One of the most common mistakes I see among half marathon runners has nothing to do with fitness.
It has nothing to do with speed work, long runs, or running form.
It happens when they reach for their first gel.
Specifically, it happens when they wait too long.
Many runners approach fueling as a reaction rather than a strategy. They start feeling tired, notice their pace beginning to fade, and then decide it’s time to take some fuel.
Unfortunately, by that stage, they’re already behind.
If you want to run your best half marathon, you need to fuel before you think you need it.
Why Half Marathons Are Long Enough to Require a Plan
A half marathon sits in an awkward middle ground.
It’s short enough that some runners assume they can get through without taking fuel.
Yet it’s long enough that poor fueling decisions can significantly impact performance.
For many runners, especially those racing for 90 minutes or longer, carbohydrate availability becomes increasingly important as the race progresses.
Your body stores carbohydrates as glycogen in your muscles and liver. During a half marathon, especially when you’re running at race pace, those stores are being used continuously.
The faster you run, the greater your reliance on carbohydrates.
The goal isn’t necessarily to completely replace what you’re using.
The goal is to slow the rate at which you’re running low.
The Problem With Waiting
Imagine driving a car on a long journey.
You don’t wait until the engine stops before thinking about fuel.
You pay attention to the fuel gauge and top up before you reach empty.
Race nutrition works much the same way.
Many runners wait until they feel tired, sluggish, or mentally flat before taking a gel.
The problem is that fuel takes time to be absorbed and utilised.
A gel taken after the energy drop won’t immediately solve the problem.
That’s why experienced runners often begin fueling relatively early in the race.
The goal is prevention, not rescue.
What Happens When Energy Starts To Drop?
If you’ve ever felt strong through halfway and then struggled badly over the final few kilometres, you’ve experienced it.
Your pace starts drifting.
Maintaining effort becomes harder.
Your form deteriorates.
Small hills feel bigger.
Mentally, everything feels more difficult.
Many runners assume this means they need more training.
Sometimes they do.
But often, the issue is simply that they failed to support the fitness they already had.
Practice During Long Runs
One of the biggest mistakes runners make is saving their fueling strategy for race day.
Your long runs should be rehearsals.
Use them to answer important questions:
- What breakfast works best for you?
- Which gels sit comfortably in your stomach?
- How much fluid do you need?
- When should you take your fuel?
- What happens if you fuel earlier versus later?
Every long run provides an opportunity to refine your strategy.
By race day, nothing should be a surprise.
Train Your Gut
Most runners understand that muscles adapt to training.
What many don’t realise is that your digestive system adapts too.
If you never consume carbohydrates during training, suddenly asking your stomach to process gels while running hard on race day can create problems.
Regular practice improves your body’s ability to tolerate and absorb fuel during exercise.
Just like your cardiovascular system adapts to training, your gut can adapt as well.
That’s why practising race nutrition is every bit as important as practising race pace.
Keep Your Strategy Simple
You don’t need an elaborate spreadsheet.
You don’t need a different product every 20 minutes.
You simply need a plan.
Know what you’re taking.
Know when you’re taking it.
Practise it often enough that it becomes automatic.
Simple plans are usually easier to execute under race-day pressure.
Fueling Supports the Fitness You’ve Built
Good nutrition won’t replace consistent training.
But poor nutrition can absolutely prevent you from performing to your potential.
The goal isn’t to finish the race wishing you’d fuelled earlier.
The goal is to reach the final 5 kilometres with enough energy to keep pushing.
Because that’s where half marathons are often decided.
Not by who trained the hardest.
But by who executed their race plan best.
Ready to Run Your Best Half Marathon?
Whether you’re training for your first half marathon, chasing a personal best, or trying to avoid the common mistakes that hold runners back, having the right plan can make all the difference.
If you’d like some help identifying the best path to your goal, book a free, no-obligation 40-minute coaching consultation.
We’ll discuss your current training, your race goals, what’s working well, and where the biggest opportunities for improvement might be.
No pressure. No hard sell. Just practical advice to help you move forward with confidence.