Nutrition Demands for Ski Touring Performance and Safety

If you’ve ever had the pleasure of setting a bootpack in deep snow, you know how many calories it requires. Sawtooth Mountain Range, Idaho. Photo:Jackson Long

As much as we plan for our fitness and gear and conditions, good nutrition makes for a better day out. Here are some steps and ideas to get you thinking about fueling your tours. 

Whether you casually or intensely backcountry ski, it is a highly demanding sport. While the touring culture promotes excellence in performance and safety, nutrition considerations are often ignored. As a performance nutritionist and ski coach, I’m keen to educate the community to optimally fuel our time in the skintrack to better equip us for the performance and safety demands.

Now that the snow is finally falling here in the West, it’s time to dust off the skis, put some fresh batteries in our avalanche beacons, and get amped for powder turns and lofty objectives. In addition to getting our gear dialed, I argue it’s just as important to think about fueling the epic days in the mountains so we can feel our best. Here are a few steps to get you started.

Step 1: Understanding the nutrition demands of backcountry skiing

Ski touring is a unique sport in that it can be an all-day affair with a mix of uphill “skinning” to reach the slope we want to ski, followed by a short and sometimes intense effort on the descent, which requires a significant amount of strength. Depending on your objectives and experience, backcountry tours can range from a couple of hours to borderline ultra-endurance feats. Many athletes (myself included) are drawn to this because of its special combo of aerobic endurance, strength, and technical capacities, plus a healthy dose of adrenaline and connection with the serenity of a snowy mountain landscape. It’s a hard but beautiful sport.

While this effort is usually relatively low in intensity, the body still uses a lot of energy (calories) to power this movement, including carrying our skis and packs up and down the hill. For new skiers especially, it’s easy to push into a higher work rate, demanding more energy from carbohydrates stored in our muscles as glycogen, which becomes depleted much quicker than our fat stores. So, while we’re primarily using stored fat to generate the energy needed for those long, slow skins, carbohydrate metabolism is ongoing—anytime the effort gets bumped up and our breathing rate increases, we’re tapping into those precious muscle glycogen stores. Snacking on carbohydrate foods will help spare their depletion.

Additionally, exercising in the cold demands even more energy use due to our body having to produce extra heat, with a preference for using carbohydrates stored in our muscles to keep us moving under the stress of cold (activated by our sympathetic nervous system). Plus, where there’s skiing, there’s often high altitude, which potentially increases energy needs. Venturing into the mountains in winter means we must fuel properly to avoid that bummer hypoglycemic “bonk,” which risks running our glycogen tank too low, impairing our mental processes since our central nervous system relies heavily on glucose. Any situation that impairs our decision-making skills is problematic in potentially risky situations like backcountry skiing. Hypothermia is also a risk in cold environments and becomes exacerbated by hypoglycemia, which can cause a whole host of other issues.

Packing some dense real food snacks is paramount to a good time in the alpine. Sawtooth Mountain Range, Idaho. Photo: Jackson Long

Energy requirements are even higher for those athletes working extra hard training for a ski mountaineering objective or a skimo race. Like many endurance athletes, this means stacking on a significant training load from a volume and intensity perspective. This training uptick requires a significant energy intake, and in my experience working with a number of these athletes, it’s a challenge to meet the requirements consistently.

The moral of the story is that prioritizing fuel as part of your backcountry tour planning is essential for good performance, enjoyment, and safety. 

Safety

One area that isn’t discussed much in the context of backcountry ski safety is how critical a role proper nutrition plays. Good decision-making requires a good flow of glucose to the brain and the energy to react/respond when and if shit hits the fan. From keeping core temperature and hydration status in balance to having the energy to make it home after an all-day adventure, food is quite literally fuel.

Dialing in your fueling for this kind of skiing transcends pure performance—it’s also a major safety consideration. It’s a good habit to build a plan for your tours.

Deep in the backcountry, simply getting to the start of your ski line is a serious effort. Sawtooth Mountain Range, Idaho. Photo: Jackson Long

Step 2: Make a Plan

An essential habit any avalanche safety course will espouse is the importance of making and sticking to a plan when heading out into the backcountry. Knowing and interpreting the avalanche report and weather, making a route plan with your partners, and having the right safety equipment (and the knowledge of how to use it) and the appropriate gear are critical for having a positive and safe experience.

The same goes for nutrition, but as with so many athletes, we often invest little thought into this aspect of planning. Failing to plan is planning to fail.

