How to Fuel Your Trail Running

Molly Hurford
by Molly Hurford
Share it:
How to Fuel Your Trail Running

If you’re new to trail running — or even if you’ve been doing it for years — the one piece of the puzzle that often gets overlooked is the nutrition component. Because trail running is a more intense, full-body workout, the way you fuel your road run isn’t the same as how you should fuel on the trail.

There are plenty of similarities, of course — running is still running, after all. But your core and upper body become more engaged during trail running, and the activity requires significantly more concentration as you leap over roots and rocks, so it’s not as easy to eat on the run, explains Ted Munson, performance nutritionist at Science in Sport.

But, before we actually hit the trail, let’s dive into what the best trail runners and the experts in sports nutrition are suggesting pre-run.


You should prepare for each hard or long trail run the same way you prep for a race, says Munson. This way, you’re mimicking race day and learning what works best for you. Munson recommends eating a balanced meal with an emphasis on complex and simple carbohydrates so when you take off on the trail, your muscles’ glycogen stores are topped off and you’ll be adequately fueled from the very first step.

“Just focus on regular foods,” says ultrarunner and coach Jason Koop. “If anything, take out some of the more fiber-rich foods on the day before a race.” Neither Koop nor Munson think carb-loading by crushing three bowls of pasta is a good idea. You should have some carbs, but don’t go crazy.

I used to carb load, but the more I researched and learned about it, the more it came to light that carb loading is something you have to do over the process of at least a week,” says obstacle course racer Lindsay Webster. “Eating a plate of pasta the night before your race isn’t really going to have any effect, and carb-loading is typically not necessary unless you’re competing in an ultra endurance event.”

Last piece of pre-run advice? Focus on the 24 hours before your race. Dinner the night before should be your last big (but not too big) meal, rather than trying to eat a massive breakfast. To be blunt, it’ll likely just end up in the port-a-potty or a hole on the trail. Keep breakfast simple and not too big. (And drink coffee if you know it’ll speed up your bowels. That pre-run ‘movement’ is crucial.)



Before you start panicking and packing a bunch of snacks for your five-miler in the woods … pause. For runs less than an hour, Munson says you’re better off skipping the mid-run fuel — your focus should be on fueling up pre-run. Your muscles should have enough glycogen to get you through a short run.


Koop and Munson both agree that when you are going long, it’s important to start fueling early, rather than waiting until you feel the bonk setting in. “For longer runs and races, it’s key to start eating early, somewhere around 60–90 minutes into the activity,” says Koop .


A shorter practice run is a good chance to experiment with new foods. You definitely don’t want to try something new during a race or really long run — there’s no room for error. The key is to figure out what works for you and your stomach. Koop swears by his secret rice balls, while Webster prefers gels for her energy source.


Forget fat-adaptation and a ketogenic diet if you’re planning to do any kind of serious endurance running. “Carbohydrates are king during long runs and races,” says Koop. “Fat and protein can be used for satiation, but they are not particularly useful for energy.”

You can opt for energy gels, blocks or bars or, if your stomach handles real food better, try dried fruit, pretzels or the homemade rice balls mentioned above.


Some people don’t respond well to calories in their hydration source, so you also want to practice what you drink. A high-calorie energy drink can sometimes act as both hydration and fuel, but it might not be the best bet for your tummy.

When you’re on a particularly gnarly trail or don’t want to carry too many items, Munson says it’s OK to rely on liquid calories for both nutrition and hydration. But for most people, taking in food and water separately is the preferred method of fueling.

“For longer runs, it’s important to separate your solid calories from your hydration, as the temperature conditions can vary and force you to drink more or less accordingly,” says Koop. “[Separating your hydration and nutrition] will allow you to independently regulate your fluid intake and your caloric intake. A hydration drink that is lower in calories and contains sodium will be preferable to a high-calorie drink.”

This is the part most athletes struggle with, especially those new to trail running and uncomfortable with the terrain. There’s no need to worry if you take in more water and more calories when you combine the two.


Unfortunately, the thing that provides your hydration and food can also hurt you. An improperly fitting run pack can make the miles miserable, as can a too tight or too bouncy fuel belt. If you’re planning to race wearing any kind of food- or water-carrying contraption, practice with it before race day. The same goes for long runs: Use shorter runs to practice with the pack, so you’re used to how it feels.

“Use it in training and load it up with the things you need on race day,” says Koop. “Even if you don’t need it for training that particular day, it’s important to load the pack up to see how it rides.”

Webster adds that for those who don’t like the more common pack and belt options, there are vests available that fit bottles in the front. “I’ve found I’m much more balanced wearing my water on the front, instead of having it slosh around on my back,” she explains.


There’s no one right answer to the question of how much to drink it depends how hard you’re running and other external factors, like the weather. “If you’re racing, you’ll need to drink more than if you’re out for an easy training run,” says Webster. “I’d try to drink at least 500ml every hour. Consistent urination is always a good sign; if three hours have gone by and you haven’t had to pee, drink up! It’s also harder to hydrate in winter, because you won’t feel as thirsty in the cold, so be sure to remind yourself to drink.”


Webster says that by the end of a long race, she’ll eat everything from Pringles to brownies. Ultrarunner Eric Batty seconds the chips and adds, “If it is going to be a really long day, I will add in some sort of Pringles and beef jerky for the sodium and it’s usually what I crave when going over 1012 hours.” So if you know you prefer salty to sweet, pack something that will excite your tastebuds.


The last piece of advice may save your run, your mood, your friend or your life. If you’re heading deep into the wilderness, always carry a spare gel or two, plus water-purifying supplies, especially on training days when you might be alone in the woods. Batty always packs Aquatabs, which can make creek or lake water drinkable, and Koop carries a portable filter that fits easily in his pack.

Under Armour has teamed up with POWDR Resorts to create the UA Mountain Running Series, an experience of a lifetime for trail running enthusiasts at the most iconic and beautiful mountain resorts in the United States. The race course locations will feature diverse climates, seven different distances and varying elevations built to push athletes at every level to their personal limits. Register now for a summer you won’t soon forget.

About the Author

Molly Hurford
Molly Hurford

Molly is an outdoor adventurer and professional nomad obsessed with all things running, nutrition, cycling and movement-related. When not outside, she’s writing and podcasting about being outside, training and health. You can follow along with her adventures on Instagram at @mollyjhurford.


Never Miss a Post!

Turn on MapMyRun desktop notifications and stay up to date on the latest running advice.


Click the 'Allow' Button Above


You're all set.

You’re taking control of your fitness and wellness journey, so take control of your data, too. Learn more about your rights and options. Or click here to opt-out of certain cookies.