Nutrition for Endurance - Fuelling for Performance
Hello, hope you have been keeping well.
Last week I just completed the UTMB Istria 100 42km in Croatia and fair to say it was more slightly harder than anticipated. The hills were much steeper than the elevation map made out and the terrain was mainly rubble making it difficult to run under feet and really worked my ankle stability. Nevertheless, it was a fantastic run and recommend any running enthusiast to check it out, especially if you’re a beginner in ultrarunning. It got me thinking though about nutrition and fuelling for races and how its changed over time for me. With Boston and London marathon coming up very soon, a lot of runners will be focusing on dialling in the nutrition leading up to the race, during the race and post-race. In this post I discuss about why carb-loading is essential for endurance races, what type of foods should you be eating, how to adjust my food intake for your weight and goal time and much more.
Marathon and Ultramarathon Nutrition: How to Fuel for Success
When it comes to long-distance running, fuelling your body properly is just as important as you’re training. Whether you're preparing for a marathon or an ultramarathon, your nutrition plays a crucial role in ensuring you have the endurance, energy, and recovery needed to complete the race successfully. In this post, we'll break down marathon and ultramarathon nutrition, with a special focus on how to carb-load in the lead-up to race day.
The Importance of Marathon and Ultramarathon Nutrition
Any long-distance endurance race puts extreme demands on the body. You will be running for hours, your muscles will be burning through its glycogen stores and then rely on your fat for fuel. To prevent bonking or some cases passing out, the body needs to tap into its energy reserves to keep you going. Having a planned nutrition strategy will help you avoid hitting "the wall" and will aid you in completing the race or even hitting your PB. That’s why carb-loading in the days prior to the event, and during is going to be the tipping point in achieving what you set out to do from the start. A lot of people today will overcomplicate the type foods you need to consume but if you can understand the basics, like the different types of macronutrients your body needs in order for it to thrive off then fuelling for your performance should be easier. I’ve broken it down below simply for anyone to understand:
Carbohydrates: Your primary energy source for long runs.
Protein: Important for muscle repair and recovery.
Fats: Provide long-term energy for ultramarathons.
Electrolytes: Help maintain fluid balance and prevent cramps.
Hydration: Vital for maintaining performance and avoiding dehydration.
Carb-Loading: The Foundation for Long-Distance Success
Carb-loading is a common strategy when it comes to preparing for a marathon or ultramarathon. The idea is simple, increase your carbohydrate intake in the days leading up to the race to maximize your glycogen stores. Glycogen is the primary fuel source for endurance runs and having a full glycogen stores will help you maintain your goal pace and prevent you from crashing out of your race. To break it down scientifically, your muscles store carbohydrates in the form of glycogen, which is used as fuel. However, your body’s capacity to store glycogen is limited. By carb-loading, you increase your glycogen stores and ensure you have plenty of fuel during the race. Normally, carb-loading involves a "depletion phase" followed by a "loading phase," but today the common strategies focus more on simply increasing carbs in the days leading up to the race without a depletion phase. Either way, the goal is to ensure that your glycogen stores are maximized by race day. Me personally, I like to reduce my carb intake 4-7 days out from the race and then increase my carb intake 2-3 days out from the race. Ensuring my glycogen stores are at full capacity when it comes to race day.
Below I’ve gone over how you can implement carb-loading strategy for your next race and the key things to consider with your carb-load:
Timing: Start your carb-loading 2–3 days (48-72 hours) before the race. Start increasing your carbohydrate intake to about 70% of your total daily calories. This can be as easy as adding and additional slice of toast to your breakfast, increasing the amount of rice/pasta you have at dinner or snacking on a high carbohydrate snack like a rice crispy bar.
Choose the Right Carbs: Focus on easily digestible, low-fibre carbohydrates such as white rice, pasta, bread, and potatoes. Try and avoid foods that are too high in fibre, as they can cause stomach issues, and you don’t normally eat. Its’s important you eat the foods that you know you are comfortable with. Eating this volume of carbohydrates can be difficult so consider drinking them instead such as sport isotonic drink or apple or orange juice but be careful about consuming too many liquid carbohydrates as this could cause stomach issues.
Gradual Increase: Don’t go from a normal diet to a carb overload all at once. Gradually increase your carbs to allow your body to adjust. For example, if you usually eat 300 grams of carbs a day, you could aim for 300–400 g the three days before your race and then increase it to 500-600g of carbohydrates to days before.
Keep Protein and Fat Moderate: While carbs should dominate, don’t neglect protein and fat. Aim for a balanced diet, but keep your protein intake moderate, roughly around 15-20% of your total calories and limit fat to 10-15%. Having too much fat can slow digestion and may leave you feeling sluggish.
