How many carbs per hour do you need cycling?
It depends on how long you ride and how hard — and, past a point, on what your gut has been trained to absorb, not on how much you weigh. The framework the sports-nutrition literature settled on (Jeukendrup, 2014) runs roughly 30 g/h for one to two hours, 60 g/h for two to three, and up to 90 g/h beyond that — for hard riding. Most rides are not hard riding. The table below scales that framework by intensity, which is the part the gel packaging leaves out:
| Ride intensity | 1 h | 2 h | 3 h | 5 h |
|---|---|---|---|---|
| Easy / recovery Full conversation, Zone 1–2 | 15 g/h | 30 g/h | 45 g/h | 45 g/h |
| Endurance All-day pace, upper Zone 2 | 25 g/h | 45 g/h | 70 g/h | 70 g/h |
| Tempo / group ride Working — short sentences, Zone 3 | 30 g/h | 60 g/h | 90 g/h | 90 g/h |
| Race / hard Sweet spot to threshold and above | 35 g/h | 70 g/h | 90 g/h | 90 g/h |
Grams of carbohydrate per hour for a rider used to gels and drink mix (90 g/h ceiling). New to eating on the bike, the ceiling is 60 g/h; gut-trained racers can push to 120. Computed by the calculator above.
Is 90 g/h necessary — or just a race number?
Here is the arithmetic nobody selling gels prints. A rider with a 250 W FTP on a two-hour endurance ride averages about 170 W and burns roughly 68 g of carbohydrate an hour — the rest of the energy comes from fat. Eating the table's 45 g/h, the shortfall over two hours is 46 g, drawn from the 400 g or so of usable glycogen a well-fed rider starts with. That's 12% of the tank. A banana and a bottle of mix cover it; 90 g/h would be paying for absorption you don't need.
Now race for three hours at 238 W. Carbohydrate's share of the energy climbs to three quarters and the burn rate hits 160 g/h — more than any gut can absorb. At 90 g/h in, the store still drains by 52%; stretch the race to five hours and it's 87%, with the last hour ridden on fumes. Drop to 60 g/h and the store runs dry after about 4.0 hours. That is what 90 g/h is for: long, hard days where burn outruns the tank. Enter your FTP above and the calculator runs this budget for your ride.
Glucose crosses the gut wall through one transporter (SGLT1) that saturates around 60 g/h — eat more plain glucose or maltodextrin and it sits in the stomach, which is where the nausea comes from. Fructose uses a different door (GLUT5), so a roughly 2:1 glucose-to-fructose mix adds another 30 g/h or more of capacity. That's the entire science behind "dual-source" products; table sugar (sucrose) is glucose and fructose bonded 1:1, which is why it works too.
What should you eat on a long ride?
Grams are grams. A 60 g/h plan over three hours is 180 g on paper; the ride plan above feeds 20 g every 20 minutes from minute 20 and skips the final 20 (nothing eaten then is absorbed before the finish), so you actually carry 160 g in 8 feeds — and here's what that looks like in each food alone, so you can mix and match from your own pockets:
| Food | Carbs per serving | For 3 h at 60 g/h |
|---|---|---|
| Energy gel | ~25 g | 7 |
| 500 ml bottle of drink mix | ~40 g | 4 |
| Banana | ~25 g | 7 |
| Energy bar | ~40 g | 4 |
| Rice cake / fig bar | ~30 g | 6 |
Typical values — read the label, especially for drink mix (a 500 ml bottle runs anywhere from 20 to 90 g depending on how you scoop). Solid food digests slower: real food early in the ride, gels and drink for the last hour and any hard sections.
How do you train your gut for more carbs?
The gut adapts like a muscle: transporter density and stomach tolerance rise with repeated exposure. Practice the race intake on long training rides, not on race day — start at the table's number, add 10 g/h every couple of weeks, and stay there when it stops feeling easy. Two other rules do most of the work: start eating in the first 20 minutes (the plan above does), because catching up on a deficit at hour three is how bonks happen; and use drink mix for a share of the carbs, since fluid empties from the stomach faster than solids. Riders who "can't eat on the bike" are almost always trying to eat too much, too late, too concentrated.
A 60 kg rider and a 90 kg rider on the same three-hour race get the same hourly target. Absorption is limited by intestinal transport, which doesn't grow with body mass; the bigger rider burns more total energy but draws more of it from a proportionally bigger glycogen store. Fluids are a different story — sweat rate does scale with size and heat, which is why the hydration calculator asks for your weight and this one doesn't.
Fueling before and after the ride
The plan above assumes you start full. For anything over two hours, that means normal carbohydrate-rich meals the day before and a meal two to three hours before rolling out — not a heroic pasta binge, just not skipping breakfast. Under 75 minutes the answer is that you need nothing during the ride; a swig of drink mix or even rinsing your mouth with it and spitting has a measurable effect on performance, but the tank comfortably covers the distance. Afterward, the recovery window is real but generous: carbs plus some protein within an hour or two, sized to how empty you got. A calories-burned number from real watts is the right guide to how much that is.