Running ultramarathons places massive demands on the body, requiring a strategic and well-practiced fueling approach. This article provides a comprehensive guide to nutrition for ultra runners, covering everything from daily diet to race-day fueling and recovery.
The Importance of Nutrition for Ultra Runners
The key to success for an ultra runner lies in the ability to maintain a constant and high rate of energy output over a prolonged period. Both training and nutrition play a vital role in achieving this. Ultramarathon fueling isn’t just about eating-it’s about strategic fueling that keeps you steady for hours without gut issues or glycogen depletion.
The nutrition strategy adopted by ultra runners can significantly impact their finish times and overall enjoyment. Data shows that the energy expenditure during ultra events that extend beyond 24-hours is anywhere between 13,000 and 17,750 kcal. Failing to meet basic energy requirements can impair performance, recovery, immune function and increase the risk of injury.
Daily Diet for Ultra Runners
On a day-to-day basis, it's crucial to stick to a well-balanced diet rich in protein, vegetables, and carbohydrates, the cornerstone of endurance performance. Diana Green, an experienced nutritionist and chef who is also a keen runner and mountain biker, emphasizes the importance of planning meals in advance on both training and rest days.
Macronutrient Balance
- Carbohydrates: As ultra-runners, we’ve earned those cookies. During these days, it's advisable to arrange meals to be more carb-based. The average runner can store about 2,500 calories of carbohydrate. During a typical training week, one might consume 11 portions of carbohydrates and fruit throughout the day. Pre race carb loading while reducing training for 3 days before an event will increase muscle carbohydrate stores.
- Protein: Choose protein foods with a high biological value (containing a complete balance of amino acids which can be readily used by the body) lean meats, fish, eggs, low fat dairy and soya.
- Fats: Once protein and carbohydrate requirements are calculated, the remainder of calories come from fat aiming for approx 25% of total calories. Fat is a critical component of the ultra-runner’s diet-both as a dense energy source of fuel and a tool to drive metabolic adaptations. During base training, strategically increasing dietary fat, while also reducing carbohydrate intake, can dramatically increase fat oxidation up to 2 grams per minute, spare glycogen, and enhance endurance efficiency.
Hydration
Be sure to stay well-hydrated during the days leading up to your race. Individual requirements will vary. It is important to supply enough fuel to support your energy requirements and recovery.
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General Dietary Rules
Here are some of the basic rules that you need to apply every day in order to maintain optimal health and fitness.
- Plan your meals in advance on both training and rest days.
- Body weight can affect your performance. Decide on a weight target to reduce your weight, aim for a reduction of approx 500 calories a day below your energy requirements. Likewise if you want to increase your weight, add an extra 500 calories per day.
- For any diet to be sustainable it must be enjoyable.
- Create simple meals based around your dietary targets.
- Don’t over focus on a few ‘superfoods’.
Pre-Race Nutrition
Each of us must carefully plan our nutrition and hydration strategy well in advance of the actual race. I suggest you try absolutely everything out there to see what works best for you. Do not try anything new on race day.
Carb-Loading
And let’s not forget the fun part: carb-loading before a big race. During these days, I generally arrange my meals to be more carb-based. Pre race carb loading while reducing training for 3 days before an event will increase muscle carbohydrate stores.
Pre-Race Meal
Eating a few hours ahead will leave you feeling strong at the start line, but you may still need a little boost right before the gun goes off. My pre-race dinner has been the same for the past decade.
Race-Day Fueling
On the day of the race, the number one priority is maintaining adequate energy availability. Finishers of 100-mile races consistently consume ~70 g/h, while non-finishers average less than 45 g/h.
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Carbohydrate Intake
The most important thing is to consume enough carbohydrates during your race to avoid hitting the wall. In my case, I weigh 51 kilos, so I need to consume 51 grams of carbohydrates per hour during my races. Carbohydrates are the foundation of race-day fueling. They fuel and maintain the required race pace and support mood and cognitive function. Research typically suggests 60-90 g/hour, although more recent research has indicated that 120 g/hour at a specific 1:0.8 ratio of glucose to fructose might be more beneficial, perhaps reserved for particularly intense or mountainous sections of the race. Dual fuel carbohydrates (glucose + fructose) improve absorption through separate intestinal transporters, allowing higher hourly intake without GI distress.
Fueling Options
As ultra-runners, it is also essential to try solid food while training. When checking, be sure you pay attention to the serving size the nutrition facts represent. It’s easy to misread a label, as sometimes it refers to a larger quantity of the product in the actual packet. Gels can range anywhere from 16 - 25 grams of carbs, depending on which ones you choose, and sports drinks also have a wide range of carb intake.
Hydration Strategy
To determine your optimal hydration for ultramarathons, it’s essential to undergo a sweat test. When taking a sweat test, try to simulate your race conditions as closely as possible-consider the climate, terrain, and intensity of your effort. After calculating your liquid loss, aim to replace at least 80% of that figure during your race. Hydration must be personalized.