I like to go through a series of questions, similar to the gear, weather, and clothing demands:

How long will I be out there?

Duration and intensity are the two main factors determining food requirements during exercise. There is a big difference in what and how much to eat if you’re out for 2 hours vs. 8. Proper fueling for these durations comes with experience and understanding your route, but err on the side of overestimating how long you’ll be out and plan accordingly. For endurance activities like skiing, a good general guideline is taking in roughly 150-240 calories per hour if you’ll be moving for over 90 minutes, so you can work backward and estimate how much you might need. In the next section, I’ll give practical examples.

How intense will it be?

Am I going for a hard effort or a big objective? Or is it a long and slow Sunday cruise with friends? The higher and/or longer the effort, the more food you need, and the more emphasis on carbohydrate-rich foods to keep energy levels high while skinning. The day’s workout or tour may also change hydration needs, as the harder we work, the more we sweat, and we may want to bring some electrolytes. Terrain, altitude, and environment also dictate intensity; routes with many transitions and/or changes in gradients, hard bootpack sections, and heavy/fresh/deep snow affect how hard we must push for a given pace. Fuel accordingly.

How much room do I have?

Something worth mentioning is the space and weight of the nutrition we haul on our tour. It’s a balancing act to pack light enough not to get over-encumbered and carry a bunch of extra weight up, sometimes thousands of vertical feet, but also have everything you need for a day out. Warm layers, avalanche equipment, water, and food add up quickly. Sometimes, we have to sacrifice something to fit the essentials, and if the goal is ultra-light travel, there are ways to maximize calories per space taken up. Learning how to do this is part art and part science. More on this in a bit.

What time am I leaving?

A key part of the nutrition plan should focus on what you eat for breakfast. Particularly for those early morning dawn patrol missions, having something to eat is critical so you aren’t starting in a deficit. Our blood sugar drops during the night, so having even a small meal, like a piece of toast with peanut butter and jam or some granola with banana, can give you that little boost to start the day with a topped-up tank. It also helps spare the precious energy stores in our muscles that we’ll want to save for the final summit push summit. I’m a big fan of packing overnight oats in a Tupperware container the night before those early morning drives into the mountains, especially in preparation for the big days out when you might need the extra fuel and have some time to digest.

My favorite adventure fuel: loaded oats and coffee. Jet fuel for the big mountains. Photo: Jackson Long

Step 3: Organize the food kit

Once you envision the day’s plan, I recommend putting together a “kit” of your snacks for easy access in your pack. It doesn’t have to be super complicated or time-consuming. If it’s a long day— more food; shorter—less, etc. I like using a big Ziplock freezer bag or stuff sack and having snacks accessible on the side pockets of my pack or even in a jacket pocket close to my body for colder days. Make your snacks easily accessible while on the go; it doesn’t ultimately matter how many snacks you have if they remain uneaten because they’re buried in your pack.

A good starting point is choosing familiar foods that are easy to eat and digest when temps are cold. They should also be easy to access and eat while wearing gloves and not take up excessive space in our packs. A crumbly homemade muffin might be super delicious, but the ratio of muffin that falls on the snow rather than in your stomach isn’t nutritionally favorable. Same with bananas; I’ve had too many explode in my pack to consider them worth bringing.

When in doubt, a good rule of thumb to start off with when packing is to think about bringing 1-2 “servings,” i.e., one to two of these items, for each hour you anticipate being out there and snacking early and often.Here are some of my favorite snacks:

• dried mango or figs
• PB&J sandwich or tortilla wrap (a tried and trued classic)
• PRO bar meal bars (dense in calories and nutrition in a pretty small bar)
• leftover pancakes
• homemade date, oat, and peanut butter-based energy bars or cookies
• nut butter packets
• local pastries (not crumbly though)
• Larabars or other simple/real food bars
• nuts/trail mix
• an emergency stash of gels/blocks/Swedish Fish

Favorite pre-tour breakfasts:

• overnight oats or warm oatmeal (if there’s time to make)
• muesli or granola with yogurt
• tofu or egg and potato scramble burrito/bagel
• toast with PB and sliced banana, maple syrup drizzle
• if scrambling for time, some kind of bar like a Larabar or PRO bar
• coffee. Lots of coffee.

