Intermittent Fasting When Hiking and Camping: How to Fast in the Outdoors

If you know me, or if you’ve listened to the podcast in the last couple of years, you know how important intermittent fasting is to me and how much it’s changed my life. After a lifetime of being able to eat whatever I wanted and never gaining more than a couple of pounds, my thyroid decided to go hypothyroid when I was in my mid-30s. After that, my weight skyrocketed and nothing I tried worked to get my weight back down again—until I discovered keto and then intermittent fasting.

I went straight from eating three meals a day to eating one meal a day, or OMAD. Then I advanced into ADF, or alternate day fasting. My energy levels were boosted, my focus improved, and I felt great. And yes—I lost weight quickly and easily. It was like magic. I hadn’t felt that great in years.

Related reading – Cracking the Code to My Weight Loss: Keto + Intermittent Fasting

This is the point where I need to remind you not to embark on an adventure in fasting without consulting your doctor first. And don’t follow the advice of a random internet person (me) without consulting your doctor. I am not a doctor, I am not a nutritionist. I am someone who has been practicing intermittent fasting and I’m sharing my story here. Everyone’s body is different, and what works for me may or may not work for you. Above all, be safe.

Note: if there are any terms that you don’t understand in this blog post, please consult my original post on fasting: Cracking the Code to My Weight Loss: Keto + Intermittent Fasting.

Disclosure: There are affiliate links in this blog post, which means that I may earn a small commission if you click on these links and make a purchase. I am a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means to earn fees by linking to Amazon.com and affiliated sites. As an Amazon Associate, I earn from qualifying purchases. I am also a participant in other affiliate programs. 

Can you fast and hike? Can you go camping and hiking with no food?

Short answer: yes. If you’re experienced with intermittent fasting and longer fasts, and if you take precautions (carry extra water, emergency snacks, and salt). Long answer: read on for further consideration.

Personally, I would never recommend fasted hiking to someone who is new to fasting. Start slow and expand from there. It’s definitely doable, with some practice.

Intermittent Fasting When Hiking

Because intermittent fasting (IF) gave me lots of energy, that made hiking and backpacking a lot easier. And because I had lost weight, hiking and backpacking meant less weight on my feet. When I wrote my book Alone on the South Downs Way, I complained a lot about how much my feet ached. Part of this was due to the fact that I hadn’t trained enough with a bigger backpack—but to be honest, most of it was due to the excess weight I was carrying on my body. Fasting has made hiking and backpacking much, much easier.

Outdoors people love to calculate all the thousands of calories your body needs when you’re hiking—whether it’s a long day hike or a long-distance trail. Outdoors enthusiasts recommend all the snacks you’ll need throughout the day. Some people recommend eating something once an hour.

However, if your body is fat adapted and is used to burning fat for energy rather than carbs/sugar, you’ve always got integrated “snacks” in the form of body fat. Generally speaking, if you’ve been training in a fasted state, you should be able to go hiking, backpacking, or camping while practicing intermittent fasting. Again—consult your doctor before going hiking, backpacking, or camping when fasting.

Water fasting when hiking

I have not done gone hiking while on an extended fast, and I would not recommend it. My energy levels on an extended fast where I only consume water, coffee, and herbal teas are fantastic—up to and including day four. After that, I tend to feel awful. That’s why I no longer fast beyond four days. However, plenty of people get great results and feel great from extended water fasts. If that’s you, and if you’re wondering whether you can do an extended water fast when hiking, I would suggest you consult your doctor first, and then ease into it. Try hiking on day 2 of a water fast. Next time, day 3. You get the idea. Train your body to hike in a fasted state.

And always, always, carry emergency food with you. I always have one “emergency” protein bar in my backpack. I also carry extra water: if you’re experienced with fasting, you know that we get a lot of our water from food, and when we’re not eating we need more water than someone who is eating. Finally, I always have a small plastic container of what I call “pocket salt” in my backpack. I fill it up with coarse pink Himalayan salt.

Will you need to adjust your fasting protocol?

I have a complex fasting protocol based on my monthly cycle. You can read more about it in my blog post Cracking the Code to My Weight Loss: Keto + Intermittent Fasting. I won’t go into detail here, because I’m always troubleshooting and changing my plan. But I start out each cycle with a four-day fast, then I go into ADF for two weeks, then finally OMAD.

However, when I’m walking a long-distance trail, I’m a lot more flexible. I live in England, and I do most of my walking in this country. That means that when I’m staying at a B&B, breakfast is included in my stay—a very delicious full English breakfast. Since breakfast foods are my favorite foods, I eat a modified version of this. I forego the toast, cereal, and porridge. Instead, I fill up with eggs, bacon, sausage, grilled mushrooms, and grilled tomatoes. This is a high protein, high fat meal that can be low carb if you avoid all the grains.

Before fasting, I used to get a packed lunch from my B&B to eat along the trail. No more. I always carry some kind of nuts or protein bar with me, just in case, but I forego a formal lunch. I don’t even snack along the way—the nuts and protein bar are in case of emergency. Though I probably won’t have a fasting emergency after eating a full English breakfast.

