Ski touring and ski mountaineering burn enormous calories in conditions that make eating difficult. Most energy bars freeze solid below 0°C. This guide covers how to stay fuelled when the cold is working against you.

In this guide

• Why ski touring is nutritionally demanding
• The cold problem: why most trail food fails
• Why calorie density matters on a ski tour
• What makes food work in sub-zero conditions
• How Phoenix Bars can be used
• Fuelling strategies by tour type
• Frequently asked questions

About this guide

This guide explains the specific nutrition challenges of ski touring and ski mountaineering, where cold temperatures, high calorie burn, altitude, and limited pack space combine to make eating one of the hardest parts of the day.

For broader guidance on high-altitude nutrition, see the High Altitude Mountaineering Nutrition guide. For general ultra-endurance nutrition principles, see the Ultra-Endurance and Expedition Nutrition Guide.

Phoenix Bars are a high-calorie nutrition bar designed for situations where maximum calories in minimum weight is critical. They remain soft and edible in sub-zero temperatures.

Last reviewed: 2026

Ski touring is one of the most calorically demanding mountain activities. The combination of sustained uphill skinning, altitude, cold, and heavy equipment means a full day of ski touring burns 4,000 to 7,000 calories depending on terrain, elevation gain, conditions, and pack weight. On multi-day tours or hut-to-hut traverses, this demand repeats day after day.

The problem is not knowing you need to eat. Every experienced ski tourer understands that. The problem is that the conditions you are touring in actively conspire to stop you eating. Your food freezes in your pack. Stopping to eat means cooling down rapidly in wind and cold. Altitude suppresses appetite. Gloved hands cannot open wrappers. The bar you packed this morning is now a solid brick that could chip a tooth.

The result is a predictable pattern: strong start, good pace through the morning, then a steady decline in power and warmth through the afternoon as the calorie deficit accumulates. On a day tour, this means a miserable final descent. On a multi-day tour, it compounds until performance and safety are genuinely compromised.

This guide is for anyone who ski tours long enough and hard enough that nutrition becomes a limiting factor: day tourers, multi-day hut-to-hut ski tourers, ski mountaineers, spring haute route participants, and anyone who has eaten a frozen energy bar with their goggles fogged and their patience gone.

Why Ski Touring Is Nutritionally Demanding

Ski touring combines several factors that individually increase calorie needs and together create a significant fuelling challenge.

High energy expenditure. Skinning uphill with a loaded pack at altitude burns 600 to 900 calories per hour depending on gradient, snow conditions, pack weight, and body weight. A six-hour touring day with 1,200m to 1,800m of ascent burns 4,000 to 5,500 calories from the touring alone, on top of a baseline metabolic requirement that is itself elevated by cold and altitude.

Cold increases calorie burn. The body burns additional energy to maintain core temperature in cold conditions. This thermogenic effect adds 10 to 20% to calorie expenditure depending on temperature, wind, and how well insulated you are. In severe cold, the increase can be higher. This means calorie needs are elevated even during rest stops and at the hut.

Altitude suppresses appetite. Above 2,000m, appetite typically begins to decline. Above 3,000m, the effect is pronounced. Many ski tourers report being unable to face food at altitude despite knowing they need it. The body needs more calories at altitude (due to increased breathing rate and metabolic demand) at the same time that the desire to eat is reduced.

Stopping to eat means getting cold. On a skin track in wind, every minute you stop is a minute you are cooling down. Eating requires removing gloves, opening wrappers, and standing still. In windy or exposed conditions, this creates a strong disincentive to eat, and many tourers skip food stops to avoid the chill. The result is a calorie deficit that builds invisibly until performance drops.

Sweating under layers creates hidden fluid and calorie loss. Skinning is hard physical work. Even in cold conditions, tourers sweat heavily under multiple layers. This fluid loss reduces appetite and can mask the early signs of calorie depletion. By the time you feel hungry, you are already significantly behind on intake.

The Cold Problem: Why Most Trail Food Fails

This is the single biggest practical issue with nutrition on a ski tour, and it is the reason most standard trail food is inadequate.

Below 0°C, most standard energy bars become rock-hard. The binding agents in typical bars (honey, syrup, chocolate) solidify in cold. A bar that is soft and chewy at room temperature becomes a solid block that cannot be bitten into, let alone chewed, at -5°C or below. Many tourers have tried to eat frozen bars and either given up or risked dental damage.

Energy gels have a different problem: the packets become nearly impossible to open with cold or gloved hands, and the gel itself thickens in cold temperatures, making it slow to consume. Some gels freeze entirely.

