What To Eat the Day Before a Marathon

Male athlete energized by the marathon runner diet is ahead of his competitors during a road race marathon

Training for a big race and wondering what to eat the day before a marathon? Nutrition is half the battle, and making sure you're getting all the nutrients and minerals your body needs will help you stay healthy and perform at your best. 

But what does a well-balanced diet mean for a marathon runner? And what should you do the day before a marathon to improve your endurance, recovery, and overall performance?

In this article, we’ll take an in-depth look at nutrition for runners - and exactly how to fuel your body before a marathon. 

Before we talk about how much (and what) to eat the day before a marathon, let’s discuss one of the most important nutritional practices before a marathon: carb-loading. 

How to carb-load before a marathon

Carb-loading is a popular marathon runner diet practice for runners trying to maximize their energy levels. It involves increasing your intake of carbohydrates in the days leading up to the race.

Carb-loading is definitely worth considering when you’re thinking about what to eat the day before a marathon.

With so many different opinions out there for carb-loading, it can be tough to know what to eat the day before a marathon. But here are a few general tips to keep in mind when carb-loading:

Start carb-loading a few days before the race

Don't try to cram all of your carbs into one meal the night before the marathon. Your body needs time to digest and store all of those extra calories, so start carb-loading a few days in advance.

Gradually increase your intake of carbohydrates over the course of a few days leading up to the marathon.

Focus on complex carbs

When looking at what to eat the day before a marathon, steer clear of simple carbs.

Simple sugars might give you a quick burst of energy, but they will also cause your blood sugar to spike and then crash. And no one wants to be crashing during a marathon! 

Complex carbs, like whole grains and vegetables, are a better choice for sustained energy during a long race.

Don't overdo it

You might be tempted to eat more than usual when carb-loading, but resist the urge. When you’re planning what to eat the day before a marathon, make sure you don’t plan on eating too much. Doing this can lead to stomach cramps and other digestive issues on race day.

So what should you eat? And how many calories should you aim for? Let’s discuss what to eat the day before a marathon.

What to eat the day before a marathon

It's important to fuel your body properly before a big race. Knowing what to eat the day before a marathon can make a massive difference in how you feel on race day. 

Here's a look at what you should (and shouldn't) eat before running 26.2 miles.

What to eat for breakfast

When looking at what to eat the day before a marathon, the first meal we need to discuss is breakfast. 

Whether or not you choose to go for a “shakeout run”, you should keep your breakfast light and carb-focused. A good rule of thumb is to eat about 300 calories for breakfast on the day before your marathon.

Some good breakfast ideas include whole-grain toast with jam, banana with peanut butter, or a granola bar. 

What to eat for lunch and dinner before a marathon

The next part of what to eat the day before a marathon is, of course, lunch and dinner. 

You'll want to eat a bigger lunch and dinner the day before the marathon, but you don't need to go overboard. Pasta is a popular choice when thinking about what to eat the day before a marathon, because it's packed with complex carbohydrates, which are a great source of energy.

You might be tempted to load up on protein for your marathon runner diet, but that's not necessary. Stick to complex carbs and moderate amounts of fat for the best performance on race day.

When thinking about what to eat the day before a marathon, don’t forget salt. It’s vital for proper fluid balance in the body, and it's especially crucial for runners. That's because salt can help to prevent dehydration and cramping.

Some runners like to eat extra salt the day before a marathon to help ensure they're properly hydrated. This isn't necessary for everyone, but if you think you might be at risk for dehydration or cramping, it's worth a try. Just don't have too much - too much salt can actually lead to dehydration.

Now we’ve fully covered what to eat the day before a marathon, let’s take a look at what you should drink.

It's vital to stay hydrated in the days leading up to the marathon, but you don't want to drink too much. Drinking too much water leads to hyponatremia, which is a condition caused by low sodium levels in the blood. Symptoms of hyponatremia include headaches, nausea, vomiting, and confusion.

To avoid hyponatremia, drink plenty of fluids in the days leading up to the marathon, but don't go overboard. Stick to water or sports drinks and absolutely avoid alcohol. 

You should also not drink any caffeine on race day, as it can lead to dehydration.

What to eat on the day of a marathon

Now we’ve covered what to eat the day before a marathon, let’s turn to what to eat on race day

Eating a big meal before the race can weigh you down and make you feel sluggish. It’s best to eat a light breakfast or lunch that is easy to digest, such as toast with honey or a banana.

Some runners like to have a little snack an hour or so before the race to give them a boost of energy. This could be something like an energy bar, or a handful of nuts, or a liquid protein shot. 

Just as you should stay hydrated in the days leading up to the marathon, you should drink water regularly on the day of the race itself.

