There’s nothing quite like the thrill of crossing the finish line of a marathon. Those 42.2 kilometers can feel like living 10 different lives—each kilometer a new chapter filled with highs and lows. As you stand at the start line, a mixture of nerves, excitement, and confidence surges through you, accompanied by immense pride in the training you've committed to over your training season.
The Importance of Carbohydrates
What Do Carbohydrates Do in the Body?
Carbohydrates are your primary and preferred fuel source for endurance activities, including marathon running. When consumed, carbohydrates are broken down into glucose, which is used for immediate energy or stored as glycogen in the muscles and liver.
During prolonged exercise, your body relies heavily on these glycogen stores. As your glycogen levels deplete, you begin to experience fatigue and reduced performance, commonly referred to as “hitting the wall.”
How Your Body Uses Energy During Long Runs
During long runs, your body utilizes a mix of fuel sources—carbohydrates, fats, and, to a lesser extent, proteins. The proportion of each fuel source used depends on the intensity and duration of the exercise.
When it comes to marathons, carbohydrates are initially the predominant fuel source. As the run continues and glycogen stores diminish, the body increasingly shifts to using fat stores for energy if we do not fuel during the race.
With that, although our bodies can find energy through a different fuel source, performance can decline significantly, highlighting the importance of adequate carbohydrate intake for endurance athletes.
Training Your Gut for Carbohydrate Absorption
To prepare your gut for carbohydrate intake during endurance events, it’s essential to practice your nutrition strategy during training sessions. This process, known as “gut training,” helps the digestive system adapt to higher carbohydrate intakes and reduces the risk of gastrointestinal discomfort during competitions.
Steps for Gut Training
Start Slow: Begin with small amounts of carbohydrates during shorter training sessions and gradually increase the amount over time.
Consistency: Regularly practice consuming carbohydrates during long runs to condition your gut.
Variety: Experiment with different carbohydrate sources (e.g., gels, drinks, chews) to find what works best for you.
Hydration: Ensure adequate hydration, as it aids in the digestion and absorption of carbohydrates.
Recommendations for Fueling During Long Runs and Endurance Events
As a preliminary to fueling for marathons, it’s important that your day-to-day eating supports your daily needs. You want to make sure that you’re eating regularly throughout the day, in a way that supports you throughout all parts of your day, like work or school, training, household chores, taking care of the kids, etc. If you’re unsure of what this would look like for you, definitely get in touch to consult one of our sports dietitians for help!
When you are eating adequately for your training, you will, on average, burn through your glucose and glycogen stores within 1-1.5h of running. For this reason, it is recommended to consume around 30-60 grams of carbohydrates per hour (depending on the intensity of the activity) and start fueling early on into your run or race (ex. within the first 15-20 minutes) to start replacing energy used as early as possible.
For ultra-endurance events lasting longer than 2.5 hours, the recommendation increases to 90 grams of carbohydrates per hour. This can be achieved through a combination of sports drinks, gels, chews, and other easily digestible carbohydrate sources.
What Does This Actually Look Like in Practice?
Here are some practical examples to illustrate effective fueling:
- Gatorade: A standard 12-ounce serving of Gatorade contains about 21 grams of carbohydrates. Consuming a 24-ounce bottle every hour provides approximately 42 grams of carbohydrates.
- Energy Gels: Most energy gels contain about 20-25 grams of carbohydrates per packet. Consuming two to three gels per hour can provide 40-75 grams of carbohydrates.
- Chews and Bars: Products like Clif Bloks or GU Chews typically contain around 20-25 grams of carbohydrates per serving. Combining these with sports drinks and gels can help meet the carbohydrate needs.
Conclusion
Nutrition is a critical component that can make a significant difference in your marathon performance.
Proper carbohydrate intake, hydration and effective gut training can help you maintain energy levels, prevent early fatigue, and enhance your overall race experience.
Working with a sports dietitian can provide personalized guidance to ensure that your nutrition strategy aligns with your training and race goals. By focusing on these aspects, you can ensure that the countless hours you dedicate to training are truly paying off on race day. Remember, a well-nourished athlete is a successful athlete, so make sure your marathon preparation includes a comprehensive plan for fueling and hydration.
To get support with your fueling plan, contact us at info@fuelingforrecovery.com or by phone at (202) 738-4726. You can also book an appointment with one of our professionals directly by clicking this link.
