Fuel for the Journey

Words By: Eric Carter

Photos By: Guy Fattal

In the build-up to Eliud Kipchoge’s two-hour marathon attempt, sports scientists in Sweden worked hard to develop a new sports drink system that would be the fuel to propel him across the finish line. Sport scientists tweaked the delivery system, the nutrient content, and the timing. Unfortunately, not every trail or mountain athlete has access to this level of sport science. In fact, it’s far easier to follow the same general principles that elite athletes use in their fuelling while not getting bogged down in the fine details. I use the following principles while training and competing in events ranging from 30min vertical kilometer runs, to 1.5hr skimo races, to 18-hour ultra-efforts in the mountains. By keeping my strategy simple, it’s easy to stick to it and easy to adapt when things go wrong.


It’s easy to get caught up in precisely counting calories and nutrients, and then discouraged when you get off track. Instead, focus on the very basic number of total calories per hour. Target a consumption of 100-200 calories per hour of exercise. If you’re within this range, you’re in pretty good shape. To get this, here’s a rough estimate of what you could consume:

0.5 – 1.0 L of sports drink

0.5 – 1 energy bar or package of chews

1-2 energy gel packets

While we’re on the topic of calories, it’s important to think about where you get your calories and tweak depending on your activity level. Simply put, carbohydrates are performance enhancing. Simple sugars give quick bursts of energy while starchy carbohydrates and fat give longer lasting energy. If you omit carbohydrates or fat altogether from your fuelling strategy, you’re giving up some of your performance potential. A basic strategy is:

During higher intensity exercise (especially racing in the 30-120min range) increase simple sugar intake (sports drink, bars, gels).

During longer and lower intensity activity (mountain adventures, ultra-races, hiking), use fewer simple sugars and a more balanced intake of carbohydrates, saturated and unsaturated fats (like nuts, fish, etc..), and protein.\

Finally, don’t forget about fluid calories. Sports drink can be easier to ingest with an upset stomach and assists with hydration!


It’s a common misconception that train without fuelling (fasted) makes it easier for you to perform because you’re used to low fuel levels. However, while you can make it through that two-hour easy run without fuelling no-problem, you absolutely must fuel to run that 50km ultra at race pace. All of the sudden, when you are forced to eat in order to finish that effort, your stomach – used to training on empty – becomes overwhelmed. A well-trained athlete will train their stomach just like they do their muscles. Make sure to fuel in training just like you expect to during a performance or long effort. If you’re training session is more than 1.5 hours, follow the fuel recommendations above!

Similarly, use a variety of fuel and don’t depend purely on sports drinks/gels/bars. As mentioned above, the longer the event, the more balanced the intake must be. It’s also important that the food you plan to use is palatable after a sustained effort. Experiment with these options in training and then be prepared in your event. For long days in the mountains skiing, climbing, and even running, I bring a full supply of energy food and then if I am out for more than one meal’s worth of time (say I’ll miss a breakfast and lunch), I bring at least one real food option like a burrito, sandwich, or slice of pizza. These break up the monotony of energy food and give a feeling of fullness, something that is psychologically important on long efforts. Make sure to try these various food combinations in training to ensure they are acceptable during exercise!

In ultra-type efforts, expect your stomach to revolt eventually. If you’re counting on eating only strawberry-banana gels for your hundred-mile race, this revolt will doom you. Having a variety of food options available will allow you to pivot to something tolerable and keep rolling through the day!

Pro Tip: I make a massive batch of burritos and curry wraps every few weeks, wrap them individually in foil, then freeze them. The night before a big adventure day, I pull one out and thaw it on the counter. Having pre-made food is a huge time saver and has improved my overall nutrition strategy.


The most important time for fuelling is immediately (30-60 minutes) after exercise. You want to give your body the fuel it needs to recover from exercise and build back up to (better than) full strength. Your post-exercise fuel should include the following three components:

Carbohydrates (200-400 calories – sport drink, energy bar, etc…)

Protein (15 grams – PB&J sandwich, yogurt cup, chocolate milk, etc…)

Fluids (1-1.5 L water with electrolytes or sport drink)

After running and climbing for nearly 20 hours in the Tantalus Range in BC this summer, my friend Justin met me at my car at midnight with a large pepperoni pizza and two bottles of Gatorade. It wasn’t what you think of a perfect sport science recovery meal, but it ticked all the boxes and tasted incredible.


Modern running vests and belts make fuelling on the fly easy. The calorie per hour recommendation above is best followed by sipping and snacking frequently rather than in a large hourly bolus! Frequent bites are easier to get in when you’re breathing hard and easier to digest!

Hikers and climbers can take note from runners and start using some of these strategies as well! Equipment design is coming along nicely but many packs used by hikers and climbers have no easy access. Stopping to eat or drink meant taking the whole pack off, digging through it, and then putting it back on. This is time lost, and something of an effort if you’ve got a heavy bag, so often fuelling is overlooked except at major break points. More frequent fuelling allows you to stick to the principles above. Choose a pack with should strap hydration flask holders or pockets with easy access to water bottles and snacks. This will allow you to actually eat the food you’re carrying while continuing to cover ground!

 Pro Tip: Running belts that fit a cell phone, a few bites of food, and a small soft flask of fluid are incredibly comfortable and useful for hikers and climbers. Even under a harness, you can fit a few things in the belt for easy access. So, if your pack isn’t optimized for easy access, check out a run belt!