Food for Thought: Eating on Big Climbing Days

This is the first post in a short series I would like to write about fueling for climbing.  It focuses specifically on how to fuel for big climbs, in contrast to eating during training or recovery, which will be covered later. I am not a scientist, and I’ll try to avoid scientific terms where possible.  I will try to provide references for further reading at the end of each post.  In addition, I will continue to refer to both Training For the New Alpinism (House, Johnston), and A Paleo Diet for Athlete (Cordain, Frier)

First, a short summary of the ideas that follow for the attention-span impaired:

  • Specific nutritional goals will allow you train harder and climb faster and longer
  • Nutrition goals for climbing days are different than those for training days so as to maximize training benefit or climbing performance
  • On shorter climbs (less than 10 hours) carbohydrate replenishment is the most important goal, and can be done via high carb gels and bars.
  • As climbing missions get longer, a more balanced intake of macro nutrients that includes fat and protein is important.  At these climb durations, fat and protein (via muscle breakdown) are critical energy substrates that must be replenished.

Okay, so now on to the details on all of this.

Establishing nutritional goals

First, there are a number of goals I typically like to keep in mind as I decide what goes into my pack on the day of a big climbing mission.  These goals are:

  • maintaining (or even boosting) performance
  • enhancing recovery times
  • modulating training benefit
  • long-term health

Some of the above are pretty obvious.  For example, maintaining or improving performance has been the marketed goal of many performance drinks, bars, and gels for quite some time now.  To say they are obvious, however, doesn’t necessarily mean that people understand how to achieve them. I often am surprised when a climbing partner pulls out a block of cheddar cheese on a big one-day push or a high-intensity outing. If you are one of those people, then this article is probably for you 😉

Event days versus non-event days

As mentioned above, we’ll discuss nutrition for training periods and longer missions (i.e. multiple days) in future blog posts, but in order to provide some clarity, I want to introduce the idea of ‘event’ days and ‘training’ days.

The idea is that each day out is either a ‘training’ day (‘non-event’ day) or a ‘climbing day’ (‘event’ day).  For example, in the past 3 months, I’ve had major climbing objectives, like the Nose in a day, and smaller, training days, which have included anything from a moderate hike with friends to Shune’s Buttress in Zion.  On the Nose, we were climbing for 14.5 hours straight.  Maintaining our pace was critical. On the latter objectives, the focus may have been building the metabolic engine, building strength, or improving technical climbing ability. 

Using this “event day” versus “training day” vocabulary mirrors some of the language from A Paleo Diet for Athletes, and it can help prioritize between various goals listed above. It also reflects a strategy presented in Training for the New Alpinism, where in the authors recommend avoiding carbohydrate rich bars and gels before low-intensity training and climbing (p. 291).  This recommendation is based on the premise that our fat stores are much larger, and we can do a lot more total work if we have a strong fat-burning metabolism.  Don’t worry about those specifics for now, just understand that the food you eat during training modulates the training benefit (specifically your ability to use fat as fuel).

Nutritional needs for climbing days (or “event days”)

Let’s stay focused on big climbing days in particular.  To understand the nutrition needs for various climb durations, I’ll refer you back to a post where I summarized my conclusions from A Paleo Diet for Athletes. 

Here are summaries of the ideas presented in those books.

Shorter climbs (3-10 hours) 

On shorter climbs, particularly those lasting only a few hours, you are most often using sugar (muscular glycogen and liver/blood glucose) as fuel for high-intensity or powerful movement.  This is possible because you aren’t going to be moving for that long. Nutritional goals for this event duration will be to replenish carbohydrates and take in water.  This is something we can started doing immediately, and is best done through easily digested forms of space food (simple, carb rich gels, etc) and sports drinks.

Longer climbs (10-15 hours) 

As climbs get longer, we naturally reduce the pace of our movement in order to preserve energy and avoid bonking.  Think about it: if you are going for a 12 hour hike, you don’t slam it out of the gate.  If we acknowledge that we are moving at a slower pace, what does that mean about the needs of our bodies?  Well, if you have a well-established fat-burning metabolism, then you are going to be burning a lot more fat and a lot less sugar (stored carbohydrate).  Though this is the case, our goals for fueling won’t actually be that much different from climbs of shorter length; you still want to consume carbohydrates to replenish those that you are burning.  The difference comes via a shift to focusing on ‘real’ foods instead of gels.  This is where I often replace high-carb performance foods with trail mix, dried fruit, and the like.   This is possible because the intensity level won’t inhibit us from digesting these types of foods.

Full days (15+ hours) 

This is where nutrition needs can change substantially. To move for this long, you NEED to be able to rely on burning fat (and even in the 12-16 hour duration, really). Your body just simply cannot store enough carbohydrate to move at a high-intensity level for this long.  At this event duration, several other interesting things begin to happen.  First, your body begins to use protein as fuel at a reasonable amount (10-15%)1,3, and second, your body may begin to breakdown muscle in order to reduce high blood acidity levels1.  Triathletes have known about these effects for years and it is called protein catabolism. It is why your pee after a really long day (and most of the top of El Capitan) smells like ammonia4.

*A caveats to the above: estimated event durations may vary based on various levels of fat-adaption in athletes, and intensity of climbs. 

