When running a marathon or a half-marathon, in addition to proper training preparation, nutrition plays a key role in your performance.
In terms of nutrition before, during, and after a marathon, it comes down to three essential nutritional strategies.
In this blog, you'll learn all you need to know about proper nutrition for a running marathon.
What to eat before a marathon?
Before a marathon you should eat plenty of fast carbohydrates. This nutritional strategy is called carb-loading. It's goal is to fill up your glycogen stores as much as possible before the marathon.
There are plenty of different approaches you can take to your carb-loading strategy, but we believe, as also confirmed by the renowned nutritionist Dr. Tim Podlogar, that a 1-day carb-loading strategy should be enough.
When carb loading, there a few things to keep in mind:
- Consume a high quantity of fast carbohydrates, such as white rice, white pasta, white bread, or even gummy bears.
- Avoid fats because they will only increase your caloric intake without additionally filling your glycogen stores.
- Avoid dietary fibers because they will burden your digestive tract and potentially cause problems during the marathon.
- Do not train during the day before the marathon, as doing so will deplete the glycogen stores you want to fill.
- On the other hand, Dr. Tim Podlogar recommends a fasted training session before you begin to carb load.
If you follow these tips, you should be fine. But if you want a detailed guide with specific meal examples, you can find it here.
Before a marathon, you should eat plenty of fast carbohydrates to fill up your glycogen stores.
What to eat during a marathon?
The nutritional strategy used during a marathon is called fueling. Fueling is about providing fast carbohydrates to your body as an external source of energy. The goal is to slow down glycogen consumption.
You can find more about fueling here, but here are a few quick tips:
- Simple sugars work best, as they get quickly absorbed in your system, which is exactly what you need during a marathon.
- Optimal is a combination of glucose and fructose, preferably in the 1:0.8 ratio, considered best by scientific research.
- Do not forget about hydration. To properly hydrate, you must consume water and the correct concentration of minerals.
- Before you attempt any fueling strategy at a marathon, be sure to prepare your digestive system and test it during training.
Want to find the best energy gel for you? Check out or top recommendations!
Marathon nutrition goals
Before we look at our specific recommendations on what to eat during a marathon and a half-marathon, let's look at your nutrition goals.
There are three things you need to consume during a marathon:
- Minerals aka electrolytes
In terms of carbohydrates, it makes the most sense to talk about your hourly intake, as the length of your marathon may vary greatly.
Top-level runners consume up to 90 grams of carbohydrates per hour (in extreme case even more). But this is a very high intake that requires both physical preparation and gut training.
For most athletes, consuming anywhere from 45 to 60 grams per hour should be sufficient. Depending on the brand you use, this equals roughly to 1 serving of an isotonic sports drink and 1 to 2 energy gels.
Also, depending on your carb-loading strategy, we recommend consuming 1 energy gel within 30 minutes before the marathon.
With that in mind, let's look at what exactly you should consume during a marathon and a half-marathon.
What to eat during a marathon?
A marathon is a very intense endurance event that will likely fully deplete your glycogen stores, so you need to take care of proper sports nutrition.
Consume 1 serving of an isotonic sports drink per hour. This represents 26 grams of carbohydrates.
Consume 4 to 6 energy gels distributed throughout the marathon. An energy gel contains 22 grams of carbohydrates, so in total this represents from 88 to 132 grams of carbohydrates.
If your strategy is to consume 60 grams of carbohydrates per hour and your estimated time is 3:30 hours, you need to intake 210 grams of carbohydrates in total.
Carbohydrate intake chart
|Isotonic sports drink||3||78 grams|
|Energy gel||4 to 6||88 to 132 grams|
|Total:||166 to 210 grams|
Since 60 grams of carbohydrates per hour is a reasonably high intake, you don't need to consume the full 6 energy gels. Our recommendation is to consume 5 energy gels, one each at the following intervals:
- 1:05 h
- 1:40 h
- 2:10 h
- 2:40 h
- 3:10 h
If your estimated time is 4:00 h, add one energy gel at 3:40 h. If your estimated time is 3:00 h, you only need to consume 4 energy gels.
Also keep in mind that these values are expressed for 4Energy Gel and Iso Drink, which also applies to most isotonic sports drinks and energy gels, but not all of them.
For instance, Nduranz's supplements are created for top-level athletes and contain double the amount of carbohydrates, so keep that in mind if you use Nduranz products.
What to eat during a half-marathon?
Unlike the marathon, a half-marathon will not fully deplete your glycogen stores. For this reason, you don't need to consume nearly as many carbohydrates.
We still recommend you consume 1 serving of an isotonic sports drink per hour and 1 to 2 energy gels throughout the half-marathon.
If your estimated time is 1:30 h, consume 1,5 serving of an isotonic drink and an energy gel at the 1:05 h mark.
If your estimated time is 2:00 h, consume 2 servings of an isotonic drink (one per hour) and 2 energy gels at the 1:05 h and 1:35 h marks.
If you are well prepared, you might even attempt to finish the half-marathon without consuming energy gels at all.
What to eat after a marathon?
After any intense exercise, your body needs the following nutrients within 30 minutes:
- Carbohydrates to refill glycogen stores
- Protein to rebuild muscle tissues
- Minerals to allow your body to rehydrate
Additional tips for running nutrition
Now you know what to eat before, during, and after a marathon or a half-marathon, but there's more to sports nutrition than that.
Taking good care of your body at all times is vital if you want to preserve and improve your running performance, and this will definitely reflect in your results at the marathon.
As a runner, taking care of your immune system is extremely important, as this will allow you to avoid illness and injury, which in turn allows you to train and progress consistently.
One of the most important factors related to your immune system is stress, something runners experience a lot of. For this reason, you should definitely keep your stress levels in check.
One of the ways athletes manage their stress levels is by using adaptogens, such as ashwagandha. And if you are under stress because your expectations before the marathon, check out the tips from our sports psychologist.
Finally, there's this thing called VO2 max. VO2 max can greatly impact your performance at the marathon, but luckily, there are ways to increase it. The best way is to follow a well-structured plan and support it with the correct dietary supplements.
It's important that you keep a strong immune system, which also means you must learn how to manage stress caused by intense running sessions.
Taking care of proper nutrition for a running marathon requires you to use the three essential nutritional strategies: carb-loading, fueling, and muscle recovery.
During a marathon, you should aim to consume 1 isotonic sports drink per hour and 4 to 6 energy gels distributed throughout the event.
During a half-marathon, you should still consume 1 isotonic sports drink per hour and 1 to 2 energy gels throughout the event, depending on your estimated time.
Before you attempt any fueling strategy, be sure to test it in training to avoid digestive issues during the marathon.
To sustain your long-term athletic performance, take care of your immune system, learn to manage stress levels, and consider improving your VO2 max.