Thru-Hiking Nutrition, Part 2: Eating for Health

By Laura Lancaster

I could hardly contain my surprise at seeing my dad. After two months and 1,000 miles on the PCT, he was tan, happy, and easily 20 pounds lighter than when he started out. A fact that he gleefully demonstrated by showing us how far he had to cinch his belt to keep his shorts intact during a quick visit home before getting back on the trail.

thru hiking

But he was struggling to keep his energy levels up, despite eating about 4,000 calories a day and following Dr. Braaten’s advice to end each day with a significant snack. And in addition to his late afternoon fatigue, he was still losing weight. So what was going on? He was out of the desert, so dehydration likely wasn’t the issue. I went back to my notes from PCT trail angel and long-distance hiking nutrition expert Dr. Brenda Braaten to see what she had to say on the matter.

“If you’re running at a deficit of calories, you’re going to see the skeletal wasting, but what you aren’t seeing is the loss of digestive enzymes,” Dr. Braaten had told me. Digestive enzymes are essential for accessing the nutritional properties of the food we eat. Without them, food will wash out of the body without releasing important nutrients, leaving you malnourished, even though you’re meeting or exceeding your daily caloric needs.

Digestive enzymes can be lost in a number of ways, from stress to a poor diet, but the one that is most likely to affect thru-hikers is simple disuse. What hikers eat when they are on-trail is often so limited and monotone, and the body is so distressed with all of the demands being placed on it, that their digestive tracts will simply stop putting energy into producing enzymes for certain foods. For example, if on-trail you are eating a carbohydrate-rich diet your body may start to produce fewer digestive enzymes for fats and proteins. Then when you do finally get to a trail town with great milkshakes, or that legendary monster burger, eating large quantities of these foods can overload your digestive tract.

eating at diner during thru hike

So that diarrhea that so many hikers experience might not always have an external cause, like poorly cooked food, or bad water. They could be the result of digestive enzyme deficiency. And if your digestive enzymes are flagging, it’s best to take steps to replenish them. While a balanced diet is the best strategy for replenishing digestive enzymes, one way that hikers can supplement these efforts is by purchasing a probiotic. These are live cultures that contain bacteria and yeasts that help to promote a healthy digestive track. Hikers should be able to find these in some of the larger towns along the trail, and those that are sending boxes ahead should consider adding shelf-stable probiotics with a high bacteria count. Before he headed back out on the trail, my dad, in addition to eating healthily at home, purchased a box of probiotics and redistributed them into his resupply boxes. Hopefully they will help to stem his weight loss and he can finish his hike.

But even if you aren’t experiencing weight loss or low energy, there are other reasons to be concerned with efficient nutrient absorption on the trail.

Eat your vitamins                              

Keeping up a healthy supply of vitamins and minerals is such a challenge that many thru-hikers give it up as a lost cause before they even start their hike. And no wonder: while occasionally hikers are able to resupply at a standard grocery store, most trail towns are too remote to offer much selection.

thru hiking

More often, hikers resupply out of a gas station convenience store or bodega, with bruised bananas and wilted lettuce, and shelves picked over by other thru-hikers. Those sending themselves food packaged at home won’t fare much better. Resupply boxes are typically sent out two to three weeks in advance to remote locations, and along the way are exposed to temperature extremes, all kinds of weather, and, occasionally, rodents. Whatever is packed in those boxes needs to be durable, and with a long shelf life. Fresh fruits and vegetables are out.

For some hikers, this is treated as good news: if it’s going to be virtually impossible to eat right anyway, might as well enjoy some McDonalds.

thru hiking sign to mcdonalds

But if you’re interested in keeping your health up for the duration of a thru-hike, it can pose a serious challenge.

Some hikers try to ensure they’re getting a healthy dose of vitamins and minerals in their system by taking along dried fruits and vegetables. Unfortunately, this strategy may only be partially effective. “Hikers probably aren’t getting the nutrients that they are expecting,” said Dr. Braaten, “Studies have shown that dried fruit contains as few as 5% of the vitamins in fresh fruit.” And even when the drying process is efficient at keeping vitamins and minerals locked in, excessive exposure to heat and air in storage may deplete them in transit to their destination. This is particularly true of water soluble vitamins, including Vitamin C and the B vitamins.

thru hiking meal

In addition to being lost during the drying process, water soluble vitamins are also not stored in the body long-term. As a result, many hikers will end up Vitamin C deficient during some portion of their thru-hike. This can negatively impact hikers’ health in multiple ways, from compromising their immune system to an increase in nosebleeds. Vitamin C also plays an important role in producing our body’s connectivity tissue. Long-term vitamin C deficiency may compromise the integrity of the body’s connectivity tissue, especially in high-stress areas. Dr. Braaten believes this may be a contributing cause to the foot swell that so many hikers experience.

