How to Fuel Your Runs: 10K, Half Marathon & Marathon
You can have the perfect pair of running shoes, follow your training plan for months and arrive on the start line feeling fitter than ever.
But as the distance increases, how you fuel your run can have a major impact on how you perform.
For shorter races, you may need very little during the run itself.
For a marathon, getting enough carbohydrate into your body becomes a much bigger part of the challenge.
So how much fuel do you actually need for a 10K, half marathon or marathon?
Let's break it down.
Why Do Runners Need Carbohydrates?
Carbohydrate is an important fuel source during running, particularly as exercise intensity increases.
Your body stores carbohydrate primarily as glycogen in your muscles and liver.
The problem is that these stores are limited.
As you continue running, particularly during prolonged exercise, your available carbohydrate stores gradually decrease.
Consuming carbohydrate during longer runs and races provides an additional source of fuel and can help support performance as the distance increases.
That's where products such as gels, chews and carbohydrate drinks become useful.
You can explore our full range of energy gels and running nutrition, which includes gels, chews, bars and drink-based options.
How Much Carbohydrate Do You Need While Running?
The amount you need depends largely on how long you're going to be running.
As a general guide:
| Running Duration | Carbohydrate During Exercise |
|---|---|
| Under approximately 60 minutes | Usually little or none required |
| Around 1–2.5 hours | Approximately 30–60g per hour |
| Longer than approximately 2.5 hours | Around 60–90g per hour may be appropriate if practised and tolerated |
These aren't numbers every runner must hit.
Your pace, race duration, previous nutrition, training status and gastrointestinal tolerance all matter.
Someone completing a half marathon in 1 hour 20 minutes has very different fuelling requirements from someone completing it in 2 hours 30 minutes.
That's why it's usually more useful to think about time rather than distance alone.
How Should You Fuel a 10K?
For many runners, a 10K doesn't require any carbohydrate during the race itself.
If you're finishing in around 40–60 minutes and you've eaten normally beforehand, your existing carbohydrate stores should generally be sufficient.
Before the race
Have a familiar carbohydrate-focused meal or snack before running, allowing enough time for comfortable digestion.
Depending on your normal routine and race timing, this could include foods such as:
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Porridge
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Toast
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Banana
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Cereal
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Bagel
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Rice
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A familiar sports nutrition product
There's no need to dramatically change your diet for a 10K.
During the race
For most runners completing the race in under approximately an hour:
You probably don't need a gel during the 10K.
Taking one isn't automatically harmful, but it may offer relatively little benefit if you're finishing shortly afterwards.
Some runners instead choose to take carbohydrate shortly before the start.
For runners who expect to be exercising considerably longer than an hour, taking some carbohydrate during the race may become more relevant.
Example 10K strategy
2–3 hours before: Familiar carbohydrate-rich breakfast
15–30 minutes before: Optional carbohydrate/gel depending on preference
During: Usually no additional fuel required
After: Normal recovery meal and fluids
Keep it simple.
How Should You Fuel a Half Marathon?
The half marathon is where during-race fuelling starts becoming considerably more important for many runners.
For runners spending around 1–2.5 hours on the course, approximately 30–60g of carbohydrate per hour provides a useful general range.
But that doesn't mean you should suddenly consume 60g every hour if you've never done it before.
Start with what you tolerate and practise your strategy during training.
How Many Gels Do You Need for a Half Marathon?
This depends on two things:
How long you'll be running and how much carbohydrate is in each gel.
Not every gel contains the same amount of carbohydrate.
Imagine your chosen gel contains 25g of carbohydrate.
If you're targeting approximately 50g per hour, that's roughly equivalent to two of those gels per hour.
For a runner expecting to finish in around two hours, that could mean approximately three to four gels during the race depending on whether they also take carbohydrate immediately before the start or get carbohydrate from drinks.
But this is only an example.
Always check the nutritional information on the specific product you're using.
Example half-marathon strategy
For someone expecting to run for approximately 1 hour 45 minutes to 2 hours:
2–3 hours before: Familiar carbohydrate-rich breakfast
15–30 minutes before: Optional gel or other carbohydrate source
Around 30 minutes: First race fuel
Around 60 minutes: Second race fuel
Around 90 minutes: Third race fuel
Additional carbohydrate may be appropriate depending on your target intake, finishing time and the carbohydrate content of your chosen products.
The important point is to start fuelling before you feel depleted.
Don't wait until you suddenly feel like you've run out of energy.
How Should You Fuel a Marathon?
The marathon is a completely different nutritional challenge.
Most recreational runners will be exercising for somewhere between three and five-plus hours.
At that duration, your body's stored carbohydrate becomes increasingly important, and consuming carbohydrate throughout the race can play a significant role in maintaining performance.
For prolonged endurance exercise, carbohydrate intake can move towards approximately 60–90g per hour, provided you've trained your gut and can tolerate it.
You don't necessarily need to immediately target the top end of that range.
A runner successfully consuming 60g per hour throughout their marathon may be much better off than someone attempting 90g per hour without having practised it and developing severe stomach problems.
How Many Gels Do You Need for a Marathon?
Potentially quite a few.
Again, it depends on the carbohydrate content of your chosen gel.
Let's use a simple example.
If one gel provides 25g of carbohydrate:
2 gels per hour = approximately 50g/hour
2½ gels per hour = approximately 62.5g/hour
3 gels per hour = approximately 75g/hour
Over a four-hour marathon, that can quickly become a significant amount of fuel.
