Having a nutrition strategy is key for any endurance sport, but it’s particularly important for ultra trail running. Not only are ultra trail runners going insane distances over brutal terrain, but they often have to carry all their own nutritional supplies—meaning there's no room for error.
In a recent Nduranz podcast episode, we sat down with Elite Trail Team athlete Kristian (Kris) Jones to break down the key nutrition challenges ultra runners face and how to overcome them. From maximizing carbohydrate intake to managing hydration and whether supplements work, here’s what you need to know to go the distance.
You can listen to the full episode below. Or keep reading for Kris’s insights.
Fast Carbohydrates Are Key
Just like with any endurance sport, fueling with fast carbohydrates is key to success. The body only has enough glycogen stored for approximately 90 minutes of activity. Ingesting carbohydrates keeps glycogen levels from depleting so you can go the distance.
Focus on "fast" carbohydrates because they are the ones that the body absorbs and converts into useable energy most rapidly.
New to endurance sports? Read our Guide to Fueling
Kris has an Nduranz Nrgy Gel 45 in his pocket for fuel.
Aim for At Least 90 Grams Per Hour
When Kris Jones first started running ultra trail races, he consumed approximately 65 grams of carbohydrates per hour. His performance was okay, but he was "completely broken" by the end of races.
Exercise physiologist Dr. Tim Podlogar says that most trail runners should aim for at least 90 grams of fast carbohydrates per hour.
Kris actually consumes more than this. At the OCC in Chamonix, he had approximately 110 grams/hour, and his performance and recovery are better.
Pro Fact: The body can only absorb a limited amount of glucose at once, but fructose uses a different uptake pathway. To increase carbohydrate absorption, elite athletes fuel with a combination of glucose and fructose.
Drinks and Gels vs Solids on Ultras
As a general rule, ultra trail racers should stick to liquid and gel fuels. These break down rapidly for quick energy without digestion issues. By contrast, solid fuels take longer to break down and can bounce around in the stomach, causing discomfort.
However, Kris points out that, after 5+ hours of racing, you sometimes just want something solid. There’s a psychological aspect to fueling and chewing can help boost morale.
But, if you are going to use solids, make sure they have these characteristics:
- No/Low Fiber: Fiber slows down digestion and can cause GI problems during races.
- Soft Texture: This allows you to chew them without throwing off breathing.
- Glucose-Fructose Base: These simple sugars are best absorbed by the body for rapid energy.
The Nrgy Juice Bar 22.5 is a solid fuel which is still suitable for endurance activity.
Gut Training Is Key
During exercise, the body diverts blood from the digestive system and to the muscles. While this is essential for the muscles to perform, the reduced blood flow slows down digestion and can cause GI issues.
Gut training is a way to avoid these problems. It involves strategies like gradually increasing carbohydrate intake so you can consume large amounts of fuel without issues.
Read about Gut Training Strategies.
Avoiding Flavor Fatigue
Ever get 10 hours into a 15 hour race and suddenly are grossed out by the idea of consuming another gel? This is known as "flavor fatigue." Because it affects your ability to consume enough fuel, it can hinder performance.
There are a few ways of avoiding flavor fatigue, such as switching up gel flavors or alternating between drinks and gels. Kris says that using fuels with sodium also helps:
"If you just have all sweetness, it wears on the palate. But having that slight saltiness helps it go down better. Saltiness just makes you want to eat and drink, and when you're pushing these high amounts of fueling, it's really helpful."
Also read: How to Avoid Flavor Fatigue when Fueling
Bring Your Own Nutrition
One of the unique challenges of ultra trail races is that many don’t allow external crewing. You either have to bring all your own nutrition or pick up fuel and water from aid stations.
While it may be convenient, Kris’s advice is: don’t eat from the aid stations.
"The nutrition there is probably something you didn’t practice with, so you don’t know how your body will react. Further, you don’t know how long that orange slice has been sitting in the sun. It’s not worth the risk. Just bring your own fuel instead, even if it means starting with a very heavy pack."
Practice Fueling Plan in Training
Race day isn’t the time to experiment with fueling—you need a fueling plan that's been tested. That means training with the same fuels, in the same amounts, and under the same conditions you’ll face on race day. This way you know how your body will react so you don’t have unexpected surprises that destroy your performance.
Creating a Water Plan
According to Elite Trail Team Sports Dietitian Rebecca Dent, most ultra runners drink around 500ml of water per hour—but hydration isn't one-size-fits-all. Factors like climate, altitude, terrain, and individual sweat rate can all impact how much you need.
On top of that, access to water varies between races. Some courses have frequent aid stations and natural water sources, while others require you to carry everything you need. If you want to drink a lot of water, you will have to carry a lot of water—which adds weight and affects performance.
To find the right balance between having adequate water without weighing down your pack, Kris emphasizes the importance of breaking each race into sections and planning accordingly:
"You really have to problem-solve for each race individually. At OCC in Chamonix, we had three aid stations, but also water spouts along the course where you could refill. You need to really plan it out section by section—how long it takes to get from one water source to the next and how much you need to carry to get there."
Be Wary of Supplements
A ultra trail has gained popularity, we’ve seen a lot more athletes recommending supplements. But, as Dr. Podlogar warns, many of these athletes are sponsored by the manufacturers, which means they are incentivized to promote the product.
In his expert opinion, most supplements are not going to help ultra trail performance. He says to focus on dialing in training, fueling and hydration instead.
Which supplements are worth considering? According to Dr. Podlogar, one that definitely works is caffeine, though dosing properly is important for endurance events. He also says that electrolytes are important, especially for races lasting more than four hours.
What about Sodium Bicarbonate for Ultras?
Dr. Podlogar says that sodium bicarbonate may be helpful. Typically, sodium bicarb is used for short durations of high-intensity activity—such as a final sprint during a cycling race. This could be useful during certain sections of an ultra trail race, though Dr. Podlogar isn’t convinced it would really help on races this long.
However, sodium bicarbonate could help in another way: pre-race hydration.
Because it contains sodium, taking sodium bicarbonate before a race may allow the body to store more water—something that is important when you have to carry all your own supplies.
Want to hear more about ultra trail? Listen to the full podcast episode.