I will usually—but not always—have dinner when I’m walking a long distance trail. This means that I adjust my usual fasting protocol from ADF or OMAD to 2MAD. This is mostly because I really enjoy having a pint of Guinness and a meal at the end of a long day of hiking. I probably don’t need the meal, and my body could keep “snacking” on my body fat instead.

Breakfast and dinner, however, is not the most efficient method. I do this because I cannot say no to a full English breakfast. It would probably be better to have breakfast and a late lunch, and then forego dinner—but then, I do love a post-hike Guinness. If I were hiking or backpacking in another country where the breakfasts aren’t as special, then I would probably skip breakfast and just eat lunch and/or dinner.

Do what works for you.

How to Fast in the Outdoors

Start slow. Assuming you’re already fasting, if you don’t already exercise in a fasted stay, start with that. Instead of having your meal before you exercise, exercise before your meal.

Then do a day hike while in a fasting state. Be sure to bring lots of liquids to stay hydrated—plenty of water and maybe herbal tea in a flask if it’s cold. Remember that hydration is part liquid and part salts. Bring a small container of salt and place one coarse grain of salt under your tongue once an hour. If you feel extra hungry, have some more salt. Make sure you’re getting enough magnesium and potassium in your diet.

And be sure to bring some nuts or a protein bar. It might just serve as a security blanket, but you might actually need it. There was one time when I needed my emergency protein bar—it was my very first week of fasting, and I had so much energy that I came home from my kickboxing class in the morning, took a shower, then went on a 12-mile hike. It was just too much for my system, which was still getting used to OMAD. About a mile or two before home, I felt light in the head, so I sat down on a bench and had some tea. Then I resumed my hike. I still felt unwell, so I sat down and ate my protein bar. I felt instantly better, and I was glad I had broken my fast early. This was two years ago, and it hasn’t happened since.

Once you’re experienced with doing day hikes in a fasted state, you can experiment with intermittent fasting while doing a long-distance hike. Be sure to ease yourself into the experience.

My own personal guidelines

Remember: you do you. You know how your body deals with a workout when you’re in a fasted state. Here are my own personal guidelines for intermittent fasting when hiking, backpacking, or camping:

• Liquids. I make sure I’m well hydrated (both liquids and non-sugary electrolytes). If I’m feeling unwell, I stop and have more liquids.
• Salt. If I’m still feeling unwell, I’ll have some salt. I might have a few grains of course salt at once and suck on them as I rest.
• Food. If I’m still not feeling well, then I have my emergency nuts or protein bar.

Intermittent Fasting When Backpacking and Camping

It can be tricky to pack for a keto-friendly backpacking or camping trip when you’re planning to practice intermittent fasting.  Traditional camping foods are pretty lightweight: porridge, granola bars, pasta. They’re also very carby. In my experience, a high-carb diet makes fasting incredibly difficult. It will also kick you out of ketosis, meaning that your body will no longer be able to rely on your body fat for “snacks.” This could lead to carb crashes while hiking.

Keto-friendly backpacking and camping foods tend to be heavier. Think: cheese, meats, and nut butter. This will add considerable weight to your pack. However, you’ll be eating fewer meals than the average hiker, so rather than eating three meals a day plus snacks, you’ll probably be eating just one or two meals a day.

Here’s a list of some keto-friendly foods to take when backpacking and camping. I know that not everyone who does intermittent fasting also does keto, but in my experience, eating a high-fat, low-carb diet makes fasting much, much easier. This is especially important when you’re practicing intermittent fasting while hiking, backpacking, or camping. You want your body to stay fat-adapted so you don’t end up with a carb crash halfway through your adventure.

The good thing is that these foods don’t require cooking, which means you can lighten your load even more by leaving your cooking stove at home! Of course, you may not want to forego your morning coffee or evening tea, but it is an option with these types of foods.

