Whole food fueling during an ultramarathon means: real ingredients as fuel, no synthetic gels, no artificial flavorings. It’s not a lifestyle choice. It’s race management. If you want the full picture on fueling for long endurance efforts, first read the complete guide on energy bars and endurance sports. Here, I address one specific question: why are more and more ultrarunners moving away from gels?

What is whole food fueling and why do ultrarunners choose it?

Whole food fueling is an approach where you choose nutrition based on recognizable, minimally processed ingredients during exertion instead of synthetic gels or isolated sugars. In the ultra world—races from 50km to 100 miles and beyond—that approach is growing rapidly. Not because it's a trend, but because practice demands it.

A fruit performance bar is a compact fuel source during exertion, built for race conditions. I designed my 25g bar specifically for that moment: enough carbs to be relevant, small enough to eat while you run. With each bar, you make a direct contribution to your carbohydrate intake without stopping, without forcing yourself to chew, without shoving a brick down your throat.

The switch is not a matter of taste. It is a performance decision driven by one concrete problem: stomach issues during prolonged exertion. Nausea, cramps, and vomiting are among the most reported reasons why runners don't finish their race or see their pace drop significantly.

Why do gels cause so many stomach issues during an ultramarathon?

A standard energy gel typically contains 20 to 25g of carbohydrates in a concentrated form. The sugar concentration of many gels is high. That means your stomach has to draw water from surrounding tissue to process the gel. At kilometer 5, that's manageable. At kilometer 60 of a 100km race, with a stomach that is already under pressure, it's a real risk for cramps and nausea. If you want to see the trade-off between both products clearly, read energy bar vs. energy gel: when to use what.

Then there is the composition. Many gels contain artificial colors, flavors, and preservatives. After four, six, or eight hours of exertion, the sensitivity to these substances increases for many athletes. The stomach becomes more selective. What worked in training no longer works on race day. I work exclusively with fruit and without artificials. That is not a marketing choice; that is functionality. More and more cyclists are making the same switch for the same reason: why cyclists are swapping gels for a clean label fruit energy bar.

Whole food fueling uses real fruit components as fuel. Real fruit naturally contains fiber, water, and a different sugar structure than isolated synthetic carbohydrates. Digestion proceeds differently. A 2:1 glucose/fructose mix utilizes two separate transport channels in the gut, a mechanism documented by Jeukendrup and Moseley in a 2010 controlled study. For more context, also read gastric emptying and how it works.

How does the 2:1 glucose/fructose ratio work?

Your gut uses two separate transport channels to absorb sugars. Glucose goes through one channel, fructose through the other. Two separate routes mean your absorption capacity is higher than with a product that taxes only one channel. With a 2:1 ratio—two parts glucose to one part fructose—you utilize both routes simultaneously without overloading either. This is not theory. It is the basis behind the entire shift from single to multiple carbohydrate products in sports nutrition.

Currell and Jeukendrup showed in 2008 that a 2:1 glucose/fructose mix improved time-trial performance versus glucose alone, because your body burns more external carbs and preserves your internal glycogen reserve. In 2022, Rowe and colleagues confirmed the same trend in runners based on exogenous carb oxidation and gastrointestinal tolerance. That mechanics is precisely why this is relevant for ultrarunners.

Based on 80g of carbohydrates per 100g, my 25g fruit performance bar delivers about 20g of carbs per bar, distributed across those two routes. Concrete, measurable, and built on fruit instead of powder.

How many carbohydrates do you need, and how do you distribute them?

For endurance exertion longer than 2.5 hours, the recommendation for trained athletes who utilize both transport channels is between 60 and 90g of carbohydrates per hour. King and colleagues found in 2019 that 90g per hour in a 2:1 ratio was the optimal dose over three hours of cycling. More was not better: higher doses impaired performance. Moreover, for ultra-endurance, it's less about the peak per hour and more about consistency over the entire distance.

Important: you don't get those 60 to 90g from bars alone. The structure that works:

• Sports drink as the main source. A drink with 6 to 8% carbs, 500 to 800 ml per hour, provides 30 to 60g per hour while keeping you hydrated simultaneously.
• 1 to 2 fruit performance bars per hour. Each with 20g of carbs, in the same 2:1 ratio. This is your reliable, solid-form component that your stomach recognizes.
• Optionally 1 gel in the finale. For high intensity at the end, if you need a quick peak.

Together, you easily reach your 60 to 90g per hour without overloading one channel or one texture. That is a workable protocol for an ultramarathon, and it relies entirely on whole food fueling.

What makes a fruit performance bar suitable for trail and ultra?

Trail running makes different demands than a road race. The terrain is unpredictable, your heart rate varies more, and climbing and descending alternate. That affects the blood flow to your gut, and therefore how stably your fueling is processed. A fruit performance bar scores concretely on four points here:

• Size. 25g fits in every vest pocket. No wrapper hassle on technical terrain.
• Consistency. No liquid, no gel that spills or sticks to your gloves.
• Composition. Fruit-based without artificials and a built-in 2:1 glucose/fructose ratio for a stably working protocol.
• Carbohydrate density. 80g of carbs per 100g. Functionally compact, without fillers.

The combination of clean ingredients and a functional 2:1 carb structure makes the bar a direct competitor to the gel. Not as a snack, not as a treat, but as fuel during exertion. That is the category. That is the position. By the way, the same logic works just as well on a training ride: the ideal fuel for your bike ride.

How does a fruit performance bar compare to other race options?

The bar performs better in carbohydrate density than dried fruit, has the 2:1 ratio that commercial bars lack, and combines that with a clean ingredient list that synthetic gels cannot match. You see that difference between clean and artificial most sharply when you place a fruit energy bar next to classic candy. No over-claiming, just a product specification you can read on the label. My bars are made at a certified Belgian production facility (BRCGS Food Safety, ACS), 100% vegan, gluten-free, and lactose-free.

No gel. No brick. Fuel.

Fruit as a raw material for sports nutrition is not nostalgia. It is a functional choice. Fruit naturally contains glucose and fructose together with fiber, moisture, and a sugar structure that your body processes differently than isolated synthetic carbohydrates. That is what I build on: fruit x effect. The ingredients are not decorative. They are the fuel.

Whole food fueling in an ultramarathon is not the easy way. It requires planning, a protocol, and knowledge of your own stomach. But the runners who do it, do it for one reason: it works. Clean fuel. More control. A stronger second half. No gel. No brick. Fuel during exertion that still works at hour ten. Fuel your flight.

Choose your fuel