It is also important to wear comfortable clothes and shoes on race day. You should be able to move freely and not have any chafing or rubbing. In the days leading up to the marathon, practice running in your race day outfit to make sure everything fits well and doesn't bother you.

Marathon day is an exciting day! Just make sure you are prepared by following these tips on what to eat and drink to ensure you have the best chance of achieving your peak performance. 

Of course, you can eat perfectly, and still be taken out by an inopportune injury before (or on) race day. Luckily, there are some simple habits and supplements you can take to help you perform your best and avoid unfortunate accidents. 

How to prevent an injury before a marathon

The worst thing that could happen for someone before a marathon is suffering an injury. 

Weeks, months, or even years of training - followed by not being able to compete in the event you have worked so hard towards - can be absolutely spirit-crushing. This is why it is so important to make sure you practice injury prevention in the period leading up to the marathon.

One of the best ways to prevent an injury before a marathon is to cross-train. This means incorporating other types of workouts into your training regiment in order to build overall strength and avoid overuse injuries. 

Swimming, biking, and elliptical training are all great forms of cross-training that can help improve your running performance while also decreasing your risk of injury.

Another important way to prevent injuries is to make sure you are properly stretching and foam rolling. These activities help to release any tightness or tension in your muscles that could lead to an injury. It is important to do both static and dynamic stretching, as well as foam rolling, on a regular basis.

You should make sure you listen to your body and take rest days when needed. Overtraining can lead to injuries, so it is crucial to give your body the time it needs to recover. If you are feeling any pain or discomfort, take a few days off from running until the pain subsides.

Last, but certainly not least, there are supplements you can take to boost performance and assist in injury prevention. Let’s take a look at some of these powerful supplements. 

Supplements to take before a marathon

The best supplements for endurance athletes can make all the difference in your marathon performance and overall health. Here are our favorite supplements for marathon runners:


Minerals such as iron, zinc, and copper are essential for runners, as they help to transport oxygen to the muscles and support energy production. 

Iron is especially important for women, as they tend to be more prone to iron-deficiency anemia.

Protein powder 

When thinking about what to eat the day before a marathon, consider protein powder. It is one of the best supplements for marathon runners, as it helps to repair and rebuild muscle tissue after training. 

Look out for a protein powder that contains all the essential amino acids, and try to find a hydrolyzed protein from a reputable company to ensure the best absorption.

Also keep in mind the many whey protein powders can cause a “too much protein stomach ache” for some athletes. 


Glutamine is an amino acid that you should consider when looking at what to eat the day before a marathon. It’s important for immune function, gut health, and muscle recovery. It's especially beneficial for runners, as it can help to reduce inflammation and speed up the repair of damaged muscle tissue.

Fish oil

Fish is a great food to consider when choosing what to eat the day before a marathon, and fish oil can be even better! Fish oil is a rich source of omega-3 fatty acids, which are essential for maintaining good health. 

Omega-3 fatty acids have anti-inflammatory properties that can help to reduce joint pain and stiffness. They're also important for brain health, so they can help you stay focused and mentally sharp during long runs.


Probiotics are beneficial bacteria that reside in the gut and support digestive health. They can also help to boost the immune system. This makes them a great inclusion for your marathon runner diet, as they can help stave off sickness before race day. 

Look for a probiotic supplement that contains a variety of different strains of bacteria to get the most benefits.


Electrolytes are minerals such as sodium, potassium, and magnesium that are essential for proper fluid balance in the body. They're especially good supplements for marathon runners, as they can help to prevent dehydration and cramping. 

Make sure you're getting enough electrolytes by drinking plenty of fluids and eating foods that are rich in these minerals.

Liquid protein shots 

While protein powder might do the job after training, carrying a bulky protein shake around the race course will distract you and slow you down. That’s why liquid protein shots are one of the best supplements for marathon runners. 

Liquid protein shots come in read-to-drink packets and offer you a whopping 15g of protein. Perfect for giving you that cutting edge in your race. Because they are light and mess-free to consume, they are easy to take mid-race for a little extra boost of energy.

Liquid collagen protein for marathon success

Understanding what to eat the day before a marathon and on marathon day itself can have a huge impact on your performance on race day, and liquid collagen protein can make or break your big event. 

Collagen protein not only provides you with much-needed energy during your race, it is also directly used by your body to heal your joints and muscle tissues. 

This means that regularly supplementing with collagen before race day may help with injury prevention and reducing your recovery times. That’s a lot of benefits from one small supplement! 

Frog Fuel liquid collagen comes in easy-to-use single-serve packets that you don’t need to mix with anything. You can take them leading up to your marathon, and even put a few in your pocket to toss back mid-race. 

Nano-hydrolyzed for easy digestion, this is one protein that won’t slow you down on the race course: providing you with the power and protection you need to perform your very best. 

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