Your 50km Fueling Plan: Before, During, and After
Crossing the finish line of a 50-kilometer ultra-marathon requires more than just physical training; it demands a meticulous and well-rehearsed fueling strategy. A common mistake is to underestimate the metabolic demands of such a prolonged effort, which can lead to a drastic drop in performance, often called 'hitting the wall' or 'bonking'. With a thoughtful plan covering the days before the race, the race itself, and the post-race recovery, you can provide your body with the energy it needs to succeed.
The Days Leading Up to Your 50km Race
Effective race-day fueling begins in the days prior to the event. This is the time for carbohydrate loading, a process designed to maximize your muscle glycogen stores, which are your body's primary fuel source for endurance events.
- Carbohydrate Loading: For 36-48 hours before the race, increase your carbohydrate intake to 8-12 grams per kilogram of body weight per day. This can be achieved by focusing meals on complex carbs like rice, oats, pasta, and potatoes. Crucially, as you increase carbs, slightly reduce your fat and protein intake to keep total calorie counts from skyrocketing and to avoid digestive stress. For example, a 70kg runner would aim for 560-840g of carbs daily in the final two days before the race.
- Hydration: Start hydrating several days in advance. Don't wait until race morning to play catch-up. Aim for 2-3 liters of fluid per day and consider adding electrolytes, especially if training in hot or humid conditions. The color of your urine should be a pale yellow.
- Last Dinner: The evening before the race, consume a balanced, familiar, and low-fiber meal. Avoid anything heavy, spicy, or high in fat that might cause gastrointestinal issues. Pasta with a simple tomato sauce or a baked potato with lean protein are excellent choices.
- Morning Meal: 2-3 hours before the start, have a light, carbohydrate-rich breakfast. Stick with what you've practiced in training. Good examples include oatmeal with fruit, a banana, or toast with jam. Limit fat and fiber to prevent stomach discomfort.
Fueling During the 50km Race
During the race, your fueling needs will differ depending on your pace, intensity, and the course conditions. The goal is to provide a consistent supply of carbohydrates to your working muscles and maintain proper hydration without overwhelming your digestive system.
- Start Early: Begin fueling within the first 30-45 minutes of the race. Don't wait until you feel hungry or low on energy, as it's often too late by then.
- Consistent Carbohydrate Intake: Aim for 30-60 grams of carbohydrates per hour. Some experienced ultra-athletes can train their gut to tolerate up to 90+ grams per hour, but start with a lower amount and test what works for you in training.
- Listen to Your Gut: Over the course of several hours, consuming a constant stream of sweet gels or chews can lead to "taste fatigue" and a loss of appetite. Incorporate a variety of flavors and fuel sources, including some solid, savory foods like salted potatoes, pretzels, or a peanut butter and jam sandwich.
- Hydration and Electrolytes: Drink to thirst, but aim for a consistent fluid intake of roughly 400-800ml per hour, adjusting for weather and sweat rate. Ensure your fluids contain electrolytes, especially sodium, to replace what is lost in sweat and prevent hyponatremia. Electrolyte tablets or sports drinks are effective options.
Post-Race Recovery
The work doesn't stop when you cross the finish line. Proper post-race nutrition is crucial for jump-starting the recovery process.
- The 30-60 Minute Window: Your body is primed to absorb nutrients within 30-60 minutes after finishing. Aim for a recovery snack with a 3:1 or 4:1 ratio of carbohydrates to protein to replenish glycogen stores and initiate muscle repair. Chocolate milk, a protein shake, or a banana with peanut butter are excellent choices.
- Rehydrate: Continue sipping fluids and electrolytes for several hours to replace sweat losses and restore hydration. Drinking 1.5 liters of fluid for every kilogram of body weight lost during the race is a good guideline.
- Balanced Meal: Within a few hours, have a larger, balanced meal containing carbs, protein, and fats. A post-race meal like a chicken wrap with cheese and salad or pasta with vegetables and protein will continue the recovery process.
Comparison Table: Race Fuel Types
| Fuel Type | Pros | Cons | Best Used For |
|---|---|---|---|
| Energy Gels | Quick, concentrated carbs; easy to carry. | Can cause stomach distress; limited flavor variety leads to taste fatigue. | Consistent, hourly fueling, especially at higher intensities. |
| Energy Chews/Blocks | Solid texture offers mental break from gels; easy to portion. | Requires more chewing and digestion than gels; can melt in heat. | Mixing up fuel types; steady energy boosts. |
| Sports Drinks | Covers hydration, electrolytes, and carbs simultaneously. | Can be too sweet; some may prefer to control carb/electrolyte intake separately. | Convenient, all-in-one fueling and hydration. |
| Real Food (e.g., Potatoes, PB&J) | More satisfying; savory options combat taste fatigue. | Harder to chew and digest at higher intensities; less portable. | Slower, lower intensity sections; later stages of the race. |
Conclusion
A successful 50km ultramarathon is a holistic endeavor, with proper nutrition being just as important as the physical miles you put in. By practicing your fueling and hydration plan during training, you can build confidence and train your gut to handle the demands of race day. A simple, consistent strategy—focusing on topping off glycogen stores before the race, consuming steady carbohydrates and electrolytes during the run, and refueling promptly after—will help you avoid pitfalls like bonking and finish your race feeling strong and recovered. What works best is highly individual, so take the time to test and tailor your approach to your unique body and racing conditions.
Train your gut to handle fuel during long runs and find your optimal strategy.
