Your Ultimate 48-Hour Ultra Marathon Nutrition Plan
Proper fueling in the final 48 hours leading up to an ultra marathon is just as critical as your long training runs. This is the prime time to top off your body's glycogen stores—the primary fuel source for sustained endurance events. The goal is to consume a high-carbohydrate, low-fiber diet that is easily digestible and avoids any last-minute surprises on the course. For most athletes, this means aiming for 8–12 grams of carbohydrates per kilogram of body weight per day. For a 70kg runner, that's 560-840 grams of carbs daily, a significant increase that requires careful planning.
The Importance of Low-Fiber Carb Loading
While high-fiber, complex carbohydrates like whole grains are great for everyday health, they can cause digestive upset when consumed in large quantities before a race. Two days out, shift your focus to easily processed, low-fiber carbohydrate sources. This minimizes the risk of bloating and unwelcome mid-race bathroom stops. Examples include white pasta, white rice, peeled potatoes, and white bread. Spreading your intake across multiple smaller meals and snacks throughout the day, rather than three huge ones, can also aid digestion and prevent that heavy, bloated feeling.
What to Include in Your Pre-Ultra Diet
- Breakfast: A familiar breakfast is key. Opt for oatmeal with honey and a banana, a white bagel with jam, or low-fiber cereal with a sprinkle of sugar. Avoid adding too many high-fiber berries or nuts. A smoothie made with fruit juice, a banana, and a small amount of low-fiber protein powder is also an excellent, easily digestible option.
- Lunch & Dinner: Build your main meals around simple starches. Think pasta with a light, tomato-based sauce, white rice with a lean protein like chicken or fish, or baked potatoes without the skin. Keep sauces simple and avoid heavy, creamy or oily options. Small, steamed vegetables like peeled carrots are acceptable, but limit raw vegetables and legumes.
- Snacks: Frequent, small snacks help keep your energy levels steady. Good options include plain pretzels, bananas, fruit juice, fig newtons, rice cakes, and energy bars that you've tested during training. This is not the time to introduce new foods or products.
Prioritizing Hydration and Electrolytes
Adequate hydration is a cornerstone of ultra marathon success. In the 48 hours before the race, you should be consistently sipping fluids, aiming for a pale yellow urine color as an indicator of proper hydration. While water is essential, incorporating electrolytes is crucial to ensure you retain fluids properly and replace minerals lost through sweat. Many sports drinks or electrolyte tablets contain sodium, which helps your body hold onto water and boosts your thirst sensation naturally. Avoid excessive fluid intake that could lead to hyponatremia, but stay ahead of dehydration by sipping frequently. It's also wise to limit or avoid caffeine and alcohol during this period, as both can have dehydrating effects.
What to Avoid 48 Hours Before an Ultra
Your gut will be under significant stress during an ultra, so the 48 hours beforehand should be about giving it a rest. Foods high in fiber, fat, and spicy seasonings are your main enemies.
| Food Type to Limit/Avoid | Reason | Better Alternative |
|---|---|---|
| High-Fiber Foods (Raw vegetables, legumes, whole grains) | Can cause bloating and gastrointestinal distress. | White pasta, white rice, peeled potatoes. |
| High-Fat Foods (Fried foods, creamy sauces) | Take longer to digest and can lead to sluggishness. | Lean protein sources with light, tomato-based sauces. |
| Spicy Foods | Can irritate the digestive system and cause stomach upset. | Bland, familiar flavors you know your stomach tolerates. |
| Alcohol | A dehydrating agent that hinders muscle recovery and disrupts sleep. | Water, juice, or electrolyte drinks. |
| Dairy Products (in excess) | Can be difficult for some to digest, causing stomach issues. | Plant-based milks or limited intake of plain yogurt. |
| New or Untested Foods | You don't know how your body will react under race conditions. | Stick to familiar foods and nutrition products tested in training. |
A Note on the 'Two Nights Before' Meal
Many veteran runners follow the tradition of making their biggest, most carb-heavy meal two nights before the race, not the night before. This gives your body ample time to digest and store the glycogen without leaving you feeling bloated or heavy on race day morning. So, for a Saturday race, your high-carb dinner should be on Thursday night. Friday night's meal should be smaller and even simpler, further reducing the load on your digestive system. It's a small but effective strategy for optimal preparation.
Conclusion
Fueling properly in the 48 hours before an ultra marathon is a strategic process of maximizing carbohydrate stores while minimizing digestive stress. By focusing on low-fiber, easily digestible carb-rich foods, staying consistently hydrated, and avoiding common pitfalls like high-fat meals and new foods, you give your body the best possible foundation for a successful and comfortable race. Your pre-race diet is an extension of your training, and getting it right can make all the difference in your performance and enjoyment on race day. For more insights into race-day strategies, consult expert resources like Carmichael Training Systems' insights on pre-race fueling. Carmichael Training Systems