This is why marathon nutrition shouldn't simply be:
“I'll bring four gels and take one whenever I feel tired.”
Work backwards from:
Your expected finishing time → your target carbohydrate intake → the products you're using.
Example Marathon Fuelling Strategy
Imagine you're targeting a four-hour marathon and have successfully practised consuming approximately 60g of carbohydrate per hour.
If your chosen gels contain 30g each, you could theoretically obtain that from approximately two gels per hour.
But you don't necessarily have to get all of your carbohydrate from gels.
Your intake might instead combine:
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Energy gels
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Chews
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Carbohydrate drink
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Sports drink
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Other familiar carbohydrate sources
For example:
Before the race: Carbohydrate-focused breakfast
15 minutes before: Gel
30 minutes: Fuel
60 minutes: Fuel
90 minutes: Fuel
120 minutes: Fuel
Then continue according to your planned carbohydrate target and the nutritional content of the products you're using.
The exact schedule is less important than consistently meeting a practised intake that your stomach tolerates.
Don't Count Gels — Count Carbohydrates
This is one of the most useful changes you can make to your race nutrition.
Instead of asking:
“How many gels do I need?”
Ask:
“How many grams of carbohydrate am I aiming for each hour?”
Different products contain different quantities of carbohydrate.
A gel containing 20g isn't nutritionally equivalent to one containing 40g.
The same applies to chews and drink mixes.
Once you understand your approximate hourly carbohydrate target, you can build a strategy using whichever combination of products you prefer.
You Don't Have to Use Gels
Energy gels are popular because they're compact, easy to carry and provide a predictable quantity of carbohydrate.
But they're not your only option.
Our energy gels and running nutrition collection also includes options such as:
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Energy chews
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Gummies
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Energy bars
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Carbohydrate drinks
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Sports beans
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Drink mixes
Some runners love gels.
Others find that consuming a mixture of textures and formats makes longer races easier.
The best strategy is the one that provides enough carbohydrate and that you can actually tolerate for the entire race.
What About Maurten?
Maurten offers several different carbohydrate formats designed for endurance sport, including gels and drink mixes.
Because different Maurten products contain different amounts of carbohydrate, you can use them to build a strategy around your target intake rather than simply taking a fixed number of products.
For example, Maurten's own current race guides recommend different quantities depending on race distance and expected finishing time.
You can explore the full Maurten range.
Regardless of the brand you choose, check how much carbohydrate each serving contains and practise your intended combination during training.
What About Hydration and Electrolytes?
Carbohydrate is only one part of your race nutrition strategy.
You also need to consider fluid and, depending on your sweat losses and conditions, electrolytes.
How much you need to drink is highly individual.
A heavy sweater running a warm marathon may have very different fluid requirements from someone racing a cool 10K.
We've covered this separately in our guide to why sodium is crucial for running performance.
You can also read our guide to cramping, heavy sweating and stomach issues if you're struggling to find a hydration and fuelling strategy that agrees with you.
Should You Use Caffeine?
Caffeine is included in some energy gels and sports nutrition products and can be useful for endurance performance.
But more isn't automatically better.
If you plan to use caffeinated products during a race, pay attention to your total caffeine intake, including coffee, pre-workout drinks and multiple caffeinated gels.
Don't accidentally consume large quantities simply because every gel you've packed happens to contain caffeine.
If you're going to use caffeine on race day, practise the strategy beforehand and make sure you know how you respond to it.
The Biggest Race-Fuelling Mistake: Starting Too Late
A common mistake is waiting until you feel tired before taking your first gel.
By then, you're trying to solve a problem that has already started.
For longer races, think of fuelling as maintaining your available energy rather than rescuing yourself once you're exhausted.
Start according to your planned schedule and continue consistently.
Setting an alert on your running watch can be useful if you tend to forget.
Practise Your Race Nutrition During Long Runs
Your long runs aren't only training your legs.
They're also where you should practise your nutrition.
Use them to test:
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How much carbohydrate you can comfortably consume
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Which gels or chews you prefer
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Whether carbohydrate drinks work for you
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How often you want to fuel
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How much water you need
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Whether caffeinated products agree with you
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How you'll physically carry everything
This is particularly important when preparing for a marathon.
You don't want race day to be the first time you've attempted to consume 60g or more of carbohydrate every hour.
Gradually practise the strategy you intend to use.
A Simple Race-Fuelling Checklist
Before race day, you should ideally know:
1. Your expected finishing time
This helps determine how long you'll need to fuel.
2. Your approximate carbohydrate target per hour
Don't just count gels.
3. How much carbohydrate is in each product
Check the label.
4. When you're going to start fuelling
Don't wait until you're exhausted.
5. How you'll carry your nutrition
Belt, pockets, vest or race-provided nutrition.
6. What will be available on the course
Check before race day rather than assuming.
7. Whether you've successfully practised the strategy
Probably the most important step of all.
The Takeaway
Your fuelling requirements change significantly as race duration increases.
10K: Many runners will need little or no carbohydrate during the race itself, particularly when finishing within approximately an hour.
Half marathon: For runners exercising for around 1–2.5 hours, approximately 30–60g of carbohydrate per hour is a useful general range.
Marathon: As duration increases beyond approximately 2.5 hours, carbohydrate intake may move towards 60–90g per hour, provided it has been practised and is well tolerated.
Don't simply copy another runner's gel strategy.
Think about how long you'll be running, how much carbohydrate you're targeting and how much carbohydrate your chosen products actually provide.
Then practise it.
By race day, taking on fuel should feel like another familiar part of your running routine — not an experiment.