Example Carb-Loading Meal Ideas
Breakfast: Oatmeal with banana and a drizzle of honey, three eggs with 3 slices of toast, Greek yoghurt with granola and berries and honey.
Lunch: Ham or chicken sandwich with a side of fruit or chicken and rice/potatoes and some vegetables.
Dinner: Pasta with tomato sauce and a side of garlic bread or a low-fat cheese pizza with a rice crispy bar for dessert.
Don’t forget to stay hydrated, as water helps your body store glycogen more efficiently. Make sure you are including an electrolyte tablet/sachet in your morning water glass and aim to consume 2L of water per day.
How to Match Your Carbohydrate Intake with Your Body Weight and Race Goal Time
Ok now the slightly tricky part, matching your carbohydrate intake with your body weight, race goal time and the intensity of your race. The amount of carbs you should consume depends largely on these factors.
Carb Intake Based on Body Weight
A common recommendation for carb-loading is to consume 7-10 grams of carbohydrates per kilogram of body weight per day in the 2-3 days before the race. This range can vary depending on how long your race is and your overall training intensity. For example, if you weigh 80kg (180 lbs), you will need to consume 490-700 grams of carbohydrates per day during the carb-loading phase (7-10 grams per kg of body weight).
Carb Intake Based on Race Goal Time
If you have a race goal time in mind, then this will also influence how much carbohydrate you need to consume. If you're aiming for a fast marathon time, a sub-3-hour time let say, your body will require more glycogen to fuel that higher-intensity effort. On the other hand, if you're running at a slower pace or participating in an ultramarathon, you may rely more on a combination of carbs, fats, and a little protein, but still need to maintain a solid carb intake to avoid depleting your glycogen stores too quickly.
For a marathon: Runners will typically aim to consume 30-70g of carbs per hour of racing. However, if you plan to run a marathon in under 3 hours, you might need to increase that amount closer to the upper end of the range of 60-100g per hour.
For an ultramarathon: You may need to adjust for longer race times. Carb intake during the race can range from 60-90g per hour, and you might need to include some protein and fats in your fuelling strategy to maintain your energy levels over several hours of running.
Adjusting Carb Intake Based on Performance Goals
If your goal is to achieve a specific time, then you should aim for the higher end of the carb intake loading scale to ensure you have enough glycogen for a faster-paced effort. If your goal is too simply finish, you might not need as much but it’s still essential to maintain consistent carb intake during the race to avoid running out of energy. Here’s an example of a breakdown for Carb-Loading and Intake:
Let’s say you weigh 80kg, and you’re aiming for a marathon time of 3:30 hours. Here’s an idea of a breakdown of your carb-loading and race-day fuelling plan could look like:
Carb-Loading (2-3 Days Before the Race):
Carbs per Day: 7-10 grams per kg of body weight = 560-800g of carbs per day
Focus on easy-to-digest complex carbs, such as pasta, rice, potatoes, and bread, along with moderate protein intake.
Race Day (During the Marathon):
Carbs per Hour: Aim for 30-70g of carbohydrates per hour.
You could do this by consuming energy gels 20-40g of carbs per gel or a sports drink with 15-20g of carbs per serving. Again, it’s important to try and test gels and sports drinks to see what works for you.
By customizing your carbohydrate intake based on your body weight and race goal, you can ensure you’re fuelling adequately for the demands of the race, whether you're aiming for a personal best or simply crossing the finish line.
Nutrition During the Race
Whether you're running a marathon or an ultramarathon, it’s important to stay fuelled throughout and keep your glycogen stores topped up. A common mistake, which I fell trap to was not consuming enough and end up crashing towards the end of the race. The key is to fuel earlier then you think! Don’t fuel when you feel tired or when you think you need a boost, below is an idea of how many carbs you need to consume during the race:
For Marathons: Depending on intensity, the research suggests the average person should aim to consume 30–60g of carbohydrates per hour during the race. For heavier runners or runners who are aiming to run a fast time, you are looking at 80-100g of carbohydrates per hour. This can be achieved using energy gels, chews, or sport drinks that are designed for endurance athletes. It's always so important to try and test your nutrition plan in your training and stick to gels/foods/drinks you are comfortable with and avoid trying something new on race day. It could massively backfire!
For Ultramarathons: As ultramarathons often last longer than marathons, you may need to consume a wider variety of nutrients. In addition to carbohydrates, you’ll want to include some protein and fats to maintain energy over the long haul. This might mean eating real food, such as peanut butter sandwiches, bananas, or trail mix, in addition to sports nutrition products.
