Why Consistent Fueling Is Critical for Ultrarunning
Ultra-distance running is often described as an 'eating contest with some running mixed in'. The body's carbohydrate (glycogen) stores are limited, providing fuel for only about 90 minutes of high-intensity activity. While ultra events are typically lower intensity, they deplete these stores over many hours, necessitating a constant external fuel source to prevent 'bonking' or hitting the wall. A steady, frequent intake of nutrients is the only way to sustain energy and avoid severe performance drops.
The Importance of Training Your Gut
Just as you train your muscles to endure the mileage, you must train your digestive system to handle fuel during a race. Exercise diverts blood flow away from the stomach toward working muscles, which can inhibit digestion. Regularly practicing your race-day nutrition during long training runs teaches your gut to process fuel efficiently under stress, significantly reducing the risk of gastrointestinal (GI) distress on race day. It is important to experiment with different fuel types—gels, bars, real food—to see what your system tolerates best.
The Golden Rule: Eat Small, Eat Often
Most experts agree that the ideal strategy is to consume small, frequent amounts of food. This method helps to maintain steady energy levels and avoids overwhelming the digestive system with large boluses of food. A good rule of thumb is to set a timer on your watch to remind you to eat or drink. Popular intervals range from 20 to 30 minutes.
- Start your fueling strategy early, ideally within the first 30 minutes of the race, to stay ahead of the energy curve.
- Consider dividing larger energy bars or chews into smaller, timed bites to spread out the intake.
- Use aid stations as a cue, but do not rely solely on them. Carry your own trusted fuel, as aid station options may cause surprises.
Caloric and Macronutrient Targets During an Ultra
General recommendations suggest consuming 150-400 calories per hour during an ultra-marathon, though individual needs vary based on body size, intensity, and duration. Carbohydrates should be the cornerstone of your fueling plan. Many athletes aim for 30-90 grams of carbs per hour, using a mix of glucose and fructose to improve absorption and tolerance.
As the race extends beyond 6-10 hours, incorporating small amounts of protein (5-10 grams per hour) can help with muscle repair and satiety. Some fat can also be beneficial in very long events to provide energy density and combat 'sweet fatigue,' the aversion to sugary foods that often develops over time.
Sample Fueling Strategy: A Comparison
To illustrate a personalized approach, here is a comparison of two potential fueling strategies for an ultra-runner. Both should be practiced extensively during training.
| Strategy Element | Option A (Primarily Liquid/Fast Carbs) | Option B (Mixed Fuel) |
|---|---|---|
| Fueling Schedule | Every 20 minutes | Every 30 minutes |
| Carbohydrate Target | 60-90 grams per hour | 50-70 grams per hour |
| Fuel Sources (0-4 hrs) | Energy gels, sports drinks, chews | Gels, sports drink, fruit, energy bars |
| Fuel Sources (4-10+ hrs) | Sports drinks, liquid calories (e.g., flat soda, soup) | Mix of sweet (gels, chews) and savory (salted nuts, potato chips, broth) |
| Electrolytes | Found in sports drinks and electrolyte tabs | Included in sports drink, salty food, or separate tabs |
| Taste Fatigue Management | Focus on variety of sweet flavors | Mix of sweet, savory, and umami tastes |
| Protein/Fat Inclusion | Minimal or from specialized liquid fuels | Small amounts from solid foods like nut butter, jerky after 6+ hours |
Mastering Hydration and Electrolytes
Adequate fluid intake is inseparable from a successful fueling plan. The body requires water to digest food, and proper hydration prevents a decline in performance. Aim for 400-800 ml of fluid per hour, with regular sips every 10-20 minutes, adjusting for temperature and sweat rate. Electrolytes, particularly sodium, are vital to replace what is lost through sweat. A minimum of 500 mg of sodium per liter of fluid is generally recommended, although some athletes may need more. Using a sports drink or adding electrolyte tabs to water can help achieve this balance.
Dealing with Race-Day Challenges
Even with the best plan, ultra-marathons present challenges like GI issues, appetite loss, and flavor fatigue. Being flexible and prepared to adapt is crucial. If solid food becomes unappealing, switch to liquid calories like sports drinks, juice, or broth. If GI distress hits, slow down your pace and try easily digestible options like simple sugars or ginger-based products. Having a plan B and C is the hallmark of an experienced ultrarunner.
Conclusion
The question of how often should you eat during ultra-distance events is best answered with a strategy of frequent, small, and consistent intake. By training your gut, planning macronutrient balance, diversifying your fuel sources, and staying on top of hydration and electrolytes, you can minimize performance drops and maximize your chances of a successful finish. The precise frequency and quantity will depend on your individual body and the race conditions, making thorough experimentation during training essential. Learn more about ultramarathon nutrition from the International Society of Sports Nutrition.
