Gravel bike nutrition: how do you fuel for 80 km off-road?
TL;DR — On an 80 km gravel ride, you need 60 to 90 grams of carbs per hour. You don't get that from a single source. Sports drink is your foundation; 1 to 2 fruit performance bars per hour supplement it. The 2:1 glucose-fructose ratio uses two separate transport channels in your gut, allowing you to absorb more without stomach issues. Start within the first half-hour. Anyone who waits until they are hungry to eat is already too late.
Gravel cycling nutrition revolves around one principle: fueling on time, in the right ratio, without the hassle. No schedule you have to remember while steering over loose gravel. A plan you execute without thinking about it. The basic rules apply to every long ride, and I laid those out in the complete guide to energy bars and cycling. On gravel, a few extra things come into play.
Why gravel is more demanding than the road
On the road, you are tucked in a wheel. Your heart rate is predictable, your speed is high for the effort you put in, and you eat at set times in the peloton. On gravel, you are largely on your own. No slipstream. You climb, descend, absorb vibrations, and constantly adjust your steering on gravel, sand, and mud.
That asks for more than just your legs. Your upper body is involved, your grip requires strength, and your power output fluctuates by the second. On an 80 km ride with 600 to 900 meters of elevation gain, you are easily in the saddle for 2.5 to 4 hours. A 70 kg rider easily burns 2,000 kcal and more in that time.
Your own stores don't cover that. Glycogen, the sugar reserve in your muscles and liver, amounts to about 400 to 500 grams in a trained rider. Sounds like a lot. It isn't. Without an external supply, you'll deplete that reserve halfway through, and then you'll hit a wall at the worst possible moment: on a technical section where you need to keep your head in the game.
How many carbs do you need for 80 km of gravel?
The guideline in endurance sports is clear. Above 75 minutes, you need external carbs. For rides of 2 hours and longer, aim for 60 to 90 grams per hour, depending on intensity and how well-trained your gut is.
Going above 90 grams becomes counterproductive. King and colleagues had trained riders cycle for three hours with increasing doses. They performed best at 90 grams per hour. At 100 grams per hour, their performance in the subsequent time trial decreased because the excess could no longer be absorbed and the riders had to rely more on their own muscle stores. So, more is not better. More is simply more weight in your gut.
Ninety grams per hour is not a starting point, either. Start at 60 and build up during your training rides. Your gut gets used to higher intake, just as your legs get used to higher wattages.
Why the 2:1 ratio makes the difference
Glucose enters your blood via one specific transport channel in your gut wall, called SGLT1. That channel reaches its capacity at around 60 grams per hour. Anything that comes in above that stays in your gut, attracts moisture, and gives you exactly what you don't want: cramps, nausea, and a stop on the side of the road at kilometer 55.
Fructose uses a different channel, GLUT5. Using two channels at the same time means you can process up to 90 grams per hour without overloading your stomach. That is the entire logic behind the 2:1 ratio: two parts glucose, one part fructose.
The effect has been measured, not just theorized. Currell and Jeukendrup had trained cyclists ride for two hours and then perform a time trial. The group on glucose and fructose in a 2:1 ratio rode that time trial 8% faster than the group on glucose alone, and 19% faster than those on water. Jeukendrup and Moseley also showed that the same ratio accelerates your gastric emptying, so that fuel and fluids flow through more quickly to where you need them.
My fruit performance bars are built on that ratio. 80 grams of carbs per 100 grams, 20 grams per 25-gram bar, in a 2:1 ratio. Not a coincidence, but the reason the product exists.
Gel, classic bar, or fruit performance bar on unpaved surfaces
Gels are fast, but on gravel, they work against you. You are riding with gloves, the terrain is vibrating, and tearing open a package while navigating a gravel section is not the right moment. Moreover, many gels provide only glucose, which brings you to that 60-gram ceiling. I compared when a gel makes sense and when it doesn't in energy bar versus energy gel.
Classic bars are the other extreme. Compact and dry, but hard to chew when your breathing is already heavy. They stick to your teeth, and you need water to swallow them. On a long climb, such a bar becomes an obstacle instead of fuel.
A fruit performance bar sits in between. Soft enough to eat while riding, firm enough not to fall apart in your back pocket. About half fruit pulp, no artificials, vegan, gluten-free, and lactose-free. I wrote about why more and more riders are making the switch in this piece on trading gel for a clean label.
| Fuel | Carbs per piece | 2:1 ratio | Usable on gravel | No artificials |
|---|---|---|---|---|
| Standard gel | 22 to 25 g | Sometimes | Difficult with gloves | Often not |
| Classic energy bar | 30 to 40 g | Rarely | Dry, requires water | Variable |
| Fruit performance bar 25 g | 20 g | Yes | Soft, ready to eat | Always |
My fuel plan for 80 km of gravel, hour by hour
One thing first: you will never get 60 to 90 grams per hour from bars alone. That would be four or five per hour, and no one can chew through that on a technical course. Your bottle is your base, the bar supplements it. This is what it looks like.
2 to 3 hours before the start
A carbohydrate-rich meal. Oatmeal, rice, or whole-grain bread with fruit. You either start with full reserves or you start with a deficit. There is no middle ground.
The first half-hour
Start drinking as soon as you roll out, and take your first bar within 30 minutes. Do not wait until you feel hungry. Hunger during exertion means you are already lagging, and you won't make up that deficit on gravel.
