Marathon Fueling Guidelines

Fueling for 26.2 miles can be an intimidating task. At this distance, it is not just about the preparation of your legs. One must also have a nutrition strategy dialed in. We want to provide some basic guidelines that you can use towards your own fueling strategy. First and foremost, we want to stress this is not a “one-size fits all” explanation of marathon nutrition. You must find what works best for you, and you must have practiced it! Our goal is to help you build your successful path to the finish line.

Leading up to the race

The classic thought of “carbo-loading” is often taken the wrong way. Many people view it as stuffing their face with pasta the night before. A one-time dump of carbs usually doesn’t lead to the happiest gut or most effective use of carbohydrate intake. Two-three days leading up to the race look for ways to increase your carbohydrate intake not necessarily your calorie intake. As you increase your carbohydrate percentage, stick with foods that you know and try to avoid to many high fiber choices in the last two days leading up to the race. Hydration is also more than just a day before job. Make sure that you are putting a strong focus on hydration in all points of training, not just the day prior to racing.

Morning of the race

Capping off your glycogen stores the morning of a race is extraordinarily important. Depending on the sensitivity of your stomach, aim for eating breakfast 2.5-4 hours before race time. Aim for a breakfast rich in carbohydrates and lower in fiber. Keep it simple and something you have practiced with before. Whether that be oats with honey and a banana or a bagel with peanut butter and a sports drink, make sure you know what your stomach has had success with. Keep hydrated, making sure your urine is lighter in color. You can also consume a gel or some of a sports drink prior to the start of a race.

During the race

The human body can only store enough carbohydrates (glycogen) in the liver, blood and muscles for about 20 miles of running, therefore fueling during the race is critical to not “bonk” or hit the dreaded “wall.” Hydration is also a critical aspect to race performance. Hydration helps with absorption of electrolytes and can make sure the muscles are working fluidly.


Studies suggest we need about 45-60g of carbohydrates an hour to fuel properly in the marathon. If you are running closer to a 3 hour marathon, you likely need to be fueling on the higher end of this. If you are in the 4-5 hour range, you can probably opt for the lower end of this amount. Most athletes can benefit from taking in carbohydrates about ~30-45 min depending on what they have trained with. We suggest not taking in all 45-60g in one shot during the hour. Space it out so that you don’t have a sludge of gel in your stomach. It is easier to cap off your energy stores, than to consistently empty them and then completely refuel. Carbohydrates can be consumed in a number of ways. This is where it is highly individual. Your gut is highly teachable. You need to practice your intake at least a few times before race day to ensure you have a plan that will sit well with you. The last thing you want is GI stress on race day because you are winging your fueling plan. You can use a combination of electrolyte drinks and gels to get the fuel you need, it is not necessary to just use one constant source of fuel.

Ideas for fueling sources 

  • 1 energy gel (Hammer, Honey Stinger, Gu, Power Bar, Maurten etc.): 21-25g of carbohydrates (take with 4-8 oz of water)

  • 4-5 energy chews: 16-25g of carbohydrates

  • 8oz of Gatorade or other sports drink ~10g of carbohydrates (Sword, Tailwind, Maurten, Hammer, Skratch, etc.) 


Hydration is a big part of success on race day. Depending on race conditions and sweat rate this is another highly variable component to success. In addition to taking 4-8 oz of fluid with gels or chews, we recommend aiming for a more fluids than just that. Practice hydration in similar conditions to what your race day will be so you have an accurate view on how much fluid you need to be taking in.


Caffeine is one of the most effective performance enhancers. If you drink coffee prior to training runs, there is no reason it cannot be part of your pre-race routine. Coffee not your thing? Many energy gels have caffeinated options that contain about 40-50mg of caffeine. Now we wouldn’t suggest taking only caffeinated gels, but if you want to take one mid-way or three-quarters of the way through your race, you can get a nice pick me up.

Making your fueling plan successful

  • Make sure you have practiced your race day fueling strategy on at least 2-3 long runs.It doesn’t need to be every long run, but you should have a good familiarity with your fuel. 

  • During the race, if you are having some GI stress, do not force your fueling plan. If you feel like you are about to “lose your cookies,” be willing to be adaptable.

  • Don’t try anything new on race day.

  • Make sure you purchase your nutrition a week or two prior to your race. Make sure your local run specialty store or the company your order from has it in stock!

  • Have a plan to carry your nutrition. There is a lot of apparel out there that is comfortable and has pockets or storage galore. There are also fuel belts and water bottles with pouches. Find what is comfortable for you!

  • Want to race as stress free as possible? Look at what fuel sources the race you are doing is handing out at aid stations. Practice with those items.


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Will Christian

I was a 2:27 marathoner that seemed to have hit the ceiling. It seemed that I couldn't break that time. I ran a 2:20 marathon this past fall and a big reason for that success was due to coaching and guidance. Coaching is like having a second set of eyes on a problem.

As an active duty service member we are taught "Attention to Detail." I was focusing on my stronger attributes while neglecting my weaker ones. My personal coach pointed a few things out and changed a few of my workouts and like magic; I smashed my PR in the marathon.