Trail Running Fueling: A Practical Guide for Canadian Trail Runners

You are three hours into a technical trail, picking your way down a rooty descent, and your legs are fine. That is the strange part. The legs have plenty left. What is missing is upstairs: focus gone soft, foot placement getting sloppy, decisions arriving a half-second late. You read it as fatigue and tell yourself to toughen up. It is not toughness you are short on. It is glucose, and your brain runs on it as surely as your muscles do.

Under-fuelling on trail shows up as a cognitive problem before it becomes a muscular one, and on technical terrain that is dangerous as well as slow. This is a practical trail running fuelling guide for Canadian runners: how much carbohydrate to take by distance, what is realistic to carry, how a flask of mix compares with a pocket full of gels, and the cold-weather considerations that road-running advice ignores. The goal is keeping the lights on upstairs for the whole run, not just the legs.

What makes trail different from road running

Trail running is a different fuelling problem than the road for three reasons. The pace is uneven, surging on climbs and braking on descents, which burns carbohydrate less predictably than a steady road tempo. The footing demands constant attention, so the cognitive cost of running is higher, and a fuelled brain matters more. And trail efforts tend to last longer than a road run of equivalent perceived effort, because the terrain slows you down while the time on feet climbs.

That combination means you are out there longer, working your nervous system harder, and burning fuel in surges, all while carrying everything you need on your back. Road fuelling advice assumes aid every few kilometres and smooth, automatic running. Trail assumes neither. The plan has to account for self-sufficiency and for the fact that your brain is doing real work, not just your legs.

Carbohydrate per hour by distance

For sub-marathon trail efforts up to a couple of hours, 30 to 60 grams of carbohydrate per hour is generally enough, scaled to intensity. For a 50k, target 60 to 90 grams an hour and commit to taking it consistently, because the duration will find any gap in your fuelling. For 50 miles and beyond, you stay in that 60 to 90 gram range but the challenge shifts to sustaining intake for many hours without GI breakdown, which is as much a gut-training problem as a fuelling one (Costa et al., 2018).

The recurring trail mistake is letting the terrain dictate fuelling: skipping intake on a hard climb or a technical section because eating felt impossible, then never catching back up. Decide your intake by the clock, not by how the trail feels in the moment. A 2:1 carbohydrate formula helps here because it raises how much you can actually absorb per hour on long efforts, the same logic covered in 120g of carbohydrates per hour.

The pack reality

There is what you wish you were carrying, and there is what is actually in your vest. Trail fuelling lives or dies on this gap. Every gram of fuel and fluid has weight, and weight on a long climb is real. This is the argument for carrying your carbohydrate as concentrated drink mix rather than a bulky pile of individual products: a flask of high-carbohydrate mix packs more usable fuel into less space and weight than the equivalent in gels.

Plan your carry around the time between water sources or aid, not the total distance, because water is the heavy thing you can sometimes refill and fuel is the light thing you cannot. Carry your carbohydrate, plan to top up water, and keep the format simple so you are not managing a dozen wrappers on a technical descent.

Drink mix versus gels versus whole food

Each format has a place, but the economics and logistics favour drink mix as the trail base. Consider the math: a single 250ml hydration flask filled with concentrated Olway® Performance Drink Mix can hold the carbohydrate of three or four gels, at a fraction of the cost per gram and a fraction of the packaging weight and waste. You sip measured carbohydrate without unwrapping anything, and because the mix is unflavoured it does not become sickly over hours the way sweet gels do.

Gels still earn a spot for a fast, convenient hit, particularly late in a race when you want something instant. Whole food, a bar, a boiled potato with salt, a handful of chews, helps with palate fatigue and the psychological need to chew on very long efforts. But the foundation that carries the hours is liquid carbohydrate, supplemented by the others, not the other way around. The cost side of this is worked through in what it actually costs to fuel a four-hour ride, and the logic transfers directly to trail.

Aid station strategy

Aid stations are where time is won and lost, and where good intentions go sideways. Arrive with a short plan for each one: refill water, refill or swap your flask of mix, grab a specific food you know sits well, and move. The trap is treating the aid station as a buffet, eating too much of something untested, then running into a climb with a heavy, unhappy stomach.

Do the high-value tasks first, fluid and fuel for the next section, and only then consider anything extra. Carry a small supply of your own mix so you can refill your flask with a known quantity of carbohydrate rather than relying on whatever the table has. Knowing your numbers, how long the next section is and how much you need for it, turns the aid station from a guessing game into a thirty-second pit stop.

Cold-weather and Canadian-trail considerations

Canadian trail running spends a lot of the year in the cold, and cold changes the fuelling problem in ways warm-weather guides skip. Hydration freezes: a flask or bladder hose left exposed on a sub-zero run can ice up, so carry fluids close to your body and consider insulated bottles or blowing the hose clear after drinking. A concentrated mix has a slightly lower freezing point than plain water, a small practical advantage in winter.

Cold also masks thirst, so you under-drink without feeling it, and you still lose meaningful sodium and fluid through sweat under layers on a hard effort, even when it does not feel like it. Keep drinking on schedule rather than to thirst in the cold. And do not let the temperature convince you to fuel less: the work is the same or harder, and the brain still needs glucose. The same principle applies to the hybrid-fitness crowd; if you train across formats, the Hyrox fuelling guide covers overlapping ground.

Frequently asked questions

How many carbohydrates per hour for trail running?
Roughly 30 to 60 grams per hour for efforts up to a couple of hours, and 60 to 90 grams per hour for 50k and beyond. Scale to intensity and your gut tolerance, and take it consistently rather than letting hard terrain interrupt your intake.

What should I carry to fuel a trail race?
A flask of concentrated carbohydrate drink mix as your base, plus a couple of gels for fast hits and some whole food for long efforts and palate variety. Plan your carry around the time between water sources, not total distance.

Is a drink mix better than gels for trail?
For most runners, yes, as the foundation. A flask of concentrated mix carries more usable carbohydrate per gram of weight and per dollar than the equivalent in gels, with less packaging to manage. Gels remain useful as a convenient supplement.

How do I stop my hydration freezing on winter trail runs?
Carry fluids close to your body, use insulated bottles, and clear bladder hoses after each drink. A concentrated drink mix freezes slightly less readily than plain water. Drink on a schedule, since cold suppresses the thirst that would normally remind you.

Keep the lights on

The runners who stay sharp deep into a trail effort are not tougher than the ones who fade. They are better fuelled. Under-fuelling takes the brain offline before it takes the legs, and on technical ground that costs you focus, safety, and time long before your muscles give out. Decide your intake by the clock, carry your carbohydrate as concentrated mix to save weight and money, and treat the cold as a reason to fuel more deliberately, not less.

For the road-running counterpart to this approach, see the marathon fuelling guide, the ratio science is in the 2:1 ratio breakdown, and you can find Olway® at a retailer near you on the stockists page.

References

Costa RJS, Hoffman MD, Stellingwerff T. Considerations for ultra-endurance activities: part 1 – nutrition. Research in Sports Medicine. 2019;27(2):166–181. doi:10.1080/15438627.2018.1502188
Stellingwerff T, Morton JP, Burke LM. A Framework for Periodized Nutrition for Athletics. International Journal of Sport Nutrition and Exercise Metabolism. 2019;29(2):141–151. doi:10.1123/ijsnem.2018-0305
Jeukendrup AE. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine. 2014;44(Suppl 1):S25–S33. doi:10.1007/s40279-014-0148-z