‘What should I eat before a run? This is one of the most common questions we get, especially from beginner runners. And while experienced runners often have their fueling sorted (until they don’t!), we’ve all made mistakes, leading to stomach cramps, nausea, low energy, or a mad dash to the nearest loo.
The truth is: there’s no one-size-fits-all answer. Some runners have iron stomachs while others are more sensitive. Fortunately, while some of this is personal trial and error, there are some general guidelines on what to eat and when, plus key fueling strategies depending on the time and type of your run.
In this blog we will discuss
- Your body’s Energy needs
- How digestion works
- Simple vs Complex Carbohydrates
- What to eat before a morning or evening run
- What to eat before a race
Understanding Your Body's Energy Needs
Your body gets energy primarily from carbohydrates, which are stored as glycogen in your muscles and liver. These stores can fuel you for around 60 minutes. After that, your body turns to fat for energy, a slower, less efficient process. So, if your run is under an hour, you might not need to eat beforehand, especially if you’re an experienced runner. But I often challenge this idea for beginners. Running for more than 30 minutes can feel intimidating for new runners, and starting empty may not be the best idea just yet.
Protein plays a different role. It’s more essential after your run, helping repair microtears in your muscles to build them back up stronger than before.
Understanding what you should eat before a run in terms of providing you with adequate energy for the activity but also avoiding any intestinal issues is important.
The key goals for your nutrition before a run are:
- Top up glycogen stores
- Avoid hunger during the run
- Keep digestion comfortable
- Maintain steady energy
That balance depends on what you eat and when you eat it.
The Digestion Timeline
If we take a quick look at how digestion works, it becomes much clearer why timing meals before a run is so important.
When you eat, food first sits in your stomach, where it’s broken down into a liquid. This stage can take anywhere from about 30 minutes for something light, up to 2–3 hours for a larger or heavier meal. While it’s here, it’s not doing much for your run yet. It’s just being processed. If you head out for a run at this stage you may feel your food sloshing around due to the motion of running. This can lead to nausea or vomiting and in some cases acid reflux.
Food then moves into the small intestine. This is where the important part happens. Carbohydrates are broken down into glucose, absorbed into the bloodstream, and either used immediately or stored as glycogen in your muscles. This is when your food actually becomes usable energy. In terms of running, this is a better location for your food but it is not altogether ideal here either. The problem here is that running pulls blood flow away from your digestive system and toward your working muscles. That’s when you can experience cramping.
Some foods slow everything down because they delay how quickly the stomach empties and can remain in this in the stomach for over 4 hours, so it is best to avoid eating these prior to running:
- Fat – the slowest (fried foods, heavy sauces)
- Protein – moderate (meat, eggs)
- Fibre – slows movement (whole grains, vegetables)
The fastest to process:
- Simple carbohydrates (fruit, white bread, sports drinks)
So when you think about pre-run nutrition, it’s not just about what you eat. It’s about making sure that, by the time you start running, your food has moved past the stomach and into a stage where your body can actually use it and it is not causing you discomfort by sloshing around as you run.
Simple vs Complex Carbohydrates
Just to add more confusion to the question, “what should I eat before a run?”, it helps to know that not all carbohydrates are created equal.
Some take longer to break down but provide a steadier, longer-lasting supply of energy. These are your complex carbohydrates, and they’re often lower on the glycaemic index, meaning they release energy more gradually. Others are processed quickly and give you a more immediate hit of energy. These are your simple carbohydrates, and they tend to be higher on the glycaemic index, so they raise blood sugar more quickly.
Both have a place in your diet as a runner. The key is timing.
If you eat complex, lower GI carbs too close to your run, they’re more likely to still be sitting in your stomach, which can leave you feeling heavy or uncomfortable. Simple, higher GI carbs, on the other hand, are quicker to digest and more useful when you’re eating closer to heading out the door.
So it’s not about choosing one over the other. It’s about using each at the right time so the energy is available when you actually need it.
Simple carbohydrates (like fruit, white toast, honey):
- Break down quickly
- Leave the stomach faster
- Enter the bloodstream sooner
- Can start providing energy within 30–60 minutes
Complex carbohydrates (like oats, whole grains, rice):
- Take longer to break down
- Stay in the stomach longer
- Release energy more gradually
- Typically need 2–3 hours to be fully available
That’s why a banana works 30 minutes before a run, but a bowl of oats needs more time.
What to Eat Before a Morning Run
So now you understand what your body actually needs, how digestion works, and why some carbs give you quick energy while others take their time. The next step is making this practical. What does this actually look like when you’re about to head out for a run?
Morning runs
This is where many runners get it wrong, simply because time is tight. You may feel hungry and low in energy after your overnight fast but unless you get up 1 -2 hours before running, your choices for nutrition are more limited.
If it’s an easy, shorter run, you can go out fasted or alternatively have something small:
- A glass or orange juice
- Half a banana
- A slice of toast & honey
If it’s a longer run or there’s intensity:
- Give yourself at least 30–60 minutes
- Go for quick, simple carbs similar to above.