Electrolyte Balance
Maintaining fluid and electrolyte balance during an ultra is another obvious issue. Research shows average fluid intake during a 24-hour race is ~378 mL/h, yet some athletes consumed up to 673 mL/h, often through plain water with no sodium. Hyperhydration via plain water can lead to exercise-associated hyponatremia. The sodium concentration of the fluids consumed is equally important and should ideally exceed 500 mg/L, especially in warm climates or long races.
Backup Plan
That said, I always bring a backup option just in case. It’s always better to be over-prepared than underprepared. Always overshoot and bring more than what you think you may need.
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Post-Race Recovery Nutrition
To ensure a successful recovery, you must continue to fuel your body after an ultramarathon. Your muscles are depleted, your glycogen stores are low, and your body has undergone hours of physical and mental stress.
Initial Recovery
Everyone reacts differently upon finishing an ultramarathon. Some runners cross the line ravenous, ready to devour anything in sight, while others feel nauseous or too exhausted to even think about food. Aim to take in a recovery drink within 30 minutes of finishing. This window is crucial because your muscles are primed to absorb nutrients and begin repairing. Look for a drink with a 3:1 or 4:1 ratio of carbohydrates to protein. Aim for 300-400 calories of 4:1 grams of carb to protein.
Long-Term Recovery
Finally, remember recovery nutrition isn’t just about the first meal-it’s a 24-48 hour process. Continue to eat nutrient-dense meals and snacks, hydrate consistently, and avoid under-fueling in the days following your race. This sets you up not only for a faster recovery but also for long-term health and future training.
The Bullseye Nutrition Strategy
Jason Koop, Head Coach of CTS Ultrarunning, devised a specific nutrition strategy to deal with the unique nutritional challenges ultramarathon runners face because of the length of the event, distance between aid stations, changes in the environmental conditions, fatigue leading to poor decision making, and food or flavor fatigue.
Developing Your Bull’s-Eye Foods
Variety is important in your short list of bull’s-eye foods. The end goal is to find a combination of three to five foods that, together, meet all the following criteria:
- At least one engineered food (gel, chewable, or calorie-rich drink)
- At least one real food-something you make or assemble or that is not made specifically for running (rice ball, peanut butter and jelly sandwich, or pretzels)
- Something sweet
- Something salty
- Something savory
Experimentation and Categorization
During training, particularly during the longer runs, I have athletes experiment with different-and sometimes counterintuitive-foods to help them reach their target calorie ranges. Foods that work are easy to open and eat on the run. They taste good, don’t get stuck in your teeth, and make you run as well as or better than you were running before eating them. Foods that don’t work are difficult to open, messy, crumbly, and hard to hold in one hand. They get stuck in your mouth, are too dry, or are tough to swallow without choking. Most of all, they sit in your gut like a calorie bomb, make you feel bloated or full, and slow you down.
All the food options you try can be categorized by where they fall on a target. Your bull’s-eye foods are your tried-and-true favorites. If these core foods begin to fail, because you’re tired of eating them, craving more sweetness or saltiness, or craving a different texture, then you can choose foods from the next ring of the target. These are foods you may not eat all the time, but you have tried them in training and know they work for you.
Anything beyond this ring is off target altogether. These are the foods you know don’t work for you and foods similar to foods that don’t work for you. It is important to list these foods out, as well, so you and your crew are reminded of the things you have tried that have not worked in training.
Backup Foods
After these core foods have been fully vetted, experiment with backup (second-ring) foods. These backup foodstuffs are what you can confidently fall back on when you lose your taste or craving for your bull’s-eye foods. The typical fallback plan revolves around the aid station fare of cookies, soup, fruit, and sandwiches.
Gut Training
The gut is trainable, just like a muscle. So gut training during the preparation period is absolutely critical. As previously mentioned at the beginning of the training block start with 30 g/h and progress toward the race recommendations of 60-120 g/h using dual fuels to familiarise the gut and ensure tolerance, not just absorption.
Mental Aspects of Ultra Running Nutrition
In ultra-endurance racing, it is rarely the legs that fatigue first-it’s the mind. Integrating psychological skills training into every ultra-runner’s preparation, including visualization, coping strategies, positive self-talk, and task-focused thinking is very important. Cognitive performance during ultra-races is highly sensitive to blood glucose availability. Studies have shown that carbohydrate restriction or underfueling impairs reaction time, decision-making, and motivation.
Special Considerations for Female Ultra Runners
Female ultra-endurance athletes are not simply smaller versions of their male counterparts. They have unique physiological, hormonal, and nutritional needs that must be considered and addressed. Women oxidize significantly more fat at submaximal intensities than men-24-56% higher fat oxidation per kg of fat-free mass during endurance activity.