Of course, these are just a few options I enjoy, so experiment and find what works for you. I usually try to mix it up with sweet and savory for the long days to prevent palate fatigue and bring some treats (like a cinnamon roll) or proper lunch items for the obligatory lunch break at the summit—gotta keep morale high.

Pro tip: pack an extra sandwich or stash of food in the car for the ride home.

Summit snack time = the best time. Photo: Jackson Long

You’ll also notice that these suggestions are generally “real food” based and balanced in their macronutrient breakdown. Quick-burning “sports foods,” like processed gels/blocks/bars, etc., are great for intense activities where we strain the digestive system and absolute energy needs are high. But real food is where it’s at for long, relatively slow days in the mountains. Choose those quick-digesting, simple carb-based snacks for the more fast-paced, skimo-type sessions or as a backup if you feel that bonk coming on.

Carbs vs. fats: what’s the deal?

Carbs are a key fuel source anytime we’re exercising, but we can and should also call upon using fat as a fuel source when we’re moving relatively slowly and at a low intensity. Fat provides more than double the calories per gram as carbohydrates, which makes it ideal when trying to maximize space in our packs or going for a very lightweight setup. Things like nut butter packets are a fantastic and minimal way to get fuel in the tank.

There’s a lot of talk around the concept of “fat adaptation,” where the body’s metabolism becomes better equipped to use fat as a fuel source to spare the precious and limited carbohydrate stores. This adaptation can happen through a couple of different processes. Primarily, it occurs by becoming more aerobically fit and spending a lot of time doing low-intensity endurance training. Another method to train fat adaptation is restricting carbohydrates in daily eating and training or completing workouts in the fasted state. However, over-emphasizing the importance of this through restricting carbohydrates compromises your ability to use both carbs and fat as fuel efficiently and undermines the quality of training. It’s a much better approach to focus on fueling our touring days well so we can do more training in general and improve our aerobic fitness and metabolic flexibility.

A word of caution: if you’re not used to eating high-fat foods while moving, it’s a good idea to start small and experiment, as it takes longer to digest these foods than carbohydrate-rich ones.

Step 4: Hydration

Last, but, far from least: the other major nutrition consideration while out in the backcountry is hydration. For several reasons, it’s easier than you might think to become dehydrated in the winter.

1.  It’s cold, which can lessen thirst and drive to drink. Plus, typical bottles, bladders, or soft flasks are prone to freezing, rendering them useless.
2.  The air is drier than in temperate months.
3. We’re often at higher elevations than normal, increasing our fluid needs.
4. We’re working (and breathing) hard on the uphill, getting cold while transitioning, and then warm again while descending. These big swings in temperature mean our body is working harder to keep our core temperature regulated, resulting in heat and sweat loss. Unless you’re a layering god or goddess, perfectly regulating temperature out there can be challenging.
5. When exposed to the cold, our blood vessels constrict to protect our core temperature, increasing blood pressure and causing the kidneys to push more urine into our bladder and making us pee more often, known as “cold diuresis.” This contributes to more water loss than normal and is important to remember.
6. During the spring skiing season, where large temperature swings are the norm, it’s easy to sweat A LOT when out in the mountains. It’s likely still dry and at high altitudes, so fluid needs will also be high. If you’re a heavy sweater, it’s probably a good idea to have some electrolytes with you.

It’s important to prioritize our hydration in addition to eating and recognizing that even though we may not feel thirsty, we’re losing lots of fluid and electrolytes through our sweat and breathing. Being dehydrated in the backcountry becomes a safety risk, with impaired decision-making and concentration. Like with food, sipping early and often is the key to success.

I recommend bringing two bottles, one with water or an electrolyte drink and one insulated bottle with a warm drink to help keep the core temperature high.

Parting Thoughts

It’s important to zoom out and remember that the point of getting out into the mountains is to have a fun experience, find some flow, and connect with the natural world through meaningful movement. We want to feel great all day, not on the verge of bonking and dragging on that final run on that epic powder day because we forgot to eat breakfast or bring snacks. We want our minds and muscles fueled and sharp in high-risk situations. Fueling matters. It’s a tool for creating those rich experiences, just like our fancy lightweight skis and boots (but much cheaper).

It also makes sense to prioritize fueling our brains in potentially risky situations, such as venturing into avalanche terrain. If our brain and muscles run low on fuel, it becomes harder to a) make good decisions and b) be ready for action if something happens.

So whether you’re going out for a before-work tour or a weekend yurt trip, get your snacks ready and some tea in the thermos; it’s go time.