Eat, Dammit: 5 Strategies to Optimize Your Caloric Intake During a Thru-Hike

When I finished my thru-hike and sat down to write articles that doled out the hard-earned wisdom of a past thru-hiker, I decided I was not going to pass on any advice pertaining to subjects I didn’t feel I had succeeded in. Better to leave those subjects to the pros. Leave the gear lists to the people that debate every quarter of an ounce, not to the person who at one point realized she was carrying four different Chapsticks. So I sat in front of my computer, ready and eager to impart knowledge to a new generation of thru-hikers (whether they wanted it or not), and realized this ruled out basically every subject I could possibly talk about.

No one succeeds at all aspects of thru-hiking in their first thru-hike, regardless of how many of these handy articles you read. So instead I decided to try a new tactic. What I should do is talk about subjects I failed at the most. Those, I knew inside and out. I had learned (eventually) how to succeed at them, but I also intimately knew the things you should NOT do.

The most obvious of these subjects: eating.

Eating. It seems so simple. But while you’re thru-hiking it can be very challenging. I spent the vast majority of Massachusetts convinced I had Lyme disease. I had a pounding headache, was dizzy, and my arms and legs felt like noodles. My sweat felt like ice on me, even though temps were mostly in the high 80s. I couldn’t focus long enough to do basic math in my head. And I was so, so, so tired. Every step felt like the most difficult step I had taken in my thru-hike so far.

Turns out these symptoms are not just part of the smorgasbord of things that go wrong when you get Lyme. I was hungry. Not just hungry, but calorie deficient. The calories I was consuming weren’t enough to cover the amount I was burning walking 10 to 12 hours a day.

The Basics

It’s estimated that you need to eat roughly 5500 calories a day while thru-hiking (although a whole host of variables need to be considered, including your age, gender, etc). That’s a lot of food. I had never actually considered 5500 calories worth of food before. It’s a lot. And it’s very heavy. And for all my brainstorming, I never really came up with a way to take it with me that wasn’t carrying it, which is important because the heavier your pack is, the more calories you are going to burn. When you’re at the grocery store, do you ever figure out how much something costs per ounce to decide what gives you the best value? Do the same thing with your backpacking foods, except with calories per ounce.  Other than that, I don’t have a lot of advice in the way of what to eat, since that’s something that will vary wildly from person to person based on taste and also oh-my-god-I’ve-eaten-pop-tarts-for-two-straight-months-and-I-will-never-look-at-a-pop-tart-again syndrome, which is also an inevitable part of thru-hiking. I do have a lot of advice in how to eat, since this is what I ended up changing the most to right the ship.

Actually count calories

440 calories

When you’re resupplying, actually look at the labels and add up the calories of whatever you plan to eat per day. I NEVER did this, even knowing I was supposed to get upwards of 5000. I just grabbed a crap-ton (that’s a scientific measurement) of food and assumed I was fine. In Massachusetts, I actually added up the calories I was eating per day and found it was closer to 3000. You are going to be hungry regardless of how many calories you’re eating, so you can’t use that as a guide for if you’re eating enough. Get a good idea of what 5000 actually looks like early on.

Eat frequently

And on the go

Breakfast, lunch and dinner? Banish that concept from your mind. A better eating schedule is: breakfast, second breakfast, lunch, second lunch, afternoon snack, dinner. By the end I just ate something every hour and did away with the idea of “meals” entirely. To do this, you have to master the walk and eat. Set aside your snacks for the day in easy to reach compartments and pick your spots (i.e. don’t eat when it’s really rocky or uphill). If you only eat when you stop, then you won’t eat enough on days you’re in a groove and don’t feel like stopping.

Eat even if you’re not hungry

I know, I know! Everyone always talks about hiker hunger, so you probably assume that you’ll always be hungry. But I got the flu in the Smokies and a cold in Northern PA, both of which really suppressed my appetite. I hiked through both of them, barely eating anything for the duration of each, only to crash and burn badly once I started feeling better. You can’t escape suffering the consequences of not eating while hiking for that long, even if your body isn’t telling you need food. Either force yourself to eat, or better yet, accept that you’re sick and take a couple days off, a revolutionary concept I never considered.

As an aside: While I had that cold in PA, a friend and I stopped at Dunkin’ Donuts one morning. He asked if I wanted to split a dozen donuts, an opportunity I normally would have jumped at. But my stomach turned at the idea and I ended up buying just one and nibbling at it. For the next two weeks I spent every hiking moment (and I mean that literally) thinking about how badly I wanted one of those donuts and what a complete IDIOT I was for turning it down.

