Fuel Is Not Optional
Why skipping carbs on long runs is costing you more than you think
There’s a moment every runner knows — when a run that felt smooth a minute ago suddenly turns heavy.
Your breathing’s fine. Your form’s solid. Everything’s clicking… until it isn’t. The legs stay moving, but the drive’s gone. The run that started strong starts to feel like a grind with every step.
That’s not weakness. That’s a fuel problem — or more accurately, the lack of it.
Most runners mistake that feeling for lack of fitness, or worse, lack of grit. We’re often taught that “real” toughness means running through it. No gels, no water, no excuses. One more rep, one more mile. Just pride pushing you forward.
When I first started running, I fell for that mindset. I listened to all the wrong advice. I’d head out fasted, skip fuel, and call it discipline. I told myself I was training to be tough out there — and if I carried nutrition, it felt like cheating.
But the truth was simpler: I wasn’t training endurance — I was just testing how long I could run on empty.
I learned the hard way that effort alone isn’t enough. You can train hard, stay consistent, and still fade halfway through runs that should feel strong. Not because you’re unfit — but because you’re underfed.
Fueling isn’t optional. It’s essential. Most runners aren’t short on effort; they’re short on energy.
“You can’t pour from an empty cup.” — Eleanor Brownn
If your training keeps hitting the same wall, it’s not effort—it’s energy. Book your FREE discovery call and learn how to match your fuel to your goals.
The Pride of Running on Empty
You see it at every start line on race day — runners standing there with nothing but grit in their gut. No gels. No chews. No carb mix. Just pride, adrenaline, and the belief that toughness alone will get them through.
For some, it’s a badge of honor — the “I don’t need that stuff” crowd. They’ll line up fasted, shrug off nutrition talk, and tell themselves that real endurance means earning it the hard way. Maybe they’ll grab a cup of water at an aid station, but that’s it.
I’ve seen it everywhere — marathons, triathlons, trail races, Spartans. Runners who trained hard, did the miles, built the fitness… and still showed up determined to prove they could out-grit biology.
For some, it’s lack of understanding. But for far too many, it’s identity and ego. Fueling looks like a compromise — like admitting they’re human instead of heroic. And there’s a certain pride in that suffering, the kind that says, If it doesn’t hurt, it doesn’t count.
Skipping fuel feels like toughness — until you realize it’s just pride in disguise. Because running on empty doesn’t build endurance; it only feeds the ego.
The Science of Hitting the Wall
Every move you make burns energy — not just running, but sitting, walking, even sleeping. Your body gets that energy from two main fuels: fat and carbohydrates.
At rest, when you’re sleeping or sitting at your desk, your body runs mostly on fat. Think of it like a slow-burning log on a campfire — steady, reliable, and built for long durations. You don’t need much oxygen or effort to keep that flame going.
But as soon as you start moving — walking briskly, climbing stairs, or heading out for a run — your body needs energy faster. The harder you breathe, the more your body shifts toward carbohydrates. Carbs burn hotter and faster than fat — the higher the effort and harder it is to breathe, the more your body leans on them. The higher the effort, the more your system leans on them to keep the fire roaring.
Fat is plentiful — even the leanest athlete has hours of it stored — but it burns too slowly to sustain hard effort on its own. Carbs, on the other hand, are limited. You only have a small supply available in your blood and muscles, and once that’s gone, the flame starts to die down.
That’s the wall.
Your body still has fuel left, but not the kind it can burn fast enough to match the effort you’re asking for. So you’re forced to stop.
Fueling isn’t about shortcuts or making it easier — it’s about keeping that fire burning strong. Every sip, chew, or gel is like tossing a handful of kindling onto the flame to keep the heat steady. Because when the fire fades, so does your ability to keep moving the way you want to.
Training the System That Carries You
Fueling isn’t just about finishing a single run — it’s about building a system that can keep up with the work you’re asking from it. Just like your legs and lungs, your gut needs training too. The goal is to teach your body to take in energy, absorb it, and keep moving smoothly under effort.
Here are three simple places to start:
Before you start: Take in 30–60 grams of carbohydrates about 30–60 minutes before your run. That could be half a banana, a slice of toast with honey, or a small carb drink. The goal isn’t to stuff yourself — it’s to top off the tank so your body doesn’t start behind. On early-morning runs, even a few sips of sports drink is better than nothing.
How much: Aim for roughly 30–60 grams of carbohydrates per hour on runs longer than 60 minutes. Start on the lower end — 30 to 40 grams — to avoid stomach issues, and gradually work up as your gut adapts. Some newer, higher-carb protocols push 80–90 grams per hour (or more), but those take time, practice, and a bit more precision to get right.
When: Begin fueling around the 30-minute mark and continue every 15–20 minutes after that, or roughly once every mile if that’s easier to remember. Small, steady doses keep your energy stable and are easier to digest than large, infrequent hits. Don’t wait until you feel empty — once you’re low, it’s hard to come back.
What: Choose what you can stomach. Gels, chews, drink mixes, or real food like dates or gummies all work. Experiment on long runs — both what you use, and when and how much. Test different timing and portion sizes to see what your body handles best and which options still taste okay deep into the effort.
Most runners will feel and perform better fueled than fasted. The key is knowing what your body responds to — and that takes practice.
Fueling isn’t a hack — it’s part of the work. When you treat energy as essential, every mile becomes one that your body can actually learn from.
After hitting the wall hard in my last half Ironman, I finally stopped trying to “tough it out.”
I’d done the training. I’d hit every session. But when the energy tanked, pride wasn’t enough to pull me through. Since then, I’ve spent months dialing in my fueling — learning what works, testing timing, figuring out what my stomach can actually handle when I’m deep in the effort.
Fueling isn’t the flashy part of training, but it’s the one that changes everything. The right energy keeps you steady, strong, and able to turn hard work into lasting progress.
Because endurance isn’t about proving how long you can suffer — it’s about giving your body what it needs to go the distance well.
What would change in your training if you stopped treating fuel like a backup plan and started seeing it as part of the work?