Anything beyond 26.2 miles enters ultramarathon territory - 50K, 50 miles, 100K, 100 miles, or beyond. At these distances, nutrition isn't just important, it's survival. The strategies that work for shorter races need significant modification.
If a marathon is about glycogen management, an ultra is about sustained calorie intake. You can't carry enough stored energy for 8+ hours of running. You'll be eating during the race, which changes how you prepare.
The Ultra Reality (The Science)
Your body stores roughly 2,000 calories of glycogen - enough for 90-120 minutes of running. You burn 600-1000 calories per hour during an ultra. An 8+ hour event requires 4,000-10,000+ calories - impossible to store. Ultra success depends on during-race nutrition: 200-400 calories per hour. Pre-race nutrition is about full glycogen tanks AND a trained gut that tolerates food while running.
The Week Before
7-4 Days Out
Reduce training, maintain normal eating. Focus on foods you know work well for you. Start prioritising sleep. Stay well hydrated throughout.
3-2 Days Out
Begin carb loading - similar to marathon preparation but slightly less aggressive. 7-10g carbs per kg bodyweight daily. Reduce fibre significantly. Choose white rice, white pasta, white bread. Avoid anything that might upset your stomach.
Day Before
Continue high carbs, very low fibre. Eat dinner early (5pm). Familiar foods only. Many ultra runners eat something bland like plain pasta with olive oil and salt. Drink plenty of water but stop early evening to avoid disrupted sleep.
Race Morning
Ultra starts vary - some begin at 6am, others at midnight. Adjust timing accordingly, but the principles remain:
- 3-4 hours before start: Substantial breakfast (500-700 calories). Porridge, toast, familiar carbs. Maybe some protein.
- 1-2 hours before: Small top-up if needed. Banana, small natural energy bar.
- 30 mins before: Final sips of water or sports drink. Use toilet.
Don't eat more than normal thinking you need extra fuel - you'll be eating during the race anyway. The goal is starting comfortably full, not stuffed.
The Key Difference: Train Your Gut
Unlike shorter races, ultra success depends on eating while running. Your gut needs training for this - it's not natural. In the months before your ultra, practice eating during long runs. Find foods that sit well while moving. Know exactly what you'll eat on race day before race day arrives.
Race-Day Nutrition Strategy
During-Race Fuelling
This is where ultra nutrition differs most from marathons. You need 200-300 calories per hour, every hour, for the duration of the race. Common approaches:
- Aid station food: Most ultras have substantial aid stations with real food - sandwiches, soup, fruit, potatoes, crisps
- Personal supplies: Natural gels, natural energy bars, and whatever works for you
- Real food: Many ultra runners find real food easier to stomach than gels after 4+ hours
- Savoury options: After hours of sweet gels, salty foods (crisps, broth) become appealing
Critical: Practice your exact race-day nutrition strategy during training. Stomach issues are the #1 reason for DNFs in ultras.
Hydration Approach
Ultra hydration is different from marathon hydration:
- Don't overdrink: Hyponatremia (low blood sodium) is a serious risk in long events
- Drink to thirst: Modern guidance for ultras is to drink when thirsty, not on a schedule
- Include electrolytes: Essential over long durations - sodium tablets, electrolyte drinks, salty food
- Pre-race: Be well hydrated but don't overload on water the day before
Common Pre-Ultra Meals
Ultra runners tend toward bland, reliable foods:
- Night before: Plain pasta with olive oil and salt, rice with chicken, simple carb-based meals
- Race morning: Porridge, toast with jam, bagels, overnight oats - nothing fancy
- Top-ups: Bananas, rice cakes, small amounts of familiar foods
The more extreme the distance, the more conservative the food choices. This isn't the time for culinary adventure.
Night Runs & Multi-Day Events
If your ultra starts at night or runs through the night:
- Eat a normal dinner as your "pre-race meal" (3-4 hours before start)
- Adjust your sleep schedule in the days before if possible
- Consider caffeine strategy - when will you use it to stay alert?
- Pack foods you can eat in the dark
For multi-day events, recovery nutrition between stages becomes critical - that's a whole separate topic.
Evidence-Based Pre-Ultra Summary
- ACSM carb loading: 10-12g/kg for 36-48h (can increase glycogen 25-100%)
- Reduce fibre significantly - low-residue diet reduces GI issues
- Studies show GI distress is #1 DNF cause - familiar foods only
- Breakfast 3-4 hours before (1-4g/kg carbs, ISSN recommendation)
- Gut training: adaptable - practice eating at race pace
- During-race target: 200-400 calories/hour (up to 90g carbs/h with gut training)
- Hyponatremia risk: Drink to thirst, include 500-1000mg sodium/hour
After your ultra, recovery becomes paramount. See our guide on what to eat after an ultramarathon.
← Back to Running & Races
