How to Fuel Your First Ultra Marathon: A Practical Framework
- Rebecca
- Apr 1
- 4 min read
A beginner-friendly guide to fuelling your first ultra marathon — including what to eat, when to eat, and how to build a simple plan.
Fuelling tends to get more complicated than it needs to when people move into ultras. Partly because the races are longer. Partly because there’s a lot of conflicting advice often taken from very different contexts and applied as if it’s universal.
So you end up with questions like:
How much should I be eating each hour?
Do I need to rely on gels?
What happens when I can’t face eating at all?
Let me say from the outset that there is no single “correct” way to fuel any event, including ultras. However, there are some principles that make things work better.
I use the PACE framework as a simple way of organising those key principles.
The goal of ultra fuelling (keep it simple)
It doesn’t matter how hard you try, or how well-structured your plan is, your energy intake will not match your energy expenditure in an ultra.
So the aim is to slow the rate at which that gap widens, so that energy levels, pacing, and decision-making remain as stable as they can.
In practical terms, that usually comes down to avoiding long periods where you’re not eating or drinking.
A reasonable starting point
For a first ultra, it’s really useful to have something simple to anchor to. I use these four principles:
eat at regular intervals
drink regularly
start early, rather than waiting until you feel you need it
aim somewhere in the region of 200–300 kcal per hour
You’ll see that there aren’t many targets, no guidelines on what you should eat or how much to drink. The goal is simply to consistently fuel your body while you’re moving.
You can adjust it once you’ve got some experience.
A simple framework for ultra marathon fuelling: the PACE framework
To keep things organised without turning it into a spreadsheet exercise, I tend to use four headings:
Plan – Adapt – Condition – Execute
They’re not steps so much as things to keep in mind throughout training and racing.
Plan: Build your basic ultra fuelling strategy
A plan needs to hold up when you’re tired, not just when you’re sitting at home thinking it through.
At a minimum you need to:
have a rough idea of how much you’ll aim to eat each hour
decide what that looks like in actual food
have an alternative if you can’t stomach your first choice
For example, an hour might look like:
a bar or similar carbohydrate source
something additional (fruit, small savoury items)
fluids with electrolytes
The detail matters less than whether you’ve actually used it before. The saying “don’t try anything new on race day” extends to your nutrition.
Adapt: make changes early
In an ultra you are on your feet for a long time and things change. It could be your pace, the temperature, your appetite, or all three. The skill is noticing that early enough to respond while it’s still manageable.
For example:
if you start to feel slightly nauseous, it often helps to ease the intensity and switch to fluids for a period
if it’s warmer than expected, you might need more fluids and electrolytes
if food isn’t appealing, smaller amounts more frequently can be easier to manage
Waiting until you have stopped eating and drinking tends to make pulling it back harder.
Condition: practise fuelling in training
Eating while running isn’t something most people are used to but it improves with practice.
Use your long runs to practise:
eating at regular intervals
trying different foods
gradually increasing intake
This isn’t just about avoiding stomach issues. It’s also about improving how reliably you can take in and use fuel under load. It doesn’t need to be aggressive. Consistency is the key.
Execute: keep things ticking over
This is usually where things can fail. Not because the plan is wrong, but because:
eating becomes less appealing
you get distracted by the trail or chatting with your fellow runners
gaps between intake get longer without being noticed
A simple structure helps:
eat to a schedule rather than appetite
keep alternative options available
avoid letting long gaps develop
Once your intake drops off significantly, it’s really difficult to bring things back quickly.
When to do when things go wrong
It’s common for fuelling to drop off at some point. Nausea, loss of appetite, or just general fatigue can all interfere with your plan.
The most important thing is that you notice that and try to find a solution to get things back on track. That could be by:
reducing intensity for a period
prioritising fluids
reintroducing small amounts of food once things settle
Putting it all together
PACE is just a way of keeping attention on the parts that make the biggest difference:
having something workable to start from
adjusting it as conditions change
practising fuelling in training
maintaining some consistency during the race
For a first ultra, that’s usually enough structure.
If you want to map this out
Some runners find it useful to write this down in advance. Not in detail, but enough to answer:
what am I likely to eat each hour?
when will I eat?
what’s the alternative if that stops working?
I’ve put together a simple one-page PACE fuelling framework to make it easier for you to plan and execute. If you want to turn this into a simple race plan, you can download the PACE planner here.
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