• Cured meats. Hard sausages and/or chorizo, beef jerky (either get biltong—which is not as sugary—or find some that’s sugar-free), and salami. Pork rinds are a favorite among keto fans, but I think they’re disgusting. I have also cooked up a bunch of bacon and brought it with me in a baggie for a two-day camping trip.
• Eggs. Hard-boiled eggs won’t last long unrefrigerated (a quick internet search told me just two hours, but I think that’s a bit exaggerated) but you might want to bring a few for your first day of camping or hiking. You could chop them up and add a few packets of mayonnaise to make a rustic egg salad. Otherwise, stick to powdered eggs.
• Fish. In some countries, you can get tuna in packets, which are more lightweight than cans. If you’re not particular about ultralight travel, you might consider cans of tuna, salmon, and/or sardines, but you’ll be stuck packing out the empty cans. In the UK, you can find small tins of mackerel and other fish (again, you’ll have to carry out the tins).
• Greens and veggies. I always break my fast with Athletic Greens, which is a powder you can portion out into a baggie, or you can carry their individual packets. Fresh veggies are not necessarily backpacking-friendly because they can get crushed in your pack. Avocados are heavy, but they’ll add healthy fats to your camping diet. You could also bring a small baggie of olives for the first couple of days. If you’ve got the room in your pack, maybe add some bell peppers to the top, as they won’t crush quite as easily as softer veggies.
• Hard cheeses. Such as parmesan, grana padano, asiago, and romano. I’ve also found that gouda and emmental, while not hard cheeses, will hold up for 2-3 days on a backpacking trip.
• Nuts and nut butters. Unfortunately, many of the good-quality nut butters come packed in glass jars rather than plastic. Consider re-packing your nut butters in plastic jars to lighten your load. Peanut butter can sometimes be carby, so I’ve seen people suggest removing a bit of peanut butter from the jar and adding a stick of butter to “dilute” the carbs and add more fat. Nuts are a great source of fat, and I’ve read that macadamia nuts pack the most calories, protein, and fat by weight.
• Porridge. While oats are very carby, you can make a cold soak porridge out of chia seeds, nuts, pepitas, sunflower seeds, and unsweetened shredded coconut. Add protein powder and powdered milk or cream, and mix with water to soak.
• Powders. Protein powder is a great source of lightweight protein, and in the US you can find MCT oil, coconut oil, and other healthy fats in powder form. Also, powdered eggs. Electrolytes are another thing you can bring in powder form. And, as I mentioned above, Athletic Greens.
• Protein bars. I love Carb Killa bars, though some people don’t consider them to be keto-friendly. I’m not strict with keto, so I do find them to be IF-friendly. Take whichever low-carb protein bars you prefer. Or make your own! If you’re tempted to bring keto fat bombs, remember that coconut oil is often a key ingredient, and this can melt in hot weather.
• Trail mix. Make your own with a variety of nuts, pepitas, sunflower seeds, and unsweetened shredded coconut. If you want to add dried fruit, remember that berries are a low-sugar fruit. Add unsweetened dried cranberries, blueberries, or strawberries instead of raisins, which are high in sugar. Unfortunately, as in the photo below, most store-bought trail mixes are full of raisins. You can also add keto-friendly, sugar-free dark chocolate chunks.

If I’m car camping—or staying in one place for a few days—I’ll put together small food boxes like these square Sistema boxes with the following foods: hard sausage, salami, cheese, cherry tomatoes, and olives. I break my fast with Athletic Greens, then I eat one of my food boxes, and finally I follow it up with a protein bar.

Can you through-hike while intermittent fasting?

I’ve practiced intermittent fasting on long-distance hikes of up to 8-9 days. Through-hiking a longer trail like the Camino de Santiago, the Scottish National Trail, or one of the super-long US trails like the Pacific Crest Trail is a whole different story. You will need plenty of food to fuel your body. Even if you start out with excess fat stored on your body, this will decrease over time as you progress along the trail, meaning that your internal “snacks” will be depleted and you won’t have the same amount of reserves as when you started out.

This also applies if you’re doing a shorter hike but you’re putting in very long days.

Remember that “breakfast is the most important meal of the day” is BS. If you’ve been fasting for any amount of time, you know this. Also, fasting gives you energy. It will also save time if you skip breakfast in the morning—you can go straight to packing up your tent and getting on the trail.

Ultimately, you need to find what works for you. Start with shorter trips and see what is best for your body. This blog post is not meant to give you a definitive plan to intermittent fasting while hiking, backpacking, and camping. It’s meant to give you ideas that you can adapt to your own personal protocol. Experiment to find what works for you. Again, always consult your doctor.

Bring extra clothing

Remember that you’re at a greater risk of hypothermia when you’re fasting. Have you ever noticed that you get cold when fasting, even when you’re sitting at home? When engaging in outdoor adventures while fasted, be sure to bring extra clothing: gloves, hat, layers.

There was one time when I went camping in mid-March, and the temperatures went down to freezing. I was only eating breakfast and lunch, and by the time I was ready for bed, I was so cold I was shivering. My sleeping bag wasn’t good enough for those weather conditions. Shivering is an early sign of hypothermia, and I should have just had a snack to warm my body up. Instead, I added more layers of clothing, as well as my emergency silver blanket. In retrospect, this was dangerous, and I should have broken my fast. So be aware of your body temperature, and always have emergency snacks with you—and be willing to eat them!

Always plan for emergencies

Be safe. Always have extra food with you when you go in the outdoors, no matter whether you’re fasting or not. That’s just basic safety.

Eating food can also keep you warm if you’re in a survival situation, and if you’re cold it’s good to have some food. Stay safe, and don’t take risks. Remember that shivering can burn up to 400 calories per hour, so if you’re in an emergency situation, forget about fasting, and just eat. If you’re cold, eat. Be safe.

Related reading

Read about my two adventures along England’s most popular National Trail in this second edition of my book Alone on the South Downs Way. This book contains all the blisters, sweat, and tears from my first life-changing journey—and all the joy, presence, and magic of the second one.

More than just a walking travelogue or memoirs of a walking holiday, this book contains my reflections on walking the trail, including lessons learned and practical information to help you plan your hiking adventure. It includes a suggested packing list, gear recommendations, and other useful tips, such as when to walk the trail, where to stay, and how much you’ll need to budget.

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