots of dairy

Dairy is a common culprit for digestive discomfort, especially at high altitude. So some folks who usually eat dairy might find that limiting their intake helps with their digestion at high altitude. Or at least be cautious with dairy at the start of your trek, and then see how you feel.

Male trekker seated on rock pouring drink out of flask

It's better to opt for non-dairy hot drinks if possible

5. Highly processed foods

Highly processed foods aren't good for your digestion at the best times, so it's unsurprising that they're hugely unhelpful at high altitude!

Highly processed foods are usually high in salt and unhealthy fats, while also lacking the nutrients your body needs for good acclimatisation. You want to be in top form when doing a high-altitude trek, so we recommend steering clear of highly processed foods like burgers, sausages, lunch meats, instant noodles, pastries, cakes and certain protein and energy bars.

6. Spicy foods

Some people find that spicy foods exacerbate any altitude-related digestive issues, so it might be best to avoid them, especially if you're prone to digestive woes. We're looking at you, peppers and chillies. ๐ŸŒถ

spicy veal with potatoes in gravy and rice - Peruvian dish

Heavily spiced foods aren't great for your tummy when you're acclimatising

7. Sugary foods

Food and drinks high in sugar like sodas, fruit juices, chocolate (candy), desserts and sweets can lead to energy spikes and crashes. You want to try to sustain even blood sugar levels when acclimatising.

When faced with a sugar craving, try instead to eat whole fresh fruits or snacks sweetened with ingredients like stevia, maple syrup or xylitol as these all have low glycaemic indexes.

Please note: it's important to eat at regular intervals on a high-altitude trek and not skip meals as low blood sugar can worsen the symptoms of altitude sickness.

Finally, please give your body as much time as possible to rest when adjusting to high altitude. Not only does rest speed up the acclimatisation process, but it will also give your body time to focus on its digestion.