Your marathon fuelling strategy should start well before the race does. In this article, we're going through the main considerations that can influence whether you are able to hold your race pace:

• Your carbohydrate stores
• Your pre-race meal
• Fluid intake
• Sodium
• Caffeine
• Spreading your fuel across the race

Please note, there isn't one plan that suits every runner. Someone finishing in under three hours, for example, has different requirements and opportunities to fuel compared with someone who will be on course for five hours. Your sweat rate, gut tolerance and the conditions on race day also need to come into it. What we're offering is a helpful framework you can follow.

Start the race with your carbohydrate stores full.

Carbohydrate is stored in your muscles and liver as glycogen, and marathon running places a heavy demand on those stores.

This is why carb loading is so common before endurance events. Research suggests well-trained runners can maximise muscle glycogen by reducing training volume and consuming a high-carbohydrate diet over the final 36-48 hours before a marathon.[1] For most athletes, this isn't necessarily an enormous pasta dinner the night before. The aim is to increase carbohydrate intake across the final day or two using foods that you already tolerate well, eg. rice, bread, cereal, oats, pasta, fruit, juice and so on.

As carbohydrate intake increases, it can also help to limit very high-fat and high-fibre foods, as they can take time and energy for your body to digest. The goal is to arrive at the start line well fuelled with energy stores that are ready to use.

Race morning.

Your pre-race meal gives you another opportunity to increase carbohydrate availability before you start. Sports nutrition guidelines are recommending 1-4g carbs per kilogram of body weight, 1-4 hours before exercise, with the exact amount depending on how much time you have available and what you can comfortably tolerate.[2]

This is a pretty broad recommendation, so it's important to test your pre-race meal rather than every runner forcing down 4g/kg before their marathon. A breakfast eaten three hours before the race might be larger than something eaten 60-90 minutes beforehand.

Common options for pre-race meals include:

• toast with jam or honey
• oats or cereal
• banana
• rice or a simple rice-based meal
• sports drink or juice
• a sports bar you've had before

Keep it familiar to your digestion. Race morning is not the time to test a new high-fibre breakfast, a huge serving size or a food you've never eaten before running.

Some athletes also use a small amount of carbohydrate, such as a gel, in the final 10-20 minutes before they start. This can contribute towards carbohydrate availability early in the race but, again, it should be something you have already practised.

During the marathon.

As we discussed in our article on how many carbohydrates per hour you actually need, general endurance recommendations typically sit around:

Race duration	Approx. carbohydrate target
~1–2.5 hours	30–60g/hr
>2.5–3 hours	Up to ~90g/hr

When it comes to marathons, most runners will be exercising for long enough that carbohydrate intake during the race becomes important. Research consistently supports carbohydrate consumption during prolonged endurance exercise, and the benefit generally becomes more significant as exercise duration increases.[3]

Somewhere around 60-90g of carbohydrate per hour is a generally helpful range to work towards for a lot of runners, provided it has been practised and tolerated in training.[2] But this does not mean 90g/hr should be everyone's target. If you've successfully trained and raced at 60g/hr, jumping to 90g because you read that elite runners are doing it may cause more problems than it solves. 

What does 60-90g per hour actually look like?

Let's say a gel contains 30g of carbohydrate and your drink contains 25g per bottle. A runner targeting roughly 80-90g/hr could theoretically get there with:

2 gels = 60g
+ carbohydrate drink = 25g
Total = 85g/hr

Or it could be 3 gels = 90g.

There are plenty of ways to reach the same number. The important part is to count all carbohydrate sources. If your sports drink contains carbohydrates, those grams belong in the total alongside gels, chews or food. You don't want to build a 90g/hr gel strategy and then accidentally add another 30–40g through your drink, and end up feeling bloated or cramping in your race.

Spread your fuel across the hour.

Rather than waiting until you feel flat and then taking a large amount of carbohydrate at once, marathon fuelling is usually easier to manage when it is spread more consistently across the race. For example, someone targeting 60g/hr could take a 30g gel approximately every 30 minutes.

There isn't anything miraculous about those exact intervals, it's more about building a functional routine that gives your body a regular carbohydrate supply and is easy to remember when you're tired.

Starting early helps, too. Don't wait until your 30th kilometer to start re-fuelling because that's when you expect things to get hard. By that stage, you may already be trying to catch up on several hours of under-fuelling.

Don't forget about fluids.

Carbs are only one part: your fluid intake is also a huge component of a good marathon fuelling plan. The amount of fluid should be based on your sweat rate, environmental conditions, pace and access to aid stations.