Never go to bed without eating

During the summer when the days were longest, I got in the habit of stopping around 5 or 6pm for dinner and then packing up and continuing on until the sun started to set. Then I’d set up my tent and immediately pass out in it. It wasn’t until way later I realized how bad this is for you. Your body needs something after exerting energy, even it’s just a Clif bar between setting up your tent and going to sleep. Burning its stores and then not eating for another 8 hours is tantamount to torture.

Resupply often

The second easiest way to boost calories while keeping your pack weight down is to resupply as frequently as possible. 3 days of food weighs a lot less than five days of food, which then gives you the luxury of carrying more food per day. At the beginning, I tried to stretch out my stints in town as long as possible in an effort to save money. But I also never considered that a stop in town didn’t have to include all the stops, i.e. resupply, laundry, shower, night in a hostel, dinner and breakfast, etc. At the end I would alternate: if one stop in town was overnight and included the whole kit and caboodle, the next would be a mid-day stop for lunch and resupply before continuing on. This also meant I got more meals in town, which is THE easiest way to boost calories (and morale).

In conclusion

There is an inevitable amount of trial and error in a thru-hike, especially your first. Making a mistake to learn to never make that mistake again is all part of it and the biggest secret to being a successful thru-hiker is surviving lessons taught the hard way. THAT SAID: Trust me when I say you’d rather not learn about calorie deficiency the hard way. Count your calories. Eat often. Consume all the ice cream.


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Comments 8

  • Ruth Morley : Mar 17th

    I always, always enjoy your posts. Thanks for this one!

  • DD : Mar 18th

    Love this. I struggle with eating on the trail. happy trails!

  • Roy : Mar 20th

    Excellent post – thanks!

  • TBR : Mar 20th

    Great advice.

    I couldn’t carry enough to eat 5,000 calories a day, so … I lost a lot of weight, and I was only on AT for a little over two months (it was a section hike).

    Finished trim and fit!

    But thru-hikers sometimes finish in a malnourished state, so … as, Mother Becky advises, clean your plate.

  • John Cressey : Mar 23rd

    Thank you!

  • FM : Mar 25th

    Hi, Becky.

    Eating can be a chore. You can still eat three meals and brandish a few quick in between snacks and have enough energy for your hike. The big secret? Sugar drinks like Gatorade. If you eat three 1000 calorie meals and have 6 mid-meal snacks like Belvita bars, you have 4100 calories there. You just need 900 more calories, and you can get that from 4.5 quarts of drinks. These drinks are vital for the following reason:

    You ‘bonked’. You killed your muscle sugar stores–oh, what a feeling, eh? :D. All the high calorie density fat in the world won’t fix that. It’s not only important that you get enough calories, but you also want to make sure those calories have plenty of carbs to replace muscle sugar.

    Lesson learned from the hummingbird:

    Sugar is not bad for you when it is actually needed and burned for energy (not stored as fat) unless you are onset diabetic of course, then it’s just too late. Sugar may be less calorie dense than fat, but it’s what you need to overcome that ‘bonked’ feeling. Converting fat to useful energy is slow, so you are literally lugging your engine, hence the power drain. By drinking sugar drinks (especially if it has salt in it for cramps) you head off muscle glycogen depletion and avoid the bonk. I try to get my carbs up to 55-60% of total calories. I also try to keep breathing at a comfortable rate. Running or walking too fast can change the ratio of carbs to fat use and deplete your glycogen stores earlier.

    It’s the same as starting out each day after hiking 1-2 minutes. You start noticing this miserable feeling and start asking yourself “why am I doing this?”. That’s because your body hasn’t adjusted to the rate of energy you are demanding yet. You burn off the 1-2 minutes of quick energy everyone has then it takes another 2-3 minutes for your energy system to catch up with your pace (hence what a warm up helps you avoid). Slowing down in the 2-4 minute window helps avoid this, too. I now slow down in the 1:30 to 4 minute window so the feeling doesn’t demotivate my run.

    Anything over 120 grams of protein per day in a very active day gets burned. Protein repairs tissue and can be used for energy. Better for repair, not energy. You can smell ammonia when you are burning it for fuel. Ew! Nothing like ammonia blending in with that raspy hiker smell. So consider 120g for repair and not part of your caloric intake. Subtract out 480 calories.

