Polar expedition nutrition: what to eat in extreme cold

Written by James Frost, founder of Flaming Phoenix and the maker of Phoenix Bars. Updated November 2026.

Quick answer: Plan on 5,000 to 7,000 calories a day on a polar expedition, from food that averages 4.5 to 5 calories per gram, so a 6,000-calorie day weighs about 1.2 to 1.3kg per person. Pick foods with very little water in them, because anything wet freezes hard and stops being something you can eat on a five-minute break.

Even at that intake most people lose weight. Hauling a pulk for eight to ten hours a day at -30°C burns more than most people can eat, appetite tends to fall as the days go on, and every extra kilo of food is a kilo you drag. This guide covers how many calories to plan for, which foods still work at -30°C, how a polar day is fed and how to work out the food weight for a whole trip, for anything between a week-long Last Degree ski and two months on the way to the South Pole.

How many calories do you burn on a polar expedition?

In temperate conditions, a moderately active adult requires roughly 2,000 to 2,500 calories per day. On a polar expedition (hauling a loaded pulk across ice, sastrugi or snow for eight to twelve hours a day in temperatures that can drop below -40°C), calorie expenditure rises sharply, often to between 5,000 and 7,000 calories per day, and sometimes far higher.

The best measurements come from Ranulph Fiennes and Mike Stroud's 1992 to 1993 crossing of Antarctica: 2,300km in about 95 days with no outside help. They ate about 5,090 calories a day, Stroud's doubly labelled water measurements put what they burned at around 7,000 a day on average and more than 11,000 a day at the peak, while hauling up onto the polar plateau, and both men still lost more than 20kg. Few people will haul for that long, but the gap between what you burn and what you can eat is the same problem on a three-week Greenland crossing.

This increase comes from three sources. The first is the sheer physical effort of hauling a pulk weighing 70 to 100kg or more across uneven terrain. The second is thermogenesis: the calories your body burns to hold its core temperature when the cold is more than your clothing and shelter can fully keep out. The third is the metabolic cost of operating in a hostile environment over many consecutive days, where sleep quality is often poor and recovery is limited.

The practical consequence is that most polar travellers lose weight during their expedition regardless of how much they eat. The goal of a polar nutrition plan is not to eliminate this deficit entirely, which would mean carrying an impractical amount of food, but to minimise it enough that you retain the strength, cognitive function, and morale to complete the journey safely.

Why is calorie density the key number for polar food?

On a polar expedition, food weight is one of the largest components of total expedition weight. A 60-day ski to the South Pole needs 60 to 90kg of food per person, depending on how calorie-dense that food is. Every unnecessary gram adds drag to your pulk and slows your daily progress: a day's 6,000 calories weighs about 1.3kg at 4.5 calories per gram, against 2kg at 3.0 calories per gram.

So calorie density (the number of calories per gram of food) is the first number to check in polar food planning. For a detailed explanation of calorie density and how it applies across different situations, see our guide to calorie-dense foods.

Fats provide the highest calorie density at approximately 9 calories per gram. This is why traditional polar diets have always been fat-heavy: butter, pemmican, cheese, salami, and oils all deliver the most calories for the least weight. Carbohydrates and protein both provide roughly 4 calories per gram, less than half the density of fat, but you still need carbohydrate for hard hauling and protein for muscle repair.

In practice, polar expedition food targets a calorie density of roughly 4.0 to 6.0 calories per gram across the overall food supply: high calorie bars at around 4.5 sit inside that range, with butter and nuts above it. Foods below 3.0 calories per gram are generally too heavy to justify carrying. Water-rich foods (tinned goods, fresh fruit, bread) are almost never carried because they add weight without the calories to match, and many will freeze solid.

The balance between fats, carbohydrates, and protein varies by expedition style and personal preference. A common approach is roughly 50% of calories from fat, 35% from carbohydrates, and 15% from protein. Some polar travellers push fat intake even higher. Test the ratio thoroughly before the expedition: the polar ice is not the place to discover that your stomach cannot tolerate a high-fat diet under exertion.

What happens to food in extreme cold?

Food with water in it freezes, and food with little water stays biteable, so the water content of a food tells you most of what it will be like at -30°C. Many foods that work perfectly well on a UK hill become impractical or inedible on the ice.

The table compares common polar foods for calories and cold handling. The calorie and water figures are approximate per 100g, from typical UK food composition values, and grams are rounded to the nearest 5.

Butter carries about three times the calories of white bread for the same weight and holds far less water, so it goes hard rather than freezing into an ice-filled block. That is why butter and oil end up in almost every polar meal plan, stirred into porridge and dinner, while bread and fresh fruit stay at home.

Foods that freeze solid. Anything with significant water content will freeze. Bread, cheese, cooked meats, energy gels, and many commercial energy bars become rock-hard below -15°C. Biting into a frozen energy bar at -35°C risks cracking a tooth. A food you cannot bite is a food you will not eat, so it drops out of your daily plan.