Electrolytes: Both marathon and ultramarathon runners need to replace lost electrolytes. Consider using sports drinks or electrolyte tablets to prevent cramping and keep your fluid balance in check.
What People Get Wrong About Fuelling and Carb-Loading: Avoid These Mistakes
While fuelling and carb-loading may sound straightforward, many runners get it wrong, leading to fatigue, gastrointestinal distress, or even worse, hitting the infamous "wall" during the race. Here are some common mistakes and how to avoid them:
Overloading on Simple Carbs
Not all carbs are created equal. While simple carbs like sugary snacks or candy might give you a quick burst of energy, they don’t provide the sustained release of glucose that complex carbs like whole grains, pasta, or sweet potatoes do. Stick to complex carbs but don’t be worried about treating yourself to an odd cookie or a croissant just to help your cravings (and out of course help with the carb intake)!
The problem: Relying too much on simple sugars can cause blood sugar spikes and crashes, leaving you feeling sluggish or fatigued as the race progresses.
The solution: Focus on complex carbs for most of your carb-loading. Whole grains, pasta, quinoa, and starchy vegetables provide a steady release of glucose, ensuring your body has a consistent supply of energy throughout the race.
Underestimating Fluid Intake
You can carb-load all you want, but if you're not properly hydrated, your body won’t store glycogen as efficiently. Water is essential for glycogen retention. Without enough fluids, your body won’t be able to store the carbohydrates effectively, and you’ll likely feel sluggish on race day.
The problem: Many runners focus so much on food that they forget about hydration. Dehydration can also increase the risk of cramps and muscle fatigue during the race.
The solution: Along with your increased carbohydrate intake, make sure you’re also increasing your water intake in the days leading up to the race. Drink consistently, aiming for around 2-3 litres of water per day.
Skipping the Protein
While carbs are the star of carb-loading, protein also plays an important role in your race-day nutrition. Some runners overlook this macronutrient during carb-loading, but protein is necessary for muscle repair and recovery.
The problem: Not including protein in your diet before the race can leave you vulnerable to muscle fatigue, soreness, and longer recovery times after the event.
The solution: Aim for a balanced ratio of carbs to protein in the days leading up to the race. A moderate intake of protein, around 15-20% of your total calories, will support muscle recovery and reduce soreness after your long run.
Final Thoughts
Nutrition is an integral part of marathon and ultramarathon performance. Understanding how to properly carb-load, match your intake with your body’s needs, and avoid common mistakes can make the difference in your race results. Listen to your body, experiment during your long runs, and adjust your strategy as needed to find what works best for you. With the right fuelling strategy, you’ll be prepared to perform at your best on race day.
While marathons require significant fuelling, ultramarathons present unique challenges. Races that last six hours or longer will demand continuous fuelling, so consider this:
Eating Real Food: During an ultramarathon, there are plenty of stations where you will be offered a plethora of sweet and salty snacks like coke, cheese, meat, pretzels, Nutella, fruit, bread etc. but it’s important to stick to what you will sit with your stomach best. You may want to carry solid foods like energy bars, fruit, sandwiches, or nuts for sustained energy over the course of the race.
Frequent Hydration: Drink consistently, even if you’re not thirsty. Dehydration can sneak up on you during long races especially in warm weather.
Experiment in Training: Since ultramarathon races can last for hours, experiment with different nutrition strategies during your long runs to find what works best for your stomach.
Proper nutrition and carb-loading are essential for marathon and ultramarathon success. By strategically increasing your carbohydrate intake in the days leading up to the race, staying fuelled with the right balance of carbs, protein, and fats during the event, and prioritizing recovery afterward, you can give yourself the best chance of achieving your race goals. Remember, nutrition is highly individual, so it’s important to test your plan during training and adjust it to suit your personal needs.
Good luck, the hard work has been done. The hay is in the barn and the final touches to your race day plan are being tuned. You’ve got this, go out now and enjoy the race.
Weekly Podcast Episode Rec:
“If you think junk food is bad for you, let me tell you how bad under-fuelling is”. Cortney shares key insights on fuelling and nutrition, the differences between fuelling for both genders, a deep-dive into fuelling during your period, why how much you eat is more important than what you eat and much more.
Life/Travel/Running Hack
Freeze grapes to chill your drink without it getting watered down. With summer getting ever closer to summer this one is a must try. The next time you're making a drink that you don't want to be diluted by the water when it melts use frozen grapes instead of ice cubes. That way when it melts, your drink won't be watered down. Small game changer for your summer drink of choice.
Something I’m pondering ‘Food for Thought’
“There are no solutions, just trade offs.”
Thanks for reading and subscribing.
It’s better to miss home than it is too miss out on the world