Chocolate freezes solid. Cheese becomes hard. Nuts are fine but deliver limited carbohydrates. Sandwiches freeze and become unpleasant to eat.

The workaround most tourers use is to store food inside their jacket, close to their body, to keep it warm. This works for small items but is impractical for carrying a full day's food supply. It also means food is only accessible when you stop, remove layers, and dig around in your clothing, which adds time and cold exposure.

The ideal solution is food that simply does not freeze. Food that remains soft, chewable, and edible at any temperature you are likely to encounter on a ski tour removes the problem entirely.

Phoenix Bars remain soft and easy to eat at temperatures as low as -45°C. This is not a theoretical claim. They have been used on polar expeditions in extreme cold and remained fully edible.

"Flaming Phoenix Bars featured as a star in my food supply for my recent South Pole expedition. Easy to eat, even at -45c."

Why Calorie Density Matters on a Ski Tour

Calorie density is how many calories a food delivers per gram. On a ski tour, it determines how much energy your food provides relative to the weight in your pack.

Pack weight matters enormously in ski touring. Every gram on your back is a gram you skin uphill. Heavy food means slower skinning, more fatigue, and higher calorie expenditure, which means you need even more food. The cycle is self-defeating.

A standard energy bar delivers 150 to 250 calories in 40 to 60g. A Phoenix Bar delivers up to 557 calories in 120g, roughly 4.6 calories per gram. To carry 3,000 calories of on-tour food, you would need twelve to fifteen standard bars (600 to 900g) or fewer than six Phoenix Bars (720g) delivering significantly more total calories.

On a multi-day hut-to-hut tour where you carry food for several days between resupply, the weight saving compounds. Ten Phoenix Bars (1.2kg) provide 5,570 calories. The equivalent in standard bars would weigh nearly twice as much for the same energy.

When you are skinning uphill at altitude with a heavy pack, every gram matters. Higher calorie density means less weight for the same fuel.

What Makes Food Work in Sub-Zero Conditions

The requirements for ski touring food are specific.

Does not freeze. This is the non-negotiable starting point. If you cannot bite into it at -10°C, it is dead weight in your pack. Food that remains soft and chewable across the full range of temperatures encountered on a ski tour is essential.

Edible with gloves on. Removing gloves to eat means cold hands, dropped food, and wasted time. Food that can be eaten while wearing liner gloves or thin ski gloves, or that can be broken into pieces and eaten from a pocket, is far more practical.

High calories per gram. Less weight means faster, easier skinning and less fatigue. Higher calorie density means more energy for less pack weight.

Provides sustained energy. Skinning is a sustained aerobic effort lasting hours. Food that combines carbohydrates with fat and protein delivers both fast and slow-release energy, supporting consistent output over a full touring day rather than the spike-and-crash of pure sugar.

Not excessively sweet. On a long, cold day, intensely sweet food becomes unappealing. Milder, more neutral flavours sustain appetite across repeated eating events. This is especially important on multi-day tours where you are eating the same food day after day.

Compact and durable. Food needs to survive being packed into a ski touring rucksack alongside skins, crampons, a shovel, and a probe without being crushed. Water-resistant packaging is a bonus in snowy conditions.

How Phoenix Bars Can Be Used

Most energy bars freeze solid below 0°C. Phoenix Bars do not. They have been eaten at temperatures as low as -45°C and remained soft enough to bite into without risk to your teeth or your patience. On a ski tour, they can be pre-broken into pieces and stored in a chest pocket for continuous eating without removing gloves, or mixed with hot water from a flask at a hut for a calorie-dense porridge that delivers both warmth and energy simultaneously.

On the skin track. Break a bar into pieces before setting off and store them in a chest pocket or hip belt pocket. Eat a piece every 20 to 30 minutes without stopping. This keeps calories flowing in steadily without the need to stop, cool down, remove gloves, and rummage in a pack. A full bar consumed over 90 minutes delivers roughly 370 calories per hour.

At transition points. When you stop to remove skins, put on a jacket, or regroup, eat a half or full bar alongside water. Transitions are natural eating opportunities because you are already stopped. Use them.

At the hut. If the hut has hot water or you are carrying a flask, make a Phoenix Bar porridge for a 557-calorie hot meal in two minutes. On a hut-to-hut tour, this can serve as a quick breakfast before an early start, or as a calorie boost on arrival before the evening meal.

In the emergency kit. A single Phoenix Bar provides 557 calories of shelf-stable, freeze-proof emergency food. If conditions deteriorate, a tour takes longer than expected, or someone in the group runs out of energy, it is immediately available and edible regardless of temperature.

