What to Eat Before Your Marathon, According to an RD

It’s a fact many marathoners face, your nutrition is almost just as important as the running itself. This marathon season, I’ve had new runners and experienced runners ask me, what should I eat before my marathon?

This question came especially as their corrals for big races like the New York City Marathon were released—with much later start times than their training long runs.

women eating on tailgate of car — Your marathon is only as good as your carb loading. Nail your nutrition strategy NOW.

So, I got with registered sports dietitian Megan Robinson to go over what to eat before your marathon, including the day before, night before, and morning of—with varying start times.

Related: How I Fueled by 2:54 Marathon

Because what you eat before your marathon could literally make or break your race and undo your hard work. The success of long-distance running hinges on how much fuel you have in your tank to cover the distance. Give your body the wrong fuel or wrong amount, and it could be game over for your marathon goals.

So, in this article, I am going to cover the when, why, what, and how of what to eat before your marathon, including:

Why you should eat before your marathon
When should you eat before your marathon
What to eat before your marathon, including the day, night, and morning before
How to eat before your marathon
The factors that affect what you eat before your marathon, and
Sample pre-race breakfasts

Let’s get going!

Why should you eat before your marathon?

You need to eat before a marathon or any endurance event because your body needs fuel to run. The primary source of fuel (energy) for running is glycogen (carbohydrates). So, the goal of eating before a marathon is to stock your glycogen stores so they can give you the fuel you need to keep running.

What makes marathons tricky is that our bodies can only store about 500 grams of glycogen in your muscles and 80 grams in your liver which means we run out of our fuel stores within two hours of running. Every human on the planet except one will take longer than two hours to complete a marathon.

If you don’t have enough glycogen (or glucose) for your marathon, your body won’t have enough energy to get to the finish line. It will then prefer to use fat for fuel as its primary fuel source which takes much longer to convert to energy, requiring you to slow your pace. This is called bonking, or hitting the wall.

Related: How to Avoid the Wall in the Marathon

How eating carbs prevents hitting the wall in the marathon

what to eat before your marathon pin — Pin these tips for what to eat before your marathon according to a dietitian for later!

When you bonk or hit the wall in a marathon, it feels like you are running through quicksand. It takes a lot more effort to run a slower pace than it would if your body was taping into glycogen to run.

Therefore, eating carbohydrates that are stored as glycogen in your muscles and liver in the week leading up to your marathon and on race day morning gives you the fuel you need to burn, including for that last 10k.

If you want to do well running a marathon, you should consider carb loading up to a week before and top of those glycogen stores the morning of your race. (Exception is for those on a low-carb diet). A study in Nutrition Reviews supports “glycogen supercompensation results from a combination of ample rest, reduced training volume, and the consumption of a high-carbohydrate diet.” (Learn more about tapering here).

When should you eat before a marathon?

Ideally, you eat your main meal (or breakfast) 3-4 hours before the marathon, and then a carb-based snack an hour before, says Robinson. This allows your body enough time to digest your food the morning of the marathon.

If that requires you to wake up too early race morning, at the very least, you should eat your breakfast two hours before the marathon. Some elites have been known to wake up to eat, then go back to sleep before their race.

Planning out your pre-race meal can be tricky if you have an especially early or late start time, as many running major marathons do.

Related: How to Train Your Gut

**Below is when to eat before your marathon based on your start time:**

7 a.m. start time: Eat by 5 a.m. Take an energy gel 15 minutes before you get to the start line. If you eat at 4 a.m. Eat a snack at 6 a.m.
8 a.m. start time: Eat at 5 a.m. Eat a snack at 7 a.m. Take a gel 15 minutes before.
9 a.m. start time: Eat at 5 a.m. Snack at 8 a.m. Gel 15 minute before.
10 a.m. start time; 6 a.m. breakfast. Snack at 9 a.m. Gel 15 minutes before.
11 a.m. start time: breakfast at 7 a.m. Snack at 10 a.m. Gel 15 minutes before you line up on the starting line.
12 p.m. start time: breakfast at 8 a.m. Snack at 11 a.m. Gel 15 minutes before you line up.

