Avoid hitting the wall and prevent stomach cramps by eating the right foods.

Eating the wrong foods before your long run may cause cramps, side stitches, or general digestive/stomach discomfort. Get it completely wrong, and you may have to detour to find the nearest bathroom.

For a lot of your training, you won’t necessarily need to plan your pre-run nutrition. In fact, you may even enjoy running in a fasted state. But you’ll want to top up your glycogen stores for a little extra energy for your weekly long run. After all, you’ll likely be running for upwards of 1 hour.

As you may have discovered in the past, what works for someone else might not work for you when it comes to your pre-run nutrition. One runner may eat a small bowl of porridge and a slice of toast, while the same meal would upset your stomach. It’s about finding what works best for you!

This blog post explains what to eat before a long run. We’ll also touch on what foods to avoid, how long to eat before running, and a little on hydration.

What should I eat before a long run?

Ideally, you should eat foods with a low glycemic index. These cause your blood sugar to rise and fall much more steadily vs. foods high in sugar that cause blood sugar spikes.

Low glycemic foods typically contain more fibre, minerals, and other essential nutrients. 

What you eat before your long run depends on what time of day you’re running. 

If you’re running in the morning, you may choose a bowl of oatmeal. If you’re running in the afternoon, you may have breakfast and a light lunch consisting of wholegrain toast and eggs. 

Avoid trying anything new before your run — it’s not the time to try clams for the first time!

What to eat the night before a long run?

As well as eating the day of your long run, you should stock up on carbs the evening before. These shouldn’t make up your entire meal — but a good portion should be carbs.

It’s best not to overthink it. Stick to foods you regularly eat and avoid excess fibre. Quality carbs include pasta, potatoes, and rice. 

Ensure that you eat some quality protein, too, such as chicken, steak, eggs, salmon, or seafood. Healthy fats may include olive oil, butter, cheese, avocado, and nuts.

Example evening meals the night before your long run may include:

  • A baked potato, vegetables, and a steak
  • Sweet potato, vegetables, and salmon
  • Pasta, chicken breast, and vegetables
  • Homemade pizza with chicken and peppers 

Over time, you’ll find what works best for you (and what foods you may wish to avoid). 

What to eat before a long run in the morning?

You may find it difficult to eat before your long run in the morning, especially if you’re an early riser up at dawn runner. But even a small meal will top up your glycogen stores to provide you the energy you need for your long run.

The same guidelines apply: stick to foods not too high in fibre and that have a low glycemic index to prevent stomach upset.

Below you’ll find some example breakfasts you can eat before your long run:

  • A bowl of oatmeal with a banana and a tablespoon of nut butter
  • A couple of slices of toast with a piece of fruit 
  • 2 bagels with your favourite toppings (banana, peanut butter, etc.)

Experiment with it and find what works for you. This is also great practice to find your ideal pre-race meals.

What NOT to eat before a long run 

As you may have found out the hard way, there are also plenty of foods you should avoid before a long run (or any type of exercise). Typically, these include foods that are high in fibre and have a high glycemic index.

Eating these foods may cause gastrointestinal upset during your run. 

You should also avoid spicy foods, sugary drinks and sweets (these will cause your blood sugar to spike), and fried foods. 

Stick to what you regularly eat, and you should be fine (granted what you usually eat isn’t the above!).  

What about hydration?

Okay, now you know what to eat before your long run, what about hydration?

Proper hydration improves sports performance, decreases recovery time, and helps regulate your body temperature (this is extremely important when training in hot weather). 

As a general rule of thumb, aim to consume a minimum of 1.5 to 2 litres of water a day. If you’re training, drink more. You typically won’t need to drink during your run unless it’s upwards of 1 hour. Instead, you hydrate before and after training.

But for your long run, if it’s longer than 1 hour you might need to top up your fluids to prevent performance decline and dehydration risks. Drink little and often and aim for 0.5 litres of water every hour as a starting point. You can adjust this as needed to best suit your hydration needs.

To learn more about hydration, you can read our why is hydration important in sport blog post.

Don’t forget to eat during your run!

If your long run is longer than 1 hour and certainly more than 90 minutes, you’ll want to get in some extra carbohydrates to prevent you from bonking (this is where you muscles run out of fuel, also known as “hitting the wall”).

Aim to eat 30-60g of carbs per 1 hour. That’s one BAR50 or 1-2 GEL30s per hour. Eat before you're hungry, and adapt your nutrition as needed depending on how long you’re running for.


What to eat before a sprint race?

A snack 1-2 hours before a sprint may include a couple of bagels with peanut butter, a small bowl of porridge, or a couple of slices of toast. Avoid eating a full meal beforehand as this will sit in your stomach.

What not to eat the night before a long run?

Avoid spicy foods, foods too high in fibre, excess fat, and anything too salty (as this may cause dehydration). 

Can I eat 20 minutes before running?

Try to eat your last meal 1-3 hours before running. You can eat a small snack up to 30 minutes before running but try not to eat anything too heavy before you head out the door.

What should I eat before a 10 mile run?

You may choose to eat a bowl of porridge with your favourite toppings, a couple of slices of toast and a banana, or a smoothie bowl.