Foods that become impossible to handle. Polar travellers eat during brief rest breaks while wearing thick gloves or mittens. Fiddly packaging, small wrappers, foods that crumble into tiny pieces, and anything requiring preparation become impractical. Food needs to be accessible quickly, edible with gloved hands, and consumable in a few minutes.

Foods that lose palatability. Taste perception changes in extreme cold. Sweet foods often become cloying. Monotonous flavours lead to food aversion over multi-week expeditions. Variety in flavour and texture is what keeps you eating enough, week after week.

The ideal polar food is calorie-dense, soft enough to eat at extreme low temperatures, available in multiple flavours to prevent palate fatigue, packable in a format that can be accessed with gloved hands, and still pleasant to eat after weeks of repetition. For more on how food texture affects ease of eating in demanding situations, see our guide to soft high-calorie foods.

How do you stop food freezing on a polar expedition?

You can't stop it entirely, so polar travellers keep the next few hours of food warm with body heat and leave the rest in the pulk. A chest bag or an inside jacket pocket keeps snacks far warmer than the air, which is the difference between food you can bite and food you have to suck on.

Do the cutting in the tent. Slice butter, cheese and salami and break chocolate into bite-sized pieces the night before, because doing it in mitts at -30°C is slow and cold on the hands. Fill a vacuum flask with a hot sweet drink each morning, and bag each day's snacks separately so you can see at a glance whether you are eating enough.

What do polar explorers eat in a day?

Most polar expeditions follow a structured daily pattern, and food is planned around it.

Breakfast is typically consumed in the tent before breaking camp. It needs to be high-calorie, quick to prepare, and warm if possible. The most common approach is a calorie-dense porridge made from oats, powdered milk, sugar, and added fat (often butter or coconut oil), prepared with boiling water from a stove. Some expeditions add protein powder, dried fruit, or nut butter. The goal is roughly 1,000 to 1,500 calories in a single sitting to provide the foundation for the day's travel.

Trail food is consumed during brief rest breaks throughout the day, typically every 60 to 90 minutes. This is where food must be accessible, edible in cold conditions, and calorie-dense enough to deliver real calories in a few bites. Common options include chocolate, nuts, salami, cheese, flapjacks, energy bars, and dried fruit, though many of these freeze at polar temperatures. Our ranking of the best energy bars for expeditions scores bars on cold performance as well as calories per gram. For ideas on maximising calorie intake through snacking, see our guide to high-calorie snacks.

Dinner is the main meal, consumed in the tent after the day's travel. Freeze-dried or dehydrated meals rehydrated with boiling water are the standard approach: they are lightweight, compact, quick to prepare, and provide a warm, satisfying meal. Many polar travellers add butter, oil, or cheese to increase the calorie content of their evening meal beyond what the packet provides.

Additional calories are often consumed as hot drinks (hot chocolate made with powdered milk and sugar, or soup) and as a pre-sleep snack. Some polar travellers also carry a thermos filled with a high-calorie drink to consume during the day's travel. For approaches to boosting calorie intake through drinks, see our guide to high-calorie drinks, smoothies and milkshakes.

Added up, a typical polar day is about 1,000 to 1,500 calories at breakfast, 2,000 to 2,500 from the snack bag over eight to ten breaks, 1,500 or so at dinner once butter or oil goes in, and a few hundred more from hot drinks. A weighed, meal-by-meal version of that day, with stove fuel, is set out in my Greenland crossing food plan.

Why does appetite drop in the cold?

One of the paradoxes of polar travel is that calorie requirements are at their highest just when appetite is often at its lowest. Cold, fatigue, altitude (on high-altitude polar plateaus), dehydration, and the psychological monotony of day after day of hauling across featureless terrain all suppress appetite.

This creates a dangerous feedback loop. Insufficient calorie intake leads to greater fatigue, which further suppresses appetite, which leads to a growing calorie deficit that compounds over days and weeks. By the time the deficit shows (as significant weight loss, reduced performance or poor decisions), it may be difficult to recover.

The solution is disciplined eating: consuming food on a schedule regardless of hunger, choosing foods that are easy to eat when appetite is absent, and ensuring that every food item carried delivers maximum calories for its weight so that the practical barrier to eating is as low as possible.

For a broader discussion of strategies for maintaining calorie intake when appetite is reduced, including smaller portions of more calorie-dense food, see our guide on low appetite and difficulty eating enough calories.

Where do Phoenix Bars fit on a polar expedition?

I make Phoenix Bars, so read this section with that in mind. They belong in the snack bag rather than at dinner: up to 557 calories in a compact, 120g bar, about 4.5 calories per gram, which sits inside the 4 to 6 calories-per-gram range polar food plans aim for. They won't freeze or melt, they break into pieces you can eat in mitts, and in the tent you can mix one with water for porridge. There are six flavours, which helps on a long trip when the same taste every day gets hard to face, and they keep for up to two years, so food can be bought and packed months before you fly.