As we covered in our article on how much sodium you're actually losing, two runners can have very different fluid and sodium losses even when completing the same marathon. This means blanket advice like “drink one litre every hour” doesn't necessarily work for everyone. Ideally, you should use your long training runs to estimate how much fluid you typically lose in conditions similar to race day. Then you can create a drinking plan that limits excessive dehydration without encouraging you to drink substantially more than you are losing.

Sodium.

Sodium becomes more important as your race duration, sweat rate and sweat sodium losses increase. A runner who sweats 500ml per hour with relatively low sodium concentration has a very different requirement to someone losing 1.5 litres of salty sweat every hour.

Look at sodium alongside the amount of fluid you are actually consuming. For example, a drink containing 1,000mg sodium per litre provides:

• 250mg if you drink 250ml
• 500mg if you drink 500ml
• 1,000mg if you drink the full litre 

This sounds obvious, but it is easy to compare electrolyte products based on the number printed on the front without considering how much you're realistically going to drink during the race.

Caffeine.

Caffeine can support endurance performance, but a marathon plan doesn't necessarily require you to take a large dose before the race and then continue adding more all day in the same way as you might with carbs, sodium and fluids.

Some runners like some caffeine before the start, where others use caffeinated gels later in the race when fatigue is becoming more noticeable. The amount you take should factor in your body weight, caffeine tolerance and anything you have already consumed before the race, including coffee and pre-workout.

More isn't necessarily better, and caffeine can also affect the gut, sleep and how some athletes feel during competition. We cover caffeine timing across a race in more detail in another article.

Your marathon plan should already be tested.

This is one of the most important parts. The race itself shouldn't be the first time you've tried:

• your carbohydrate target
• the exact gels you're using
• your carbohydrate drink
• your caffeine strategy
• your fluid intake
• your sodium intake
• the timing between each feed

Your long runs are where you do your testing and practicing. Research shows that repeated carbohydrate feeding during training can improve tolerance and reduce gastrointestinal symptoms, which is why gut training becomes increasingly important when you're working towards higher carbohydrate intakes.[4]

Having race-day fuelling 'rehearsals' also exposes the practical issues you don't think about when you look at your plan on paper. Can you open the gel while running? Does a particular flavour become unbearable after four of them? Do you need water with it? Can you actually carry everything you planned, or do you need to use aid stations? These things all matter when it comes to race day.

What could a marathon fuelling plan look like?

Here is an example plan for a runner who has trained to tolerate around 90g carbohydrate per hour. Again, this is just an example guide, not necessarily a target that every runner should copy.

Timing	Example
2–3 hrs before	Familiar carbohydrate-rich breakfast + fluids
10–15 min before	~30g carbohydrate gel
30 min	~30g carbohydrate
60 min	~30g carbohydrate
80 min	~30g carbohydrate
100 min	~30g carbohydrate
120 min	~30g carbohydrate
Each following hour	Continue ~30g every 20 minutes
Throughout	Fluid according to conditions and individual sweat rate
Later stages	Caffeinated gel if this has been planned and practised

This plan provides approximately 90g of carbohydrate around the opening hour, including the pre-race gel, before settling into approximately 90g/hr during the race. Remember that any carbohydrate-containing sports drinks also need to be included in your total, so gel intake should be adjusted accordingly.

Build the plan backwards from race day.

Before deciding how many gels or drinks you need, work out:

1. How long do you expect to be racing?
A 2:45 marathon and a 5-hour marathon require different plans.

2. How much carbohydrate can you comfortably tolerate per hour?
Use long runs in your training program to find out (not race day).

3. Approximately how much fluid and sodium do you lose?
This is especially important if you're racing in hot weather.

4. What will actually be available on course?
Know where the aid stations are, what they provide and what you need to carry yourself.

Once you've got those pieces, the fuelling plan becomes much easier to build. You don't want to just go for a high intake of carbs, sodium, and fluid - more is not automatically better. Your goal should be to give your body enough fuel and hydration to hold your planned pace.

References.

1. Burke LM. Nutrition strategies for the marathon: fuel for training and racing. Sports Medicine. 2007;37(4–5):344–347.
2. Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Sciences. 2011;29(S1)–S27.
3. Ramos-Campo DJ, et al. The ergogenic effects of acute carbohydrate feeding on endurance performance: a systematic review, meta-analysis and meta-regression. Critical Reviews in Food Science and Nutrition. 2024.
4. Jeukendrup AE. Training the Gut for Athletes. Sports Medicine. 2017;47(Suppl 1):101–110.
5. Stellingwerff T. Contemporary nutrition approaches to optimize elite marathon performance. International Journal of Sports Physiology and Performance. 2013;8(5):573–578.
6. Burke LM, Millet G, Tarnopolsky MA. Nutrition for distance events. Journal of Sports Sciences. 2007;25(S1)–S38.