Counting Calories, Calories That Count (Part 3)

“Hiker Hunger” is a well known—almost expected—aspect of long backpacking trips. In our experience, Hiker Hunger actually comprises two elements that often manifest in tandem, but don’t have to. The more subtle component is that, no matter how much food you carry, you still end up lusting after fresh food that doesn’t come out of a packet or require rehydration. It actually takes a long time—months—for a healthy adult who eats a varied diet in their daily life to deplete the many micronutrients such as vitamins required to maintain good health. This could be a consideration for through-hikers on the trail for many months at a time; micronutrient depletion, however, is not the reason why backpackers start fantasizing (and rhapsodizing if anyone is around to listen) about fresh salads and fried chicken on the fourth day of their hike. It is a psychological issue, in other words.

 

The other component of hiker hunger comes from running an actual caloric deficit leading to true physiological hunger. In addition to simply making you feel intensely hungry (and grouchy), consuming insufficient calories on trail can have genuinely negative—even dangerous—effects such as poor sleep and sleeping cold, fatigue, increased susceptibility to hypothermia, and decreased mental acuity. This physiological aspect of hiker hunger can, however, be addressed by carrying and eating a sufficient number of calories.

 

It’s that tricky little word, “sufficient,” that causes the problem when trying to balance calories in with calories out. “Calories in” is straightforward to calculate: all packaged food states precisely how many calories are in a serving and for things you make at home like oatmeal or trail mix, you can take a little bit of time to add up the ingredients. So far so good. It’s the “Calories out” bit that causes problems. If your assumption about the number of calories you’ll expend is off, you will end up either carrying too much or too little food for a given trip. For a relatively short trip you can just gut it out, whether that means feeling hungry or coming out with excess food; for a trip with a resupply, you might be able to adjust a bit as you go. For a long unsupported trip like ours on the HST, however, getting the daily calorie target at least close is important.

 

As I noted in Part 2, our daily calorie targets were “off.”

 

Specifically, despite our best laid plans and detailed calculations, the targets for both of us proved to be about 15% too high.

 

After our experience on the Uinta Highline trail where we were too high by about 30% (allowing us to stretch a 10-day plan to 12 trail days and accommodate the freak late-season snow that fell), we had reduced our planning targets significantly. We also had a fair number of trail miles and nights in the intervening three years to trail-test different targets, so we went into our High Sierra Trail adventure fairly confident that we were carrying the right amount of food for a nine-day unsupported backcountry trip at altitude.

 

The most relevant experience for me came from the results of an 11-day trip I did in 2022 in Kings Canyon with Andrew Skurka’s guiding company. I am not normally a “joiner” but I wanted to gain experience traveling and navigating off-trail and doing so with a program geared specifically towards those skills made sense.

 

We had a resupply halfway through that trip so we were only ever carrying at most five days worth of food. We spent much of the trip off-trail, tackling portions of the classic Sierra High Route and Skurka’s own Kings Canyon Basin High Route. The hiking was strenuous and the 3700 calories per day I used as my target turned out to be spot on. (In fact, I ended up consuming snacks from a just-in-case “bounce bag” I packed with a little bit of extra food.)

 

For our High Sierra Trail planning, I decided to ramp from 3400 to 3700 calories per day over the first few days as our planned distances got longer and elevations higher. But I also decided not to simply eat to the plan–I wanted appetite to truly guide what I consumed. If I felt full after dinner, then I’d skip dessert and hot chocolate, for example. Vienna set her target at about 85% of mine. We then assembled our meal plan, shopped, and packed accordingly.

 

For whatever reasons—lower altitude, mostly on-trail mileage, underlying changes in physiology, whatever—both of us ended up eating less than our plan for the first four days of the trip. As the weather cycle unfolded during those early days, it became clear that our planned summit day for Mt. Whitney would be stormy. We laid out all of our food at Junction Meadow, reset our expectations for caloric need based on what we had experienced to that point, and determined that we could stretch our time on trail to 11 days and summit Whitney in the clear. So that’s what we did.

 

This experience marks the second time that we ended up carrying more food on a long unsupported trip than what our initial trip plan would have needed. That said, in both cases, that “error” allowed us to make on-the-fly adjustments to our hike to stay safe in less than ideal weather. And both trips featured helicopter rescues of hikers who, for one reason or another, got into trouble. This isn’t an argument for knowingly carrying extra food. As any ultralighter can tell you, the more weight you carry, the more prone you are to injuries and the harder you have to work (which requires carrying more calories to cover the extra burn). One might argue that if we had been carrying less weight on these trips, instead of slowing down to let bad weather pass, we could have accelerated to beat the bad weather to the summit.

 

It’s impossible to argue a counterfactual and so where I’m left is simply wanting to continue to get better at forecasting how many calories we’ll need for a given trip. I still believe that a quantitative approach to planning food makes sense. In my upcoming trips, I will continue to experiment with that all important daily target (recognizing that it is, in fact, a moving target since the difficulty of any given hike or any given day on a hike will vary). My current thinking is that 3200 calories per day is a reasonable number for me and 2800 for Vienna. I will be trying this out on shorter trips where the consequences of getting it wrong aren’t as material as on a long trip.

 

And no matter how good we get at meal planning, that burger and beer at the end of the trail will always hit the spot in a way that no freeze-dried meal ever can!