Related: 6 Best Energy Gels for Runners

What should I eat before my marathon?

Runners want to eat about 150-200 g of carbohydrates with a little bit of protein and healthy fats before a marathon about 3-4 hours before their race. Then eat a smaller snack of about 50-70 grams of carbohydrates about 60-90 minutes before the race starts.

According to Robinson, here is what that might look like for a runner with an 8 a.m. race start:

5 am: 1st breakfast. Aim for 150-200 grams of carbs (more if you weigh more, read below). You can sip on the high carb beverage over the span of several hours and coffee or tea that you normally drink before race day.
7 a.m.: 2nd breakfast. Eat about 50-70 grans of carbs. Stop eating 30 minutes before race time.
7:45 a.m.: Last thing to do is to take an energy gel to top your glycogen stores.

*You can adjust this timeline to fit your race so that:

1^st breakfast is 3-4 hours before your race time.
2^nd breakfast (snack) is 60-90 minutes before your race time.
Energy gel is about 15 minutes before the gun goes off.

Related: How to Start Running: A Complete Guide

What to eat before a marathon

Now you know when to eat before a marathon. Now, here are ideas of what to eat before a marathon.

Your pre-race breakfast should be:

carb-loading-guide — Here is your carb loading guide for a marathon.

High in simple carbohydrates
Low in fat, protein, fiber, acid and grease to avoid taxing the digestive system
Familiar and something you have practiced before

Here are some pre-marathon breakfast ideas (1^st breakfast—150-200 g carbs) from Robinson:

What to eat 3-4 hours before the race

Large deli plain bagel (60 g carb) + 2 T peanut butter (8 g carb) + medium banana (25 g carb) + 1 T honey (15 g carb) + high carb sports drink like High Carb Skratch (100 g carb) or Maurten 320 Mix (80 g carb)= 180-200 g carb
Oatmeal: 1/2 cup raw oats (30 g carb) prepared with 1 cup milk (12 g carb) + 1/4 cup raisins (30 g carb) + 1 T honey (15 g carb) + 1 medium banana (25 g carb) + 1 T PB (4 g carb) + high carb sports drink (80-100 g carb) = 200-220 g carb

Here are some pre-race snack (2^nd breakfast – 50-70 g carbs) ideas:

What to eat 60-90 minutes before the race

2 fig bars (40 g carb) + sports drink (20 g carb- like Skratch or Gatorade)
1 1/2 to 2 ounces of pretzels (30-40 g carb) + sports drink
1/2 plain bagel (30 g carb) with 1 T jam (15 g carb)= 45 g carb + sports drink
A banana (27g) with a sports drink (35g)
Two Honey Stinger waffles (42 g) with sports drink (35 g)

*you don’t need to eat this all at once but stop eating 30 minutes before race time

What should I eat the day before my marathon?

Aim to eat a total of 8 to 10 grams of carbs per kilogram of weight the day before your marathon. Eat the majority of these carbs at lunch.

Example: So, let’s say you weigh 140 pounds, that’s 63.5 kg. Let’s aim in the middle to get about 10 g carbs/kg. That’s 650 carb grams.

Lunch the day before your marathon: Eat about 150-250 g of carbs.
Dinner the night before your marathon: Eat about 50-150 g of carbs.
Pin these marathon breakfast tips for later!
Bedtime snack the night before your marathon is a good idea: Eat about 50 g of carbs (see list of pre-race snacks)

I share a complete guide with carb loading meal ideas in my Carb Load Guide here.

Related: 20+ Snacks for Runners

Is pizza good the night before a race?

You can eat pizza before a marathon but go light on the cheese and avoid meats like pepperoni and sausage. Also, dot the grease off. It’s best to go with a Margherita pizza with fresh mozzarella slices, tomatoes, and basil. Bonus points if the crust is whole grains. Do not over eat the pizza! Or else you may feel sluggish the morning of your race. Not good!

Should I eat pasta the night before a race?