    For a male of 6ft height, 160 lbs trail dry weight, and carrying 20-32 lbs, figure 100 calories burned per mile. For 10 hours at 2 mph average that’s 20 miles and 2000 calories. Basal metabolic is about 1500 calories (what I need just to exist). Figure 6 hours of wakeful activity at 100 calories an hour–600 cals. So that’s 4100 cals. Then you need 10% to digest all that–so 4100/0.9= and you have about 4555. Add 480 cals of protein not used for energy and you have 5035 cals total. And that is where the often quoted 5000 cals per day of AT hiking comes from.

    Of the 4555, I want 60% carbs and 40% fat. By the time you have your trail legs, you are probably burning 70% fat to 30% sugar at a comfortable pace, not 50/50 like when you started out. That’s why it comes off so fast on the AT diet (eat anything and still lose weight! 😀 ) So I want 2733 cals of carbs and 1822 cals fat for a 20 mile day.

    Don’t let people convince you fat packs better. It does–it’s lighter, but we don’t want to tempt that bonk, now do we? Only carbs can fix a bonk.

    60% carbs (54.3% of total) is necessary for good testosterone production which keeps you motivated to hike. So is animal fat in that regard. Do not fear the butter and bacon!

    Remember, nothing is bad for you when you are needing and using it (except eating peanuts when you are allergic to them, and that’s the only exception, haha). Our culture is latent with incomplete ideas that sugar, salt and fat are ‘bad for you’. It’s only because we tend to eat for pleasure rather than need. We don’t exercise or eat correctly according to need. On the trail, its actually beneficial and necessary for preventing the bonk, avoiding headaches and weakness from dehydration and for building motivation/stamina.

    Hydration was possibly an issue for you. We tend to forget to drink enough water when we hike. “Too much water is bad for you” is also an idea that isn’t complete. Maintaining blood volume with proper mineral balance is. If your blood volume drops, your heart has to beat harder to distribute it (keep track of your rest pulse). Intra-cellular activity becomes inefficient with a reduced pool size with everything bumping into each other, especially when supplying energy, so we get tired easily and feel crappy.

    Enter the magical elixer!!!! Water. (Tadaaah!) You must have a corresponding amount of salt/minerals to replace what is lost. Even Gatorade doesn’t have enough. The real sport drink has more salt in it. The other is not designed for football games. They appeal to a larger market. If you drink too much water and don’t replace the minerals, you can literally drop dead from water poisoning, even in the space of a 2-3 hour marathon.

    I’ve run trail all day on the AT with a pack for an accumulated 16 hours in 75-80 degree heat many times. Let me tell you, 10 quarts a day (for me) is not enough under those conditions. I’ve had cramps like a…well, I try to avoid that kind of language now, but you get my drift. 1/2 to 1 liter per hour of activity depending on temperature and the intensity of activity is often recommended, but it has to be balanced with proper mineral intake and monitoring of your body’s tell-tale gauges.

    I pack chocolate powder milk to help the drinking be more pleasant. Nothing like chugging that down and having the rich potassium content throw a delicate sodium potassium balance out of whack, especially when sodium is already low. Let me tell you, the cramps in your thighs will make you eat salt like it’s a candy bar.

    I’ve also bonked several times on the path to learning how necessary carbs are and in what amounts.

    Pain is the Great Teacher. And we are of those disciples who have gotten seriously schooled by it. Perhaps me more than others.

    I’m not a doctor, so save a few grains of your rehydration salt for my advice. This on the other hand is what works well for me. I dunno, all of you reading this might have average human bodies in general good health, too. Unless you are 10% different from me–then you might be chimps. ; )


    • FM : Apr 5th

      One correction on calorie calculation–neglected 10% digestive expenditure for the protein. Add 48 more calories.

    • FM : Jul 3rd

      I’d like to also add that if one develops a “base” for endurance training, a greater proportion of fat handles low speed energy requirements compared to carbs. In that case, one can probably improve pack weight by placing more calories into higher density fat. Whereas I suggested above 60% carbs and 40% fat, a highly trained individual might be able to reverse that to 40% carbs and 60% fat. (% of total calories less protein calories, which should be used for body repair and amino acid resupply for the brain’s neurotransmitters only.)

      I’d say most hikers develop this kind of fitness early into their hike. It takes about 42 hours of training to build a base (6 weeks of low speed exercise @ an hour a day). Thru-hikers can build their base in a week or two. Better to hit the trail running though, I always say. You can tell when your base is built by your newfound craving for fat.


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