"From my experience (having raced three times around the world, winning the BT Global Challenge and becoming the fifth British sailor in history to complete the Vendee Globe), I think these flapjacks are well-suited to challenging, long-distance water sports, such as offshore sailing."

[Ethan (parOARmedics)] "They've been particularly great when I've been seasick and they're all I can eat!! My team and I have ordered loads of these for our Atlantic row later this year!!"

Full nutritional information and ingredient lists for all six flavours are available on the product page.

Fuelling Strategies by Tour Type

Day tour (single ascent and descent, 4 to 6 hours). Pack two Phoenix Bars (1,114 calories, 240g) alongside water and whatever else you carry. Break the first bar into pieces before you start and eat them steadily on the ascent. Eat the second at the summit or during the transition. This provides a reliable calorie backbone without needing to stop for a formal food break.

Long day tour (multiple ascents, 6 to 10 hours). Pack three to four bars (1,671 to 2,228 calories). Eat portions consistently throughout the day. Supplement with whatever you eat at huts or shelters. The key is not waiting until you feel hungry. On a long cold day, hunger signals are suppressed by altitude and cold. Eat on a schedule, not on appetite.

Multi-day hut-to-hut tour (3 to 7 days). Pack three to four bars per day for on-tour food. Hut meals provide dinner and often breakfast, but the hours between are your responsibility. Phoenix Bars provide the calorie-dense, lightweight, freeze-proof trail food you need between huts. For a five-day tour, fifteen bars (1.8kg) provides 8,355 calories of guaranteed fuel regardless of what huts offer.

Ski mountaineering (technical terrain, long approaches, high altitude). The demands are the highest here: sustained effort at altitude with heavy technical kit. Calorie needs can exceed 6,000 per day. Pack four to five bars per day and eat aggressively. At altitude, appetite will be suppressed. Do not wait for hunger. The porridge format is useful if you have a flask or can access hot water, as warm food is easier to eat at altitude and aids morale significantly.

Spring touring (warm approaches, cold summits). The temperature range in a single day can span 15°C in the valley to -10°C at the summit. Food needs to work across both. Phoenix Bars do not melt in warmth and do not freeze in cold, making them reliable across the full day without needing to adjust your food strategy for elevation.

Related Guides

• High Altitude Mountaineering Nutrition
• Ultra-Endurance and Expedition Nutrition Guide
• Hiking and Trekking Nutrition
• Cycling and Bikepacking Nutrition
• UK Ultra Race Nutrition
• How To Use Phoenix Bars
• Calorie-Dense Foods: What They Are and When They Help

Frequently Asked Questions

Do Phoenix Bars really not freeze?

No. Phoenix Bars remain soft and edible at temperatures as low as -45°C. They have been tested on polar expeditions in extreme cold. The oat and coconut oil base does not harden in cold the way honey, chocolate, and syrup-based bars do. This is a genuine product differentiator for cold-weather use.

How many calories do I need per day ski touring?

A full day of ski touring with significant ascent burns 4,000 to 7,000 calories depending on terrain, altitude, conditions, pack weight, and body weight. You will not replace all of this through food alone. The goal is to minimise the deficit enough that performance and safety are maintained. Budget 2,000 to 3,000 calories of on-tour food per day, supplemented by hut meals.

How many Phoenix Bars should I carry per day?

For a standard day tour, two to three bars (1,114 to 1,671 calories). For a long day or ski mountaineering objective, three to five bars. For multi-day hut-to-hut tours, three to four bars per day for on-tour food, with hut meals covering breakfast and dinner.

Can I eat Phoenix Bars with ski gloves on?

Yes. Break a bar into pieces before you start, or bite directly into the bar. The soft texture means it does not require the grip strength or dexterity that frozen bars demand. Storing pre-broken pieces in a chest pocket means you can eat without removing gloves at all.

How do Phoenix Bars compare to other ski touring food?

Most standard energy bars freeze below 0°C and become inedible. Chocolate freezes. Gels thicken and packets are hard to open. Nuts are cold-resistant but low in carbohydrates. Phoenix Bars deliver 557 calories with a mix of carbohydrates, fat, and protein, remain soft in extreme cold, and do not require body-heat storage inside your jacket. For cold-weather touring, they solve the single biggest practical nutrition problem.

Buy Phoenix Bars

If you have any questions about using Phoenix Bars for ski touring or ski mountaineering, contact me directly. I am always happy to help.

James Frost

Founder, Flaming Phoenix

jfrost@flaming-phoenix.co.uk

07990 519422