You can eat pasta the night before your marathon, but aim to keep it light on the sauces, oils, and cheese. Salt your pasta, too! And don’t eat too much. Add some vegetables and lean protein to make it an ideal pre-marathon meal, says Robinson.

Should I drink Gatorade before a marathon?

You can drink Gatorade before a marathon as it has electrolytes and carbohydrates, what runners need. Drinking a sports drink the night before and morning of a marathon is a great way to top off your glycogen stores, advises Robinson.

There are a lot of sports drinks on the market. I review sports drinks for runners here.

What foods should marathon runners avoid?

Runners should avoid eating foods high in fat, protein, grease, sugar, spices, and fiber before running, or contain sorbitol. Also avoid eating anything out of the ordinary, warns Robinson.

Related: What to Eat Before You Run

Factors Affecting What to Eat Before Your Marathon

These are general guidelines. Certain factors such as body weight, pace, weather, and time you eat affect your breakfast before a marathon. Here is a closer look at these factors.

Bodyweight

The more you weigh, the more carbs you need for your marathon.

marathon morning nutrition tips IG post — How many carbs you need to eat depends on factors such as your weight, pace, weather, and time you eat.

You want to eat 2-4 grams of carbohydrates per kg of bodyweight race morning, says Robinson. Therefore, the more you weigh, the more you eat.

Example: Back to our 140 lb runner. That means, she will want to eat around 200-250 g of carbs the morning before her race, including her snack. She can eat on the upper end of the ratio if she eats earlier (4 hours before her race, then top off with a snack).

Time You Eat

The earlier you eat, the more you can eat.

If you eat:

Two hours before race time, aim for 2 grams of carbs per kilogram of weight.
Three hours before race time, 3g/kg of weight.
Four hours before race time, 4g/kg.

Weather

If it is going to be extra hot or cold (warmer than 60 degrees or colder than 30 degrees Fahrenheit, you will want to eat on the upper end of your carbohydrate intake ratio as your body will be working extra hard to regulate your temperature. You will likely be running longer as well. Be sure to take in extra electrolytes and salt your food.

See my full Hydration Guide for Runners here.

Pace

The slower you run your marathon, the more carbs you need. Therefore, slower runners need to aim to get up early and eat the upper end of their carb intake ratio.

Related: 18 Healthy Meals for Runners

What to Eat Before Your Marathon Quick Hits

The earlier you eat, the more you can eat which is fuel in your tank.
The more you weigh, the more carbs you need to eat.
The slower you run, the more carbs you need.
If it is really hot or cold, eat more carbs and drink more electrolytes.
Don’t overeat or else you may still be digesting food when you start running. That can upset your stomach.
Leave AT LEAST two hours for your food to digest to avoid stomach issues race day morning.
Avoid eating foods that are hard to digest such as high-protein, high-fat, and high-fiber foods because they can delay stomach emptying and cause gas, bloating and diarrhea.
Carry a water bottle around with you to ensure you are drinking lots of water and are hydrated. Carbs help your body hold onto more water to ensure you don’t dehydrate race day.
Eat simple rather than complex carbs that easily convert to energy such as white rice, breads, bagels, energy bars, or low-fiber cereals.
Don’t eat a lot of protein or fat to allow for more space for carbs.
Eat familiar foods. Don’t eat anything you haven’t practiced with during your long training runs. (Pack your race day breakfast if staying out of town.)
Aim for 8 to 10 grams of carbs per kilogram of weight.
Eat the most carbs at lunch the day before your race.
Eat a small carb snack the night before your race like some graham crackers.
Aim for small meals or snacks often.
Sports drinks and tart cherry juice can help you get to your carb intake goal.
Double-down on hydration with water and sports drinks.
Your plate will look like half carbohydrates, a quarter protein, and quarter vegetables.
Remember what you eat after the race is important too. Replenish with carbs, protein, and healthy fats and keep it up the next day to recover faster.

Giving intentional thought to your nutrition strategy will pay dividends on the big day. I hope this helps!

If you want guidance with your running goals, check out my run coaching services. Also, be sure to check out my free training plans: