What To Eat Before A Marathon

Fueling an athlete is a balancing act between making sure a runner can make it through a session without running out of energy, and not carrying too much food that causes them to either gain weight or slow down because they have a belly full of oatmeal.

runner holding tummy

There’s a lot said about what to eat before you set out to run, or what to have before a big race or endurance event.

So today we are going to explore all of the nutrition considerations you should make before lacing up your running shoes and heading out the door.

Before we even get to pre-run nutrition, we first need to define why nutrition is so important in the first place, and prepare our bodies for optimal race preparation.

Why Nutrition And Preparation Is Important For Your Endurance Goals

As we’ve already alluded to; running a good race can be made or lost in the kitchen. And without proper dietary considerations, you’ll never be able to make it far (no pun intended.)

The first thing food should do is support a healthy body; which can be difficult to remember when we’re so focused on how we look or how far we can run.

But food is the process of nourishing our bodies so that we feel good and perform at our best. This should always be remembered above all else.

The next part to consider is how heavy the runner is. Generally speaking; a lighter runner is going to be able to perform better because they have less weight to carry around the road, course, or circuit.

Therefore, just force-feeding yourself pasta and potatoes is not always the best strategy.

If a runner is too heavy, however, just cutting food is going to negatively impact performance because less fuel = less energy. So how do you ensure you are at a good weight without losing performance?

You aim for weight loss in the off-season, or early on in the season. This can prevent any performance dips and ensure the runner is of a healthy weight.

This means that a lot of your preparation will be done months out from the marathon.

For those that are already at their race weight; you can simply manage your nutrition by sticking to a diet that keeps you at weight maintenance.

What Foods Should I Eat?

What To Eat Before A Marathon?

To make things as simple as possible, we’ll break foods down into three categories, also known as macronutrients:

  • Proteins (meats, fish, eggs, dairy, and legumes)
  • Carbohydrates (pasta, bread, potatoes, vegetables, rice)
  • Fats (oils, nuts seeds, butter)

From here we need to eat a ratio that is congruent to our goal, as well as our food preferences, meaning that it isn’t one-size-fits-all for every runner.

However, we can generalize and create a template that will fit most runners quite well.


Whilst protein is often synonymous with muscle building and the weights room, it’s still a vital macronutrient as it will help to prepare all of the muscles that break down during a run on the asphalt.

Aim for around 1.2 – 2 grams of protein per pound of body weight per day. For example, if you weigh 170 lbs, you would aim for around 140 – 170 grams of protein per day.

A food tracking app like My Fitness Pal can help you track your protein intake.

Dietary Fat

Next, you should aim to consume healthy fats. Having a good amount of dietary fat in your diet will help to keep your brain sharp, cells in good shape, and aid recovery after exercise.

Fat also helps to slow digestion, therefore keeping you feeling fuller longer and preventing overeating later on. 

A good rule of thumb is to stick to aiming for around 0.5 grams of fat per lb of bodyweight. So our 170 lb athlete should consume around 85 grams of fat.


Lastly, carbohydrates are what give us energy. Contrary to popular belief, carbs do not make you fat. Eating too much food from all the food groups will make you fat.

They are broken down into two types: Simple and Complex Carbohydrates. Simple carbs are found in fruits, refined carbohydrates such as white bread and white pasta, and some vegetables.

These are quickly digested and provide a quick burst of energy. As such, these should be eaten in moderation.

Complex carbs are found in whole grains, beans, lentils, and other starchy foods. They take more time to digest but provide sustained energy throughout the day.

The remainder of your calorie target will be made up of carbohydrates, after calculating your protein and fats, but feel free to make adjustments that suit your food preferences.

Race Day Nutrition 

What To Eat Before A Marathon?

Now that we’ve established general principles for weight and how your diet should look from a macronutrient perspective, it’s time to optimize how to eat on race day.

Your day is best started with a meal that is easy to digest and break down so that you’re not going to be bogged down and bloated throughout your run, as well as keep your blood sugar levels as balanced as possible.

You should select foods that sit well with you that you’ve already tried in previous runs.

Some of the most common meals that work well for many people are foods like a banana, energy bar, or protein smoothie that include oats and fruit. Even a bowl of cereal can be a good option.

Aim to consume this meal at least 1-4 hours before the race. If you eat too close to the race, you may feel weighed down and heavy which will affect performance.

East too far out from the race and you run the risk of feeling hungry which will also affect performance.

For longer races like a marathon, it’s always best to have tried a meal and then go for a long run so you can see what types of meals and how large the meal needs to be so that you aren’t left guessing 4 hours before the timer starts.

You should also consider some supplementation to help boost performance and lower run times.

One of the most commonly used supplements is caffeine which improves mood, focus, and can increase your sports performance.

A cup of coffee with your pre-race meal will help you later on when you complete your marathon.

Another common supplement is beets which are packed with nitrate; which improves mitochondrial preparation and increases blood flow to the muscle.

A few slices included with your pre-race meal could help with your race performance. 

What About Throughout The Run?

Intra-workout nutrition can also be a good idea, especially for long-distance events like a marathon.

As your body depletes its glycogen stores, it will need to top up carbohydrates to maintain a high energy output.

A good rule of thumb is to consume around 60-90 grams of carbohydrates per 60 minutes of activity.

Some of the best ways to get carbohydrates effectively into the body are through energy gels or energy bars that can be carried throughout the race.

Final Thoughts

The important thing is that you do what works best for your body. Going into race day without any trials beforehand can make-or-break your race.

The key to a successful race day is to plan, train consistently, and practice eating properly.

It’s important to remember that there is no one right way to prepare for a marathon, but the above tips should help you get the best possible start.

Megan Rinzel
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