Fuelling for Performance: Why Carbohydrates (and How You Take Them) Matter

When runners talk about performance, shoes usually steal the spotlight. But no matter how dialled your footwear is, there’s one truth that remains constant:

You can’t outrun empty fuel stores.

Modern sports nutrition is clear: adequate fuelling is one of the biggest performance differentiators for endurance athletes. It affects not just race day outcomes, but training quality, recovery, injury risk, and long-term health. And at the centre of it all? Well, have you ever heard the phrase, “More pasta, run faster?” We are talking about carbohydrates, in all of their forms, of course! This guide breaks down why carbs matter, how much you actually need, and why the way you consume them is just as important as the amount. 

Expert Credit: Rachel Hannah, RD, Our Trusted Fuelling Speaker

Not only are we drawing on the latest research and the fuelling systems used by elite runners worldwide, but this guide also draws heavily on the recent presentation given at BlackToe Running by Rachel Hannah, RD—a longtime friend and trusted expert in the running community. Rachel isn’t just a registered dietitian and sports nutrition consultant; she’s also an elite competitive runner with some of Canada’s top performances to her name, including multiple national championships and a Pan Am Games marathon bronze medal.

Her dual lens, as both a clinician with a decade of nutrition experience and an athlete who practices what she preaches, makes her insights especially valuable for runners of all levels. BlackToe is proud to partner with Rachel and share her evidence-based expertise with our community. Let’s run!

Why Fuelling Matters More Than You Think

Carbohydrates are the body’s primary fuel source during moderate to high-intensity running. As pace increases, your reliance on carbs skyrockets, especially during races and hard workouts.

The challenge? Your carbohydrate stores are limited:

• Liver glycogen: ~50–100g

• Muscle glycogen: ~250–650g

Once those stores run low, performance drops sharply. This is why late-race fatigue, slowing splits, and “the wall” exist, and why fuelling during runs isn’t optional; it’s essential!

Research consistently shows that:

• Higher carbohydrate intake per hour = better endurance performance

• Athletes who fuel consistently maintain pace longer and fade less late in races

• Under-fuelling increases injury risk and slows recovery

In short: finishing tired is normal. Finishing empty is avoidable.

How Much Fuel Do Runners Actually Need?

Fuelling recommendations depend on duration, intensity, and experience, but modern guidelines are much higher than many runners expect.

General endurance fuelling targets:

• 45–75 minutes: light fuelling or optional

• 60–150 minutes: ~30–60g carbs per hour

• 150+ minutes: up to 90g carbs per hour (with gut training)

That means for marathon and long-distance racing, fuelling early and often isn’t aggressive, but optimal. One simple rule of thumb:

Start early. Fuel every 20–30 minutes. Don’t wait until you feel low.

The Hidden Problem with Traditional Fuelling

If carbs are so important, why do so many runners struggle to hit higher intake targets? For starters, the gut has limits. Highly concentrated carbohydrate drinks and gels can:

• Slow gastric emptying

• Delay fluid absorption

• Cause GI distress (sloshing, bloating, nausea)

This creates a frustrating scenario for many athletes: your muscles want more fuel, but your stomach can’t handle it. This is where modern sports nutrition technology comes in, such as hydrogel-based fuelling that has been pioneered by brands like Maurten. Instead of behaving like a liquid in the stomach, hydrogel fuels are unique in the following ways:

1. They form a gel structure when they hit stomach acid

2. They encapsulate the carbohydrates

3. They pass efficiently into the intestine

4. They release carbohydrates where absorption is optimized

The result? Higher carb delivery with less GI stress. This is what allows runners to:

• Take in more fuel per hour

• Maintain hydration, energy, and output

• Fuel more aggressively without dreaded tummy troubles
  

Quick Fuelling Playbook

Your long run & race day quick guide:

• Goal: Maintain carbohydrate availability

• Target: 30–90g carbs per hour (depending on duration & gut training)

• Timing: Start early, fuel every 20–30 minutes

• Best Tools: Hydrogel-based gels and drink mixes

• Key Tip: Practice race-day fuelling in training—gut training matters

What This Means for Training (Not Just Race Day)

Fuelling isn’t only for marathons. In fact, how you fuel during training determines how well you race. Smart fuelling supports:

• Higher quality workouts

• Faster recovery between sessions

• Better adaptation to training load

• Improved tolerance to carbs on race day

Practicing your fuelling strategy during long runs and key workouts is known as gut training — and it’s a critical step for runners aiming to increase carbohydrate intake safely.

“Fuel early and consistently, not just on race day, but in training. The goal isn’t to finish feeling depleted; it’s to finish having supported the work you asked your body to do.”

— Rachel Hannah, RD. Rachel Hannah is a registered dietitian, elite Canadian marathoner, and longtime member of the BlackToe community. Her approach to fuelling is grounded in current research and shaped by years of competing (and winning!) at the highest level.

Need Help Dialling In Your Fuelling Strategy? Visit Us At BlackToe Running!

At BlackToe Running, we don’t just sell nutrition: we help runners understand how to use it. Whether you’re training for your first half-marathon or chasing a PR, our team can help you choose the right fuel for your goals, understand how to use it during training, and support the unique needs of your body and training plan. Visit us in-store or online to explore our wide selection of the industry’s most cutting-edge sports nutrition products, including Maurten, Precision, Science in Sport (SiS), Tailwind, GU, and more!