Fueling For A Marathon: A Dietitian’s Guide

Maybe you have running a marathon on your list of New Year’s Resolutions, or perhaps you’re a seasoned runner planning out your races for the upcoming year. But knowing how to properly fuel for a marathon can be tricky business, regardless of your level of experience. Proper nutrition fueling can be the difference between a pleasant race and a painful one. 

The Importance of Proper Fueling

Fueling adequately for a race and during your training is crucial to maintaining good health while doing something that can be incredibly taxing on your body. Making sure your body is taking in proper nutrients can make sure your energy levels stay balanced during a long race or training run, help you avoid the GI discomfort that can crop up during runs, support optimal recovery for after your run, and help prevent injury. 

Goals for Fueling Well

The goal for marathon fueling is to allow you to run your race or long run safely and successfully, whatever that means for you—and avoid hitting the dreaded “wall.” Hitting “the wall” happens when our muscles run out of their glycogen stores. A sharp decrease in performance and increase in fatigue follows. You may feel like you can’t go on any longer. Plus, improper fueling can lead to low blood sugar and possible GI upset.

How a Dietitian Can Help You With Your Marathon Fueling Plan

The good news—while running the race is entirely up to you, when it comes to planning your marathon nutrition and training plan, you’re not alone. A registered dietitian can help you come up with a completely tailored marathon nutrition plan that can take you from your training period, to race day, all the way through proper recovery. The plan may include benchmarks for protein, calories, and fat to hit each day, as well as a nutrition plan and snack or meal ideas for proper pre-and post-workout fueling. By understanding your body and the symptoms or issues that might come up for you (your history of GI problems, or that achilles injury you recently recovered from, for example) your RD can create a plan that addresses your distinct needs. 

Why Fueling Matters During Marathon Training

While training for a marathon, it’s important to test and commit to the nutrition and training plan you’ve worked on with your RD, so that you can see how your body reacts, and make tweaks as needed. Keeping a run diary to track how you felt, and what you ate before and after, can be really helpful in understanding how a certain food or amount of food worked with your body. By testing a nutrition training plan, you’re also training your body to accept food while exercising which can help delay running out of glycogen stores in your muscles. You can always tell your RD if something’s not feeling right, and they can help you make any tweaks needed to your carbohydrate intake or other aspect of your training plan. Once you head into marathon race day, the goal is to know that you’re fueled in the best way for your body, so there won’t be any surprises. 

Pre-Run Fueling: Start Strong

Ok, it’s the morning of your run. Time for race day fueling! You’re up early, and last night you had a nutrient-rich dinner. Even if your nerves are making you feel not-hungry, it’s important to eat breakfast. If you have the time, and it’s between 2-3 hours before your race, eat a balanced breakfast, like toast with peanut butter and banana, or egg on toast. If it’s closer to your race, and you only have an hour, the goal is to eat simple carbs that will be easy to digest. A piece of fruit, dry cereal, oatmeal, or a piece of toast with nut butter are all great options that will add to your energy supply without making you feel full or sluggish.

During the Run: Sustaining Energy

You’re doing it! You’re a few miles in, staying calm, staying on pace. You’ve got this! Now, it’s time to make sure you’re keeping your energy levels up so you don’t end up in a deficit and hit that dreaded “wall.” Once you’ve been running for about 45 minutes to an hour, start to fuel with around ~30g of carbohydrate every half-hour. Most races have fueling stations where they’ll hand out a sports drink, energy gel or banana—but it’s best to stock up with your own! Simple carbs and sugars are best to avoid GI upset. Pretzels, crackers, candy, energy gel, energy bars or gummies, granola bars, dried or fresh fruit, and even applesauce pouches are all great sources of energy for you during a race.

Post-Run Fueling: Optimize Recovery

You did it! You crossed the finish line, and now it’s time to celebrate, or take a long nap. But what you put in your body now matters. Post-race fueling helps avoid injury and promotes optimal recovery. You’ll likely still be sore and tired, but proper nutrition can make this period more bearable and less…well, painful. Within an hour after you run, eat a balanced meal with between 20-30 grams of protein. This could look like a turkey and cheese sandwich on whole wheat bread with a glass of milk and fruit on the side, or a delicious grain bowl with protein, complex carbohydrate and a healthy fat. 

Hydration and Electrolytes

With all of this emphasis on food and nutrition, don’t forget to hydrate! Aim to get a minimum of 64oz of water per day, spread throughout the day. And you can replenish with electrolytes as needed! This is especially important if you’re running in hot weather. Skratch Labs, Liquid IV, and sports drinks like Gatorade, Powerade, and Pedialyte are all great options! Keep in mind glucose and electrolytes work together. Sugar helps your body absorb electrolytes, ensuring you get the most out of your electrolyte consumption. When marathon training, it is typically recommended to choose electrolytes with sugar for optimal electrolyte replenishment.

Marathon Training Fueling Guide

Need a quick refresher on optimal baseline nutrient information for your marathon training journey? You can save this infographic for easy reference. 

Get tailored support from a Culina Health RD

Are you looking for nutrition advice on fueling for a marathon, or simply how to eat to feel more energized throughout the day? Our diverse team of registered dietitians can help with this, and more. We are in-network with most major insurance companies and are licensed to see patients in all 50 states! Get matched with a Culina Health registered dietitian today.