The Nutritional Foundation of an Ultra Runner
Successful ultra running is built on a solid nutritional foundation, and for long distances, this foundation hinges on a balanced intake of carbohydrates, protein, and fat. While carbohydrates are the primary fuel source, especially at higher intensities, the lower, more relaxed pace of many ultra events allows for greater reliance on fat as a secondary energy source. Protein plays a crucial role not as fuel, but in preserving muscle mass and aiding recovery. The strategy is a continuous, calculated process, not just about what is eaten during the race.
Carbohydrate: The Primary Fuel Source
When running for hours, the body relies on stored carbohydrates (glycogen) and fat for energy. However, glycogen stores are limited and can be depleted within 90 minutes of high-intensity effort. For ultra runners, constant carbohydrate intake is essential to keep glycogen topped up and prevent hitting the dreaded 'wall' or 'bonk'. A common recommendation is to consume 60-90 grams of carbohydrates per hour, though advanced runners can train their gut to tolerate higher amounts, sometimes up to 120 grams per hour, by using dual-transport blends of glucose and fructose. This intake must be met consistently, even when appetite wanes.
Protein for Muscle Repair and Satiety
While not a primary fuel, protein is vital for ultra runners. The eccentric loading and muscle damage sustained during long, demanding runs necessitate a consistent supply of protein to aid repair and recovery. A small intake of 5-10 grams of protein per hour during a race lasting more than 12 hours can help reduce muscle breakdown. This can be achieved through protein-fortified foods or drinks. Post-race, a 4:1 ratio of carbohydrates to protein is recommended within the recovery window to accelerate glycogen replenishment and muscle repair.
The Strategic Use of Fat
In ultra events lasting many hours, especially at lower intensities, fat becomes a more significant fuel source. Fat is calorie-dense, providing more energy per gram, which is useful for minimizing pack weight in self-supported races. Successful finishers of 100-mile races have been shown to consume five times more fat than non-finishers, suggesting a greater tolerance and reliance on fat during prolonged efforts. Savory, high-fat foods can also combat palate fatigue that often accompanies sugary sports nutrition.
The Tactical Art of In-Race Fueling
Eating during an ultramarathon is a skill that must be honed in training. It involves more than just consuming calories; it's about timing, variety, and listening to your body.
The Critical Role of Hydration and Electrolytes
Proper hydration is paramount, as dehydration significantly impairs digestion and overall performance. Ultra runners need to drink regularly and often, aiming for 450-750 mL of fluid per hour, adjusted for conditions. Consuming electrolytes, especially sodium, is equally important to maintain fluid balance and prevent cramping and hyponatremia, a dangerous condition caused by low blood sodium levels. Elite Trail Team recommends 500-1000 mg of sodium per litre of fluid in hot or humid conditions.
Combating Palate Fatigue with Variety
One of the biggest challenges in ultra running is "flavor fatigue" or the loss of appetite for sweet, sugary gels after hours of running. To combat this, ultra runners learn to rotate their fuel sources, introducing a variety of tastes and textures. What sounds good at the beginning of a race might be unpalatable 10 hours later. Savory and salty options become appealing, as do real foods with more substance.
Common Fuel Options for Ultra Runners
- Sports Gels and Chews: Quick, concentrated energy source. Easily portable but can contribute to palate fatigue. Must be taken with water.
- Liquid Carbs/Sports Drinks: Provide both fuel and hydration. Useful for runners who struggle with solids. Need to be balanced with water to avoid GI distress.
- Real Food (Sweet): Bananas, dried fruit, rice cakes, and candy bars are simple and provide sustained energy.
- Real Food (Savory): Boiled potatoes, sandwiches (PB&J or savory), crackers, and miso soup offer a satisfying, salty alternative.
Gut Training: The Digestive Adaptation
For many, gastrointestinal (GI) distress is the primary reason for a 'Did Not Finish' (DNF). To prevent this, ultra runners train their gut just as they train their muscles. This involves gradually increasing carbohydrate intake during long training runs to teach the digestive system to tolerate fueling while exercising. The golden rule of "nothing new on race day" is a direct result of this practice, ensuring that a runner's stomach is familiar with every product and meal they consume during the race itself.
Pre-Race and Recovery Nutrition
What happens before and after the race is just as important as the in-race nutrition strategy.
Carbohydrate Loading for Max Glycogen
Starting a race with full glycogen stores is a huge advantage. Ultra runners begin carb-loading 24-48 hours before the event, aiming for 10-12 grams of carbohydrates per kilogram of bodyweight. This is done by increasing intake of easy-to-digest carbs like pasta, rice, and bread while reducing fiber to minimize GI discomfort. A final carb-rich breakfast 2-4 hours before the race tops off the liver glycogen stores depleted overnight.
The Importance of Post-Race Recovery
Nutrition doesn't stop at the finish line. The first 30-60 minutes post-race are crucial for replenishing glycogen and beginning muscle repair. This recovery window is often used for consuming a carb-and-protein-rich meal or drink, though it doesn't need to be perfect. After an ultra, eating is a priority. In the days that follow, a balanced diet with plenty of carbs, protein, and healthy fats is key to a faster recovery.
Comparison of Ultra-Running Fueling Options
| Feature | Energy Gels/Chews | Liquid Carbs/Sports Drinks | Real Food (e.g., potatoes, sandwiches) |
|---|---|---|---|
| Carb Source | Simple, fast-absorbing sugars. Often glucose/fructose blend. | Simple and complex carb mixes. Also contains electrolytes. | Mix of simple and complex carbs, some protein/fat. |
| Absorption Speed | Very fast; provides quick energy boost. | Fast to moderate, depending on osmolarity. | Slower; requires more digestion effort. |
| GI Comfort | Can cause distress if not taken with enough water or if overused. | Can cause bloating if too concentrated or used exclusively. | Generally well-tolerated, especially at lower intensities. |
| Palatability | Can lead to flavor fatigue over many hours. | Can also cause sweet fatigue. | Offers variety and satisfies savory/salty cravings. |
| Weight & Portability | Extremely lightweight and easy to carry in large quantities. | Carries hydration but can be bulky. | Can be heavier and less convenient, especially for self-supported segments. |
The Ultimate Conclusion: Practice and Adapt
The key to unlocking peak ultra-endurance performance lies in a highly personalized and well-practiced nutritional strategy. While there are evidence-based recommendations, such as targeting 60-90g of carbohydrates per hour and maintaining hydration with electrolytes, individual tolerance and race specifics dictate the final plan. Listen to your body, train your gut, diversify your fuel to fight flavor fatigue, and never introduce new products on race day. The journey to mastering how ultra runners eat is a continuous process of learning and adaptation, ultimately rewarding those who pay meticulous attention to their fueling needs.
For further reading on advanced fueling protocols and metabolic efficiency strategies, check out this guide.
