Nutrition in ultra-cycling: how to prepare your diet to avoid bonking during a race

It's 3:14 AM, somewhere on a deserted country road. I've been cycling for 19 hours. My legs are still turning, but my brain gave up an hour ago. I'm weaving slightly. Not because of muscle fatigue—because of hunger. I tried to "save time" by skipping my planned refueling stop at hour 16. Big mistake: in ultra-distance, a calorie you don't eat at the right time, you never truly catch up on. I pull over to the side of the road, eat a cold ham sandwich that's been in my pannier for three hours, and twenty minutes later, I'm cycling again as if nothing happened. That night taught me one thing that all ultra-cyclists eventually understand: in ultra-distance, you don't win a race with your legs. You win it with your plate.

Why nutrition makes (or breaks) an ultra-cycling race

In an event lasting several hours or days, the human body simply cannot ingest as many calories as it expends. An ultra-cyclist can burn between 8,000 and 10,000 kcal per day, equivalent to two to three marathons back-to-back. The real issue is therefore not "how to avoid all caloric deficit"—that's impossible—but how to prevent the blood sugar crash that causes hunger, a sudden drop in performance, and, like that night on my country road, the loss of lucidity that can turn a race into an accident.

Nutrition in ultra-cycling plays out on three levels simultaneously: energy intake (enough calories and carbohydrates), digestive comfort (not getting sick from eating), and the pleasure of eating (never losing the desire, at the risk of starving without realizing it).

How many calories and carbohydrates per hour in ultra-distance?

For any ride over 3 hours, aim for 60 to 90 g of carbohydrates per hour, mixing fast-acting gels with more calorie-dense real food. This range is the most important figure to remember from this entire article—almost everything else follows from it.

Less than 3 hours of effort: water alone may suffice, but 45 g of carbohydrates/hour already helps preserve energy.
3 to 8 hours of effort: 60 to 90 g of carbohydrates/hour, via a mix of gels + bars + real food.
More than 8 hours of effort: real food becomes essential, as taste fatigue makes gels difficult to swallow.
More than 24 hours of effort (audax, multi-day ultra): prioritize calorie-dense foods (4 g of calories or more per gram), otherwise it becomes physically impossible to carry enough energy in your panniers.

For hydration, the basic rule is to aim for 500 to 600 ml of liquid per hour, adjusted according to the weather, with one bottle of plain water and one light isotonic bottle alternately.

Eating before the race: filling reserves without sabotaging yourself

The 24 to 48 hours before the start are not for "carbo-loading" at the last minute—they are for quietly maximizing muscle and liver glycogen stores. Focus on complex carbohydrates with a low glycemic index (quinoa, basmati rice, sweet potato), supplemented with quality proteins and healthy fats, while avoiding foods too high in fiber or heavy fats that slow down digestion.

To do in the days leading up:

Eat your last real meal 3 to 4 hours before the start
Supplement with an easily digestible snack (banana, compote) 30 minutes before setting off
Reduce raw fibers and legumes the day before to limit the risk of intestinal problems
Never test a new food on race day—only products already validated in training

It was this last rule that saved me that famous night: the ham sandwich eaten in the cold was not an improvisation. I had tested it on three long rides before the race, precisely because I knew my stomach would tolerate it even when exhausted.

Eating during effort: the "before you get hungry" rule

The most common mistake in ultra-distance is not choosing the wrong food—it's waiting until you're hungry to eat. By the time hunger appears, the body has already been in an energy deficit for a while, and it becomes very difficult to catch up without going through a slump phase.

The strategy that works:

Eat every 20 to 30 minutes, in small quantities, at a fixed rhythm rather than based on hunger sensation
Alternate sweet and savory to delay taste fatigue (sandwiches, tabbouleh, makis, fries—many ultra-cyclists have their "guilty pleasures" and it works very well)
After 6 to 8 hours of effort, expect a progressive aversion to sweet foods and switch to savory or neutral options
Always keep an emergency reserve in your panniers (bars, dried fruit) for areas without possible refueling

Eating at night: the trap no one anticipates

This is the least known point, and yet the one that almost made me end up in a ditch that night. After a certain hour, what you eat directly influences your level of alertness. At night, it's better to favor protein-rich foods (nuts, sandwiches, protein shakes) and limit foods very rich in carbohydrates (gels, sugary energy drinks), because carbohydrates promote the production of serotonin and melatonin—the sleep hormones. Eating too much sugar in the middle of the night is literally giving your brain the signal to go to sleep, even though it still has to steer a bike on a dark road.

Night reflexes to know:

Reduce very sugary energy products after dark
Prioritize sandwiches, cheese, nuts, protein shakes
In case of severe fatigue, a strong coffee or a fast-acting sugar can provide a temporary boost, but the effect remains temporary
If drowsiness persists despite everything, a micro-nap of 10 to 20 minutes in a safe place remains more effective—and safer—than pushing yourself

Quick tips to remember

Aim for 60 to 90 g of carbohydrates per hour beyond 3 hours of effort
Drink 500 to 600 ml of liquid per hour, adjusted to the weather
Eat every 20 to 30 minutes, without waiting for hunger
Switch to savory/protein after 6 to 8 hours and especially at night
Never test a new food on race day
Always keep an emergency reserve in your panniers

FAQ — Ultra-cycling Nutrition

How many calories should you eat per hour in ultra-cycling?

Depending on intensity and rider weight, needs can go up to 800 to 1,000 calories per hour for the most sustained efforts, but the most reliable practical benchmark is to aim for 60 to 90 g of carbohydrates per hour beyond 3 hours of effort.

What to eat at night during an ultra-cycling race?

Prioritize protein-rich foods (sandwich, nuts, shake) rather than very sugary products, as carbohydrates promote drowsiness by stimulating melatonin production. Coffee or a fast-acting sugar can help temporarily in case of fatigue.

How to avoid food aversion on a multi-day ultra?

By varying textures (crunchy, soft, liquid) and flavors (sweet/savory), and deliberately including pleasure foods. Losing the desire to eat is a real danger in ultra: it directly leads to energy depletion.

Should you eat before you're hungry in ultra-distance?

Yes, systematically. Waiting for the sensation of hunger means that the energy deficit is already established. The most reliable rule is to eat in small quantities every 20 to 30 minutes, at a fixed rhythm.

Which foods to prioritize beyond 8 hours of effort?

Real food (sandwiches, tabbouleh, dried fruit, cheese) becomes essential, as taste fatigue makes energy gels difficult to swallow past this point.

How much to drink per hour in ultra-cycling?

Approximately 500 to 600 ml of liquid per hour, alternating plain water and light isotonic drink, to be adjusted upwards in hot weather with additional electrolyte intake.

Can you test your nutrition on race day?

No, never. Every food, gel, or drink consumed during the race must have been validated beforehand during long training rides, to avoid any risk of unforeseen digestive problems.

Conclusion: your plate, your real starting line

That night on the country road, it wasn't my bike that almost gave out on me—it was my refueling plan. Since then, every long ride is also training for my stomach: I test, I note what works and what doesn't, I build my plan hour by hour like building an itinerary. In ultra-cycling, nutrition is not a logistical detail you sort out the day before—it's a skill that is trained exactly like pedaling. Next time you prepare for a long ride, start with your refueling plan even before thinking about your route: it will decide, much more than your legs, how far you will go.