The Core Principles of Ultramarathon Fueling
Fuelling an ultramarathon is a complex physiological puzzle, demanding a consistent energy supply to avoid performance crashes known as 'bonking'. The fundamental goal is to manage your carbohydrate stores, which are limited, while efficiently utilizing your much larger fat reserves. The longer the race, the more crucial a well-practiced nutrition strategy becomes for success.
Prioritizing Carbohydrates
Carbohydrates are the body's primary and most efficient energy source during high-intensity exercise. For ultra-endurance events, experts recommend consuming between 60 to 90 grams of carbohydrates per hour, a rate that modern sports nutrition, often utilizing multiple transportable carbs like glucose and fructose, makes possible.
- Start early and consistently: Begin fueling within the first 30 minutes of the race, even if you don't feel hungry, to keep your energy tank topped up.
- Utilize multiple carb types: A 2:1 ratio of glucose to fructose is often used in modern sports products to maximize absorption and minimize gastrointestinal (GI) distress.
- Tailor your intake: Individual needs vary based on body size, intensity, and temperature. Practice in training to find your personal hourly target.
The Importance of Electrolytes and Hydration
Proper hydration and electrolyte balance are just as vital as calorie intake. Sweat loss can lead to imbalances, especially in sodium, affecting muscle and nerve function. Dehydration impairs performance and can lead to GI issues.
- Drink regularly, not just to thirst: Aim for 400-800ml of fluid per hour, with small, frequent sips to prevent stomach sloshing and aid absorption.
- Include sodium: Replenish sodium lost through sweat via sports drinks, salt tabs, or salty foods. A typical target is 500-700 mg of sodium per liter of fluid, though 'salty sweaters' may need more.
- Consider all-in-one fuels: Products like Tailwind, which combine carbohydrates and electrolytes, can simplify your fueling and hydration plan.
Real Food vs. Engineered Products: A Comparison
While sports products offer convenience and fast-absorbing energy, taste fatigue and a craving for savory food are common during long ultras. Incorporating a mix of real food can be a game-changer for maintaining consistent intake.
| Feature | Sports Products (Gels, Chews, Drinks) | Real Food (PB&J, Potatoes, Broth) |
|---|---|---|
| Convenience | Highly portable, easy to carry and consume quickly. | Requires more preparation and can be messier to eat on the move. |
| Digestibility | Engineered for rapid absorption; use multiple carb types to ease digestion. | Slower digestion due to fiber, fat, and protein content. |
| Palatability | Limited flavor options can cause taste fatigue over long distances. | Offers a wide variety of sweet, salty, and savory tastes. |
| Energy Type | Primarily simple carbohydrates for fast energy boosts. | Provides a mix of carbs, fats, and protein for more sustained energy. |
| Typical Use | Ideal for higher intensity sections or quick energy needs. | Excellent for slower, longer stretches, especially in the later stages. |
Training Your Gut for the Race
Your digestive system needs training just as much as your muscles. Practicing your race-day fueling plan during your long training runs is essential for avoiding GI issues and identifying what works for your body.
- Simulate race conditions: Practice your exact fueling and hydration plan during your longest training runs. If you're racing in the heat, train in the heat to see how your body reacts.
- Start with lower carb intake: If you're new to high hourly carbohydrate loads, begin with a lower target (e.g., 40-60g/hr) and gradually increase it to let your stomach adapt.
- Experiment with variety: Test different types of sports products and real foods during training. Your preferences will change during the race, and having a list of tested options is invaluable.
- Listen to your body: Learn the difference between simple cravings and true GI distress. Use familiar foods and backup options when your primary plan becomes unappealing.
Conclusion
Effective fueling during an ultra is a practiced skill, not a natural instinct. By strategically consuming a blend of carbohydrates, maintaining precise hydration and electrolyte balance, and training your gut to tolerate race-day nutrition, you can significantly enhance your performance and overall race experience. Practice your plan meticulously, stay flexible, and remember that consistent, early fueling is the key to conquering the long miles ahead. For a deeper scientific dive into endurance fueling, consider exploring the resources at mysportscience.com.
The Race Day Fueling Checklist
Pre-Race
- Pre-load glycogen stores: In the 2-3 days before the race, increase carbohydrate intake while reducing fat and fiber to stock up on energy and minimize GI issues.
- Morning fuel: Eat a light, carb-rich breakfast 2-3 hours before the start to top off energy reserves.
- Final top-off: A final, smaller carbohydrate snack (e.g., a gel) and 200-300ml of fluid can be taken 15-30 minutes before the start.
During the Race
- Start early: Begin your hourly feeding and drinking schedule from the start of the race, not when you feel hungry.
- Rotate fuel types: Alternate between sweet gels/chews and savory real foods to combat taste fatigue, which is common in events over 6 hours.
- Take a break to eat solids: Use slower sections or aid stations to consume real food, allowing for easier digestion without the jostling of running.
- Use caffeine strategically: If you use caffeine, introduce it later in the race to combat fatigue, rather than relying on it from the start.
Post-Race
- Recover immediately: Consume a carb and protein-rich snack or drink (e.g., chocolate milk) within 30-60 minutes after finishing to begin recovery.
- Rehydrate: Continue to drink fluids and electrolytes to replace sweat losses and aid muscle repair.
- Listen to cravings: Your body often tells you what it needs to recover, whether it's salty snacks or simple sugars.
Troubleshooting During the Race
- Stomach issues: Slow down, use simpler calories (like baby food pouches), and consider warm broth or ginger chews to settle your stomach.
- Hitting the wall: If you bonk, switch to easily digestible carbohydrates like gels or sugary drinks (e.g., flat cola) for a quick energy boost.
- Cramping: In addition to maintaining electrolytes, some runners find relief from a shot of pickle juice due to its effect on the nervous system.
Conclusion
Successful ultramarathon fueling requires practice, flexibility, and a deep understanding of your body's individual needs. By training your gut, varying your fuel sources, and staying on top of hydration, you can set yourself up for a stronger, more enjoyable race. Remember, the journey to the finish line is a collaboration between your physical training and your nutritional strategy.
