How to Fuel for Endurance

Fuelling for endurance sport doesn't need to be complicated.

Whether you're running a marathon, racing an ultra, riding for hours or simply heading out for a long training session, the basic principle is the same:

Give your body a steady supply of carbohydrate, fluid and electrolytes before you start running low.

The best strategy isn't the one with the biggest numbers or the most products. It's the one you can practise, repeat and execute when you're tired.

Here's how to build yours.

The Three Things You're Managing

For most endurance sessions, think about three things:

Carbohydrate — your main fuel source for sustained and higher-intensity exercise.
Fluid — replaces some of the water you're losing through sweat.
Electrolytes — particularly sodium, which is also lost through sweat.

How much you need depends on the duration and intensity of the session, the conditions and the individual athlete.

There isn't one perfect number for everyone.

1. Start With Carbohydrates

Your body stores carbohydrates as glycogen in your muscles and liver.

Those stores are limited and the longer and harder you exercise, the more important it becomes to take carbohydrates on board during the session rather than relying entirely on what you started with.

As a practical guide:

Under 60 minutes

For most sessions, you probably don't need carbohydrate during the activity.
Start well fed and concentrate on hydration where required.

1–2 hours

Aim for around 30–60g carbohydrate per hour.
This could be a carbohydrate drink, gel, chews or a combination.

2–3 hours

Aim for approximately 60–90g carbohydrate per hour.
At this point, having a proper fuelling strategy becomes increasingly important.

3+ hours

60–90g+ per hour is a useful range for many endurance athletes.

Some athletes can successfully consume more than 90g per hour, particularly during long races, but higher isn't automatically better.

Build towards what supports your performance and works consistently for you and remember intensity will dictate the carb need.  Higher intensity = more carbs required

2. Start Early

One of the biggest mistakes in endurance fuelling is waiting until you feel hungry, flat or low on energy.

By then, you're already playing catch-up.  If you're doing a long session or race, start taking fuel on board early and continue throughout.

Rather than thinking:

"I'll have something when I need it."

Think:

"I'm going to give my body a steady supply of energy from the beginning."

For longer events, starting within the first 20–30 minutes and continuing regularly can make the whole strategy easier to manage.

3. Fuel Little and Often

You don't need to consume an entire hour's carbohydrate at once.

Spread it across the hour.

If your target is 60g per hour, for example, you might take roughly 20g every 20 minutes.
If your target is 90g per hour, you could take approximately 30g every 20 minutes.

It doesn't have to be mathematically perfect.

The important thing is consistency.

Small, regular amounts are also much easier to remember than trying to rescue your fuelling after you've forgotten about it for 90 minutes.

4. Build Your Fuel Around What You Actually Like

Carbohydrates can come from:

• Carb drinks
  
• Gels
  
• Chews
  
• Bars
  
• Real food
  
• Or a combination of them

There's no rule saying everything has to come from one product.

In fact, mixing formats can make longer events much easier.

You might use a carbohydrate drink as your steady base, add gels when you want something quick and easy, and introduce solid food during a longer ultra.

Your body doesn't care about brand loyalty. It cares about getting enough usable fuel.

5. Using Highland Fuel

We've deliberately made Highland Fuel easy to build into a wider strategy.

Rather than telling you that our product has to be your entire nutrition plan, use it wherever it works best for you.

For example, you could use BareFuel as your base carbohydrate drink, then supplement it with gels, chews or food to reach your hourly target.

If you're aiming for around 60–90g of carbohydrate per hour, that might look like:

Carb drink + gel
or
Carb drink + chews
or
Carb drink + food

or simply

More carb drink

There isn't one correct combination.

Find the one that is easiest for you to execute.

6. Don't Forget Fluid

Fuelling and hydration are connected, but they're not the same thing.

Your fluid requirements can change enormously depending on:

• Temperature
  
• Humidity
  
• Exercise intensity
  
• Your individual sweat rate
  
• How much you're wearing
  
• How long you're exercising

Around 400–800ml per hour can be a useful broad starting range for many endurance situations, but it shouldn't be treated as a fixed target.

A cool Scottish winter long run and a summer race in 30°C heat clearly don't require the same hydration strategy.

Pay attention to conditions and learn what your own body needs.

7. Think About Sodium Too

When you sweat, you lose both water and electrolytes, particularly sodium.

How much sodium you lose varies considerably between athletes.

Some people finish a run barely marked.

Others look like they've been rolled in salt.

Longer events, hotter conditions and heavier sweating generally make sodium replacement more important.

Your sports drink may already contain sodium, so remember to count that before automatically adding electrolyte capsules or tablets.

More sodium isn't automatically better.

The goal is replacing an appropriate amount for you and the conditions.

8. Practise Your Race-Day Strategy

Don't build your perfect nutrition spreadsheet the night before your race.

Long runs, long rides and race-specific sessions are opportunities to work out:

• How many carbs you can comfortably consume
  
• How often you prefer to fuel
  
• How much fluid you normally drink
  
• Which products are easiest to use
  
• What flavours you still want after several hours
  
• How you're going to carry everything
  
• How your strategy changes in hot or cold conditions

By race day, your fuelling shouldn't be an experiment.

It should feel familiar.

9. Increase Carbohydrates Gradually

If you're currently consuming 30–40g of carbohydrate per hour, don't suddenly decide you're going to race at 100g per hour.

Build up tolerance in training.

Try 50g.
Then 60g.
Then 70g.

Keep increasing it during appropriate training sessions if you feel you'd benefit from more.

The ability to consume carbohydrate during exercise can be trained just like other parts of endurance performance.

10. Have a Race-Day Plan

Before a long race, know roughly what you're going to consume.

For example:

Target: 75g carbohydrate per hour

Over a four-hour event that's approximately:

300g carbohydrate in total.

You don't necessarily need to carry all 300g from the start if there are aid stations or drop bags available, but knowing the overall requirement makes planning much easier.

Then decide where it's coming from.

Maybe your drink provides 50g each hour and you add another 25–30g from a gel.

Simple.

11. But Don't Become a Slave to the Numbers

Your plan is a framework, not a contract.

Conditions change.

Pace changes.

You might drink more because it's hot.

You might want less solid food later in an ultra.

You might miss a gel because you're halfway up a mountain when your watch beeps.

That's endurance sport.

The objective isn't to hit exactly 78.4g of carbohydrate every hour.

It's to maintain a consistent supply of energy across the event.

Look at the bigger picture.

A Simple Starting Strategy

If you're new to endurance fuelling, don't overthink it.

For a longer training session:

Start around 60g carbohydrate per hour.

Take some every 20–30 minutes.

Drink according to conditions and thirst.

Include sodium appropriate to your sweat losses.

See how you feel.

Then adjust.

Once that feels completely normal, you can experiment with increasing carbohydrate intake if your training or racing demands it.

The Golden Rules

• Start fuelled.
  
• Start fuelling early.
  
• Eat little and often.
  
• Aim for consistency rather than perfection.
  
• Practise before race day.
  
• Use whatever combination of drinks, gels, chews and food works for you.
  
• Adjust fluid and sodium for the conditions.
  
• Don't copy someone else's numbers simply because they're bigger.

A good endurance nutrition strategy should eventually become boring.

You know what you're taking.

You know when you're taking it.

You've tested it in training.

And when race day arrives, you can concentrate on racing rather than worrying about nutrition.

Simple. Repeatable. Built for long days.

Scoop. Sweat. Suffer. Succeed.
Steve | Founder