Every hour after that
Plan for 500 to 800 ml of sports drink with 6 to 8% carbs per hour. That provides 30 to 60 grams. Add 1 to 2 fruit performance bars to that, good for 20 to 40 grams. Together, you are in the 60 to 90 grams per hour zone. Distribute it: one bar near the beginning of the hour, the second halfway through, and drink in small sips continuously.
The finale
If the intensity remains high in the last hour, a gel can be added for a quick peak. Not as a substitute for your rhythm, but as an extra. More on what works on a long tour is in the ideal snack for your bike ride.
Over a three-hour ride, you'll end up with 4 to 5 bars alongside your bottles. Always carry one more than your plan says. Supply stations are rarely where your body needs them.
Drinking and eating go together
Solid and liquid fuel work together. A sports drink with 6 to 8% carbs replaces fluids and provides part of your carbs. On a hot three-hour gravel day, you can easily lose 1.5 to 2 liters. Once you lose 2% of your body weight—about 1.4 liters for a 70 kg rider—your performance drops measurably.
By spreading your intake across two forms, your stomach handles it more calmly than if you ingest everything at once. Plan your bottles based on the route, not on assumptions. If you don't know where you can refill, start with two full bottles and the bars for the full duration.
BOOST: when caffeine is useful
The BOOST variant contains 50 mg of caffeine per bar, from a natural source. Where I use it: in the second half of a ride, when fatigue sets in and there are still technical sections ahead. Not at the start, and not as standard on every ride. What research says about caffeine and performance, including the dosages, is in caffeine, sport, and performance.
Contains caffeine. Not recommended for children, pregnant women, or caffeine-sensitive persons.
Fuel that is as serious as your ride
Gravel riders are stuck between two worlds. Not Sunday tourists, but not pros with a team dietitian in the following car either. Independent riders who choose their own equipment, plan their own training, and approach their nutrition just as consciously.
That is why I make what I make. Fruit pulp as a base, 2:1 as a ratio, no artificials, no colorings, no ingredients you have to look up. Anyone riding 80 km on unpaved roads deserves fuel that is as serious as the ride itself.
No gel. No brick. Fuel during exertion. Fuel your flight.
Scientific evidence
The 2:1 ratio boosts performance. After two hours of cycling, trained cyclists rode a time trial 8% faster on glucose and fructose in a 2:1 ratio than on glucose alone, and 19% faster than on water (Currell & Jeukendrup, 2008).
The mechanism behind it. The same ratio accelerates gastric emptying and fluid flow compared to glucose alone, making fuel available more quickly (Jeukendrup & Moseley, 2010).
Where the limit lies. During three hours of cycling, 90 grams of carbs per hour in a 2:1 ratio was the optimal dose. At 100 grams per hour, performance in the subsequent time trial decreased because the excess could no longer be absorbed (King et al., 2019).
References
Currell K, Jeukendrup AE (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine & Science in Sports & Exercise, 40(2), 275-281. doi:10.1249/mss.0b013e31815adf19
Jeukendrup AE, Moseley L (2010). Multiple transportable carbohydrates enhance gastric emptying and fluid delivery. Scandinavian Journal of Medicine & Science in Sports, 20(1), 112-121. doi:10.1111/j.1600-0838.2008.00862.x
King AJ, O'Hara JP, Arjomandkhah NC, et al. (2019). Liver and muscle glycogen oxidation and performance with dose variation of glucose-fructose ingestion during prolonged (3 h) exercise. European Journal of Applied Physiology, 119, 1157-1169. doi:10.1007/s00421-019-04106-9
Frequently Asked Questions
How many carbs do I need during an 80 km gravel ride?
Count on 60 to 90 grams of carbohydrates per hour, depending on intensity and how accustomed your stomach is to it. You get that from a combination of sports drink and solid fuel, not from one source. A 25-gram fruit performance bar provides 20 grams of carbs in a 2:1 ratio and fits into that schedule alongside your bottle.
How many bars do I eat per hour on gravel?
One to two per hour, alongside 500 to 800 ml of sports drink with 6 to 8% carbs. Together, this gets you to 60 to 90 grams per hour. More bars than that doesn't work: you can't chew them away on a technical course, and your stomach processes a spike less effectively than a spread-out intake.
When do I start eating during a gravel ride?
Within the first half-hour, before you feel hunger. On unpaved terrain, your exertion is higher than your speed suggests, because your upper body is working and your power output constantly fluctuates. If you wait until the hunger signal arrives, you are already riding with a deficit that you won't make up on the road.
What is the difference between glucose and fructose as fuel?
Glucose enters your blood via the SGLT1 channel in your gut wall, which is full at around 60 grams per hour. Fructose uses a separate channel, GLUT5. By combining both in a 2:1 ratio, you use two routes at once, and your absorption increases toward 90 grams per hour without the excess lingering in your gut.
Can I ingest more than 90 grams of carbs per hour?
You can ingest it, but you cannot absorb it. Research on three hours of cycling showed that 90 grams per hour was optimal and that 100 grams per hour lowered performance in the subsequent time trial. The excess remains in your gut and provides you with no extra energy, but does increase the risk of stomach problems.
Is the fruit performance bar suitable for gluten intolerance?
Yes. The bar is gluten-free, lactose-free, and vegan, with no artificials. For riders managing celiac disease or lactose intolerance, that is a difference compared to many classic bars, which often work on a wheat or milk basis.
When do I use the BOOST variant?
In the second half of a ride, when fatigue sets in and there are still technical sections ahead. BOOST contains 50 mg of caffeine per bar. Use it purposefully, not as a standard on every ride. Contains caffeine. Not recommended for children, pregnant women, or caffeine-sensitive persons.