Fueling for Later Runs
Running later in the day can be more challenging, as you’ve typically consumed several meals and snacks by that point. This means there’s more food in your system to potentially interfere with your run.
It’s important to be aware of which foods might cause you digestive or intestinal discomfort and avoid them until after your workout. Spicy and high-fat foods are common culprits, as they can lead to bloating, cramping, or the dreaded mid-run dash to the toilet.
To stay comfortable and perform well, stick to lighter, easy-to-digest meals in the hours leading up to your run, and save the heavier or richer foods for afterwards.
Good choices for pre-run meals include:
- Chicken and rice
- Pasta and Sauce
- Chicken Panini
If you plan on running before dinner, aim for a small carb rich snack to keep the energy levels up: Banana, sandwich or cereal bar.
A good tip is to keep some runner friendly snacks at work or in your car if you run directly after work for example; cereal bar, pretzels or a sport’s drink.
Nothing New on Race Day!
If you have a race coming up, do not try anything new. Make sure your race-day nutrition is tried and tested. There’s nothing worse than running out of energy mid-course or realizing that your pre-run snack of spicy nuts was a terrible idea.
3–4 hours before:
- A familiar, carb-focused meal
- Low in fat and fibre
Examples:
- Oats & Honey
- Toast with peanut butter and banana
- Rice with something light
60 minutes before (optional):
- A small, simple carb top-up if needed for example a banana energy gel or sports drink
Nothing new, nothing heavy, nothing that sits in your stomach.
What to Eat Before a 5K Race
A 5K is short and fast, so your focus should be on easy-to-digest carbs 1–2 hours before the race. Have a few sugary sweets or candy at the start line if you feel you need a little extra energy.
- White toast with jam
- Banana and peanut butter
- Small bowl of cereal with milk
- A bagel with honey
What to Eat the Night Before a Long Run, Half Marathon or Marathon
The night before a big effort, whether it’s a long run, half marathon, or full marathon, it’s important to top up your carbohydrate stores. However, resist the urge to go overboard. One of the most common mistakes runners make is dramatically increasing portion sizes the night before a race, thinking it will help. Suddenly tripling your usual portion of pasta isn’t a great idea, your body isn’t used to processing that volume and it may backfire with bloating or GI distress.
Instead, treat your running nutrition as an integral part of your training. Just as you prepare your body with long runs and speed work, practice your race-week nutrition strategy during training. Aim to gradually increase your carbohydrate intake over 2–3 days leading up to race day, rather than cramming it into one meal.
There’s nothing worse than weeks of focused training being undone by poor pre-race food choice. For more in-depth guidance on this topic, consult ‘Running Your First Marathon, Made Easy‘, or ‘Marathon Training Strategies’.
Long run fueling options:
- Pasta with marinara and grilled chicken
- White rice with salmon or eggs
- Pizza (keep in plain and simple)
Avoid: spicy food, rich sauces, and anything that’s new to you. If you are travelling to your race, do some research beforehand to determine if you can replicate your tried and tested fueling in the hotel/accommodation.
Keep a Running Journal or Running Log
While there’s no universal formula for perfect nutrition and hydration, there is a formula that works for you. Finding it requires a bit of trial and error, experimenting with what you eat, when you eat, and how your body responds. Remember, what works for someone else may not suit you. The longer you are running, the more you will learn what to avoid and what is ideal. We often learn the hard way but it is a lesson learned and not repeated. Personally, I prefer running first thing in the morning before breakfast, but always after my coffee! If I feel a bit low on energy, I’ll have a banana or carry a gel in my pocket just in case.
Keeping a log of what you eat and when particularly in relation to your running, whether in a physical journal or using an app or online tool, is invaluable. Over time, patterns will emerge, helping you pinpoint foods that give you energy and those that don’t sit well. Imagine standing on the start line of your next race confident that you’ve cracked the code to your personal fueling strategy, that’s the power of knowing what works for you.
I have not discussed hydration as that will be covered in another blog post. However please do consume water regularly. Get into a habit of drinking water throughout the day, every day, not just your running days. It is so important to be well hydrated, for so many reasons, but more about that later.
Need a Bit of Guidance? We Are Here to Help
So when you’re deciding, what should I eat before a run’, think beyond just the food itself. Consider timing, digestion, and how quickly that energy will actually be available to you. You want to start your run feeling light, and fuelled, not weighed down or running on empty. Get this balance right, and your runs will feel smoother and far more enjoyable.
A little planning goes a long way. Think about what you’ll eat and when, choose a route where you’ve got access to facilities if needed, and bring some simple backup fuel like gels or sweets. It doesn’t need to be complicated, but having a plan makes the whole run feel more controlled from the start.
If you’re still figuring out what works best for your body, when to run, what to eat, or how to stay consistent, we are here to help at Achieve Running Club.
Check out our range of running books for more tips and advice:
Running for Beginners https://amzn.to/3Hcqk8P
Beginner Runners Manual https://amzn.to/3IVDlnL
A heart for running https://amzn.to/45wsCJ7
Step up to 10K https://amzn.to/3GVO9li
Running Your First Marathon https://amzn.to/41n8NBy
Marathon Training Strategies https://amzn.to/41n8NBy
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