Customers have taken them to the South Pole, across Greenland and into the Arctic, onto Himalayan peaks including Everest, Manaslu and Ama Dablam, and into winter races such as the Beyond The Ultimate Ice Ultra and the Winter Spine Race. The feedback I hear most often is that the bars were still soft enough to bite when other food in the same pack had frozen; one Ice Ultra runner said they did not freeze at all at -40°C. Climbers above 6,000m have also told me they were one of the few foods they could keep eating once their appetite had dropped.

A few of the reviews:

"Flaming Phoenix Bars featured as a star in my food supply for my recent South Pole expedition! Easy to eat, even at -45°C. Apple and cinnamon was a particular standout."

"Having tried many high-calorie flapjacks during my travels such as to the North and South Poles, I found this one really good, tasty and providing the calories, having just used it in Greenland."

"I used Phoenix Bars on a 5-day trek across Iceland and I enjoyed breaking off small pieces as they are really high in calories and because they aren't overly sweet."

For ways to use them as porridge, as a trail snack or alongside main meals, see how to use Phoenix Bars. Flavours and bundles are on the Phoenix Bars page.

How much food do you need for a polar expedition?

When planning food for a polar expedition, consider the following:

Calculate total calorie requirements. Multiply your target daily intake (typically 5,000 to 7,000 calories) by the number of expedition days, plus a reserve of at least 10 to 15% for delays caused by weather, navigation issues, or slower-than-expected progress.

Calculate total food weight. Divide your total calorie requirement by the average calorie density of your food supply. If your food averages 5.0 calories per gram, a 60-day expedition requiring 6,000 calories per day needs approximately 72kg of food, a significant proportion of total expedition weight. Add a 10% reserve and it becomes about 79kg.

Test everything before the expedition. Your digestive system, taste preferences, and tolerance for specific foods under exertion may be very different from what you expect. Test your complete food plan during training, ideally in cold conditions and under physical load. Discovering that you cannot tolerate your chosen breakfast porridge after three consecutive days is far better discovered during a training weekend than on day four of a South Pole crossing.

Plan for variety. Palate fatigue becomes a problem on any expedition lasting more than a week. Carry foods in multiple flavours and textures. Rotate snack options daily. Include at least one indulgent item, something that feels like a treat rather than fuel.

Account for packaging. Remove all unnecessary packaging before departure to save weight. Repackage into labelled zip-lock bags or similar. Make sure everything can be opened and accessed with gloved hands.

Frequently asked questions

How many calories do you need on a polar expedition? Most polar expeditions require between 5,000 and 7,000 calories per day, depending on the intensity of travel, environmental conditions, and individual body weight. Even at this intake level, most polar travellers lose weight over the course of a multi-week expedition.

Why do polar explorers eat so much fat? Fat provides 9 calories per gram, more than double the calorie density of carbohydrates or protein. When every gram of food must be carried or hauled, fat delivers the most calories for the least weight, and it is digested slowly, which suits long days of hauling.

What foods freeze on a polar expedition? Most foods with significant water content freeze solid below -15°C, including bread, cheese, energy gels, many energy bars, cooked meats, and fruit. Nuts and chocolate hold very little water, so they don't freeze, though they turn hard and brittle; butter goes rock hard but can still be cut into pats in the tent.

Can you cook on a polar expedition? Yes. Most polar expeditions carry a stove and fuel for melting snow (the primary water source) and preparing hot meals. Cooking is typically limited to breakfast and dinner, with trail food consumed cold during the day's travel. Fuel weight is a significant consideration, so meals that need only boiling water, such as freeze-dried or dehydrated meals, are preferred over those requiring prolonged cooking.

How do you prevent weight loss on a polar expedition? Significant weight loss is difficult to avoid entirely. The most effective strategies are maximising calorie density of food carried, eating on a disciplined schedule regardless of appetite, adding extra fat (butter, oil) to meals where possible, and choosing foods that remain palatable and easy to eat in extreme cold so that the practical barriers to eating are minimised.

What did early polar explorers eat? Early polar sledging rations were built on pemmican, dried meat pounded and mixed with fat, cooked with melted snow into a stew called hoosh and eaten with biscuits, butter, sugar and cocoa. Scott's polar party on the 1911 to 1912 South Pole journey ate about 4,400 calories a day while burning nearly 7,000, according to a 2012 analysis by Lewis Halsey and Mike Stroud. My guide to sledging rations covers what those rations held and how modern ones compare.

This guide is part of our series on nutrition for extreme environments. For related reading, see our guides to high-altitude mountaineering nutrition and ultra-endurance and expedition nutrition.

Written by James Frost, founder of Flaming Phoenix and the maker of Phoenix Bars. Updated November 2026.

Related guides

Fieldwork nutrition · Arctic Circle Trail food · Ski touring nutrition · Skiing calorie calculator

Sources: Stroud and others, European Journal of Applied Physiology, 1997; Halsey and Stroud, 100 years since Scott reached the Pole: a century of learning about the physiological demands of Antarctica, Physiological Reviews, 2012; McCance and Widdowson's CoFID 2021.