The food I brought on moderately long day on Tatooine and dinner afterwords. Some of my favorite bars, plus a mix of nuts and homemade energy balls in the plastic bag. For dinner we did sardines and a thai spaghetti meal that had some fiber and added sugar (as it seems all process food does these days).
The food I brought on moderately long day on Tatooine (10 hours or so) plus what we had for dinner afterwords. Some of my favorite bars, plus a mix of nuts and homemade energy balls in the plastic bag. For dinner we did sardines and a thai spaghetti meal that had some fiber and added sugar (as it seems all processed food does these days).  Overall, I had 3 bars on the climb for total of about 1000 calories – more would have been nice but I packed poorly!

So, what do exactly you eat?

The following table summarizes the information above and provides some examples of the best foods to eat. Keep in mind that this table is for what to eat on climbs where you are really looking for your best performance or aiming to beat the clock (which often means avoiding weather, nightfall, or objective dangers in the alpine climbing world).

3-10 hr -150-300 calories/hr

-High carbohydrate ratio (4:1 carb to protein)

Gels and easily-digested carbohydrate rich bars -Gels (those that include BCAAs are good).



-Dried fruits like dates, figs, and raisins (all high in potassium and sugar).

-Chocolate covered espresso beans!!!

10-15 hr -150-300 calories/hr

-High carbohydrate ratio with slight increase protein

-Ideally include BCAAs via protein sources

Bars, trail mix, and gels if necessary given intensity level. Bars should contain a moderate amount of protein. -Reddbars (super clean and high quality, lots of nutrients), Probars, Chapul bars are all good choices, they contain some protein in addition to a moderate to high levels of carbohydrates.

-Trail mix (nuts with a good amount of chocolate or berries).

-Dried fruits like dates, figs, and raisins (all high in potassium).

-Gels that include BCAAs.

Full days (15+ hrs) -150-300 calories/hr

-Increase in fat and proteins compared to above.  Fat should make up 1/5 to 1/3 of calorie intake.

Same as above, but increased intake of BCAAs and other nutrients beyond sugar becomes increase important. Real foods as they are more easily digested at this intensity level. -Reddbars, Probars, Chapul bars are all good choices, they contain some protein in addition to a moderate to high levels of carbohydrates.

-Trail mix (nuts with a good amount of chocolate or berries).

-Small bits of animal proteins (smoked salmon, sardines, jerky)

Circling back to our nutrition goals

At the beginning of this article I mentioned five goals that should be kept in mind when deciding what to eat.  Let’s briefly discuss how the above recommendations relate back to those goals, and what else you might want to keep in mind when choosing what to eat.

  • Again, why so many carbs? At high-intensity levels you are burning through limited glycogen stores quickly.  Taking in an increase load of carbohydrates helps both from a performance standpoint (making more sugar available) and from a recovery standpoint (allowing your body to immediately begin to restore glycogen for the next day or climb).
  • Why the focus on BCAAs (and protein)?  Branched chain amino acids are the building blocks for muscle repair so their availability enables your body to recover more quickly as you breakdown muscle.  Consuming BCAAs and protein also allows your body to use these instead of breaking down muscle to fight blood acidity.  Overall, the consumption of protein during long duration events is extremely important to maintaining strength, especially when climbing multiple days in a row.
  • What about performance vs. training effect? It’s important to consider that eating bars and gels every day and running a carbohydrate-rich diet during training and climbing can be hard on your health.  This is something I’ll get into during the next post when talk about what to eat while training, but consider that many of the food items identified in the table above drastically spike insulin due to the lack of fiber.  This “event day” diet is not something you should be eating every time you go out climbing.  Rather, it is a diet meant to allow you to perform at a high-level on select days. When training, we can push our bodies to build a fat burning metabolism by avoiding carbohydrate loading before, during, and after exercise. Maybe you are beginning to see the trade-offs between an “event day” diet and a “training day” diet.

More on calorie intake, water, other practical considerations

Of course, climbing fast and constant movement means that we don’t always get to choose when we eat.  Often, the pack which contains the food might even be with the follower. As solutions to both these problems, I always carry food in my pocket; typically what I expect to consume over the next three hours.  This gives me the opportunity to grab a quick bite whenever is convenient (often at a belay).

The other challenge I personally deal with sometimes is my ego: “no I don’t need to eat right now”.  The challenge is that while you might not feel hungry now (you body is creating hormones that signal it is not the time to eat), it is hard to start replenishing electrolytes and glycogen TOO earlier.  Eat a bar anyway.

Taking in water with food is important, as it helps us to digest the food, and actually prevents us from becoming dehydrated. Cordain posits that our water intake should be 6-8oz for every 100 calories consumed. While I am not always strict on measuring how much water I am consuming, I do like to have a carrying system that provides the chance to track it if necessary.  For example, on the NIAD, Jimmy and each had a .5L bottle on our harnesses for each 3 hr block.  In this case, I knew exactly how much water I was consuming each hour. This system helped to ensure that we always were drinking a little bit. 

Putting it all together

I put together all the above information because I really believe in the ability to improve the way we think, train, and climb through a better diet.   I personally have seen huge differences with both my performance and my mental attitude as I have narrowed down on what works for me on big climbs. Hopefully the above information gives you something new to think about as you pack your bag for your next big day.   Take some of the above suggestions and see what works for you.  Good luck and more on the best dietary habits for training soon!

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