Introduction:
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.
But before you start, have you considered whether you’ve adequately trained your gut and planned your nutrition and hydration? Many runners overlook these critical aspects, which can significantly impact their performance and overall marathon experience. Here are some essential tips to optimize your marathon journey from a sports dietitian’s perspective.
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
During long distance runs and races, it is important to know what works best for your body in terms of fueling. It is very normal and expected for your digestive tract to become more sensitive to food and fuel while you’re running, as your body is trying to run as efficiently and optimally as possible.
Think about it this way – during prehistoric times, running was a way for our ancestors to escape danger, so their bodies weren’t prioritizing digesting any food that they may have eaten. Our nervous systems now tend to respond to running in the same way, which is why training the gut to optimize digestion while running is so important.
If you don’t train your gut to handle carbohydrates during your marathon training, you could risk energy shortages, digestive issues (like cramping, bloating, nausea and even diarrhea), and suboptimal performance leading to slower pace and race times.
How Do You Prepare Your Gut for This?
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.
What About Carb Loading? Does it Actually Make a Difference?
Carb loading, or carbohydrate loading, is a strategy used to maximize glycogen stores before an endurance event. This involves increasing carbohydrate intake while tapering training in the days leading up to the race. The goal is to enhance glycogen reserves beyond typical levels, which can delay the onset of fatigue and improve performance.
Example of a Carb Load
A typical carb-loading plan might look like this:
- 2-3 Days Before the Race: Increase carbohydrate intake to about 8-12 grams per kilogram of body weight per day. Focus on high-carb, low-fiber foods to minimize gastrointestinal discomfort.
- Meals:
- Breakfast: Oatmeal with banana and honey.
- Lunch: Pasta with marinara sauce and a side of bread.
- Dinner: Rice with grilled chicken and steamed vegetables.
- Snacks: Energy bars, fruit, and sports drinks.
The Science Behind Carb Loading
Carb loading works by increasing the amount of glycogen stored in your muscles and liver. When glycogen stores are maximized, your body has a larger reserve of energy available during prolonged exercise. This strategy has been best shown to improve endurance and delay the onset of fatigue, allowing you to perform at a higher level for longer periods. Carb loads tend to be most recommended for endurance events lasting longer than 1.5h.
The Importance of Hydration
Alongside carbohydrates, hydration and electrolyte replacement are crucial during a marathon for several reasons:
- Maintaining Fluid Balance: During a marathon, you lose a significant amount of water through sweat. If you don’t replace that fluid, you can become dehydrated, leading to fatigue, cramps, and a decrease in performance. Severe dehydration can even cause dizziness, confusion, and heat exhaustion.
- Preventing Electrolyte Imbalance: Along with water, sweat also contains electrolytes, especially sodium, potassium, and magnesium. These minerals are vital for muscle function, nerve signaling, and maintaining the balance of fluids in your body. If electrolytes aren’t replenished, you may experience muscle cramps, weakness, and even more serious issues like hyponatremia (low sodium levels in the blood), which can be dangerous.
- Sustaining Energy Levels: Proper hydration helps deliver oxygen and nutrients to your muscles. When you’re dehydrated, your blood volume decreases, making your heart work harder to pump blood. This leads to early fatigue and can slow your pace.
- Preventing Overheating: Water also helps regulate body temperature. As you run, especially in warmer conditions, your body heats up. Without adequate hydration, your body struggles to cool itself through sweating, which can lead to heat stroke or heat exhaustion.
Hydration and Electrolyte Tips:
- Begin hydrating within the first 15 minutes of your race and consume fluids regularly throughout.
- Replace electrolytes with sports drinks or electrolyte tablets to prevent imbalances.
- Pay attention to your body’s signals—thirst, dry mouth, or muscle cramps may indicate dehydration or electrolyte loss.
Balancing water intake and electrolytes is key to staying strong and finishing your marathon safely.
Conclusion
Nutrition and hydration are critical components 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@soomanutrition.com or by phone at (202) 738-4726. You can also book an appointment with one of our professionals directly by clicking this link.