To combat this problem, some hikers will choose to carry a multivitamin with them during their hike. This may have limited benefit. Because of the sheer volume of a thru-hiker’s diet (and the aforementioned digestion challenges) too often these multivitamins pass straight through the body’s digestive tract without releasing their nutrients. To combat this issue, Dr. Braaten suggests chewing on your multivitamin first or, even better, choosing a fortified drink mix (like Emergen-C), which your body will be able to more easily extract nutrients from.

And, of course, whenever fresh fruits and vegetables are available, don’t pass them up.

stopping to eat on thru hike

Store up in town

While the body is able to readily absorb vitamins from lightweight drink mixes, it is not nearly as efficient at absorbing minerals from supplements. The good news is that minerals, unlike vitamins, are stored by your body, so it’s possible to avoid negative outcomes by eating healthy, both before your thru-hike and at trail towns.

eating in town while on thru hike

That being said, there are a few minerals that hikers should take steps to ensure they are getting enough of, including iron and calcium.

Digestive enzyme depletion is one cause of exhaustion during a thru-hike, but another likely culprit (particularly among women) is iron deficiency. As your body ramps up during a thru-hike, its oxygen needs go up and up, resulting in an increase in the production of hemoglobin (the oxygen carrying molecule in the body). Iron is essential for producing hemoglobin, and without it, your body will have trouble getting the supply of oxygen it needs to stay in tiptop hiking shape. Some hikers even become anemic during their thru-hike.

Calcium deficiency may likewise be responsible for a range of common hiking problems, including cramping and charley horses. Plan ahead to prevent calcium deficiency from affecting your hike by incorporating calcium-rich foods into your diet, such as packing dehydrated milk products into your resupply boxes in advance or purchasing a hard cheese at your resupply stop to pack out to the trail. Also consider cutting sulfite-rich foods, such as certain types of dried fruit, from your diet, as these can promote calcium loss beyond what you might normally experience.

Read more about Dr. Braaten’s research here.

Hiker-Trash Salad

At Big Bear Lake during our 2014 PCT thru-hike, my husband and I ran into a couple of hiker friends who were just starting in on a bag of spinach from the local grocery store. I was far enough into the thru-hiker mindset at this juncture that I jumped at their offer to share, blissfully unaware of the optics of four grimy hikers be eating a bag of spinach in the middle of a parking lot. That first taste was heavenly, some of the first fresh vegetables we’d had in weeks, and at each trail town after that we tried to buy a bag of spinach to share.

The below recipe offers some ideas on how to improve your vitamin and mineral absorption on the trail with the likes of what you can find in trails towns like Sierra City or Seiad Valley. Leave out ingredients you can’t find, and add in others that sound appealing. Just like your hike, Hiker-Trash Salad isn’t something that you’ll be able to predict in advance, but you can trust that the trail, as it always does, will provide what you need to make it happen.


  • 1 Bag of Baby Spinach (B Vitamins, Iron, Vitamin A) or Kale (Vitamin A and C, Calcium)
  • 1 Can of Garbanzo Beans, drained (B Vitamins, Iron)
  • 1 Can of Tuna, Packed in Oil (B Vitamins, Iron)
  • ½ Cup of Shredded Carrots (Vitamin A)
  • 1 Cup of Shredded Cheese (Calcium)
  • 1 Cup Cherry Tomatoes, Halved (Vitamin A and C)
  • 1 Cup Broccoli Florets (Vitamin C)
  • 1 Cup Salad Dressing of Your Choice (if none is available, try adding olive oil or mayo)


  1. Wash your hands thoroughly with soap and water. Apply Purrell to your hands and rub until dry.
  2. Open up the bag of spinach
  3. Add all ingredients to the bag, except the salad dressing
  4. Wash your hands again
  5. Using your now-clean hands, thoroughly mix the ingredients together in the bag
  6. Pour on salad dressing to taste

Grab a plastic fork, your titanium spoon, or any other utensil that fits the bill, and enjoy!

Read: Nutrition for Thru-Hikers Part 1: Food for Fuel

Laura Lancaster started backpacking at the age of 12 and hasn’t let up since. Currently a freelance writer and editor living in Seattle, she thru-hiked the Pacific Crest Trail in 2014 and the Wonderland Trail in 2015. Laura has been published in Backpacker, Survivor’s Edge magazine, and American Survival Guide. You can see more of her work at