Reviewed for accuracy: This article references the published research of Prof. Asker Jeukendrup on carbohydrate oxidation and multiple-transportable-carbohydrate formulations, and the practical protocols used by Dr. David Dunne and Alan Murchison with World Tour and amateur athletes. The intake bands described are training and performance targets, not medical recommendations. Riders with diabetes, gut conditions or other clinical concerns should consult a sports dietitian.
The carbohydrate-per-hour question is the single most-asked nutrition question in amateur cycling, and the most consistently answered with the wrong number. The reflexive answer — "90g per hour" — is correct for one situation. It is too high for most rides, too low for some, and useless without context.
The honest target depends on three variables: how long the ride is, how hard it is, and whether your gut is trained for the intake you are aiming at. Get all three right and the number takes care of itself. Get any one of them wrong and the prescription falls apart.
This is the framework used inside the Roadman coaching programme and the in-ride fuelling calculator, built on Asker Jeukendrup's published research and the practical protocols Dr. David Dunne and Alan Murchison have walked through on the podcast.
The short answer in a table
| Ride duration & intensity | Target | Format | |---|---|---| | <60 min, any intensity | 0-30g/hr | Optional; water often enough | | 60-90 min, easy | 30-45g/hr | Drink mix or single gel | | 60-90 min, hard | 45-60g/hr | Drink mix + 1 gel | | 90 min - 2 hr, hard | 60-75g/hr | Drink mix + gels | | 2-3 hr, race intensity | 75-90g/hr | 2:1 glucose-fructose, mixed sources | | 3 hr+, sportive/race | 90-120g/hr | Trained gut required, mixed sources | | 5 hr+, ultra | 60-90g/hr (varies) | Mixed sources, savoury food included |
Every band assumes a 2:1 glucose-to-fructose ratio above 60g per hour and gut training appropriate to the target. The bands are training and racing targets, not floors below which performance collapses.
Why a single number is wrong
The body's capacity to oxidise carbohydrate during exercise has clear physiological limits. The standard data, from Jeukendrup's lab work and the meta-analyses that followed it, looks like this:
- Pure glucose: oxidation peaks at approximately 60g per hour, limited by the SGLT1 intestinal transporter.
- Glucose + fructose at 2:1: oxidation reaches approximately 90g per hour, using SGLT1 (glucose) and GLUT5 (fructose) in parallel.
- Trained gut + multiple transporters: 100-120g per hour is achievable, and elite athletes regularly exceed this in racing.
These numbers are upper bounds on absorption and oxidation. They are not minimum requirements. A two-hour zone 2 ride does not need 90g of carbohydrate per hour. A six-hour mountain stage in a Grand Tour does. The right intake is the one that matches the demand.
The error most amateurs make is to copy the headline number from World Tour racing — "Tadej Pogačar eats 120g of carb per hour" — and apply it to a Sunday endurance ride. Two things go wrong. The intake is unnecessary for the stimulus and produces gut load with no benefit. And eating that volume of carbohydrate on every ride suppresses the fat oxidation adaptations that long endurance work is supposed to produce.
The opposite error is more common still: under-fuelling hard rides that genuinely warrant 90g per hour, finishing depleted, and writing it off as a fitness problem.
Setting your number by ride
The question to ask before any ride is not "how many carbs per hour" but "what is the energy demand of this session and how much of it should come from on-bike intake?"
Recovery rides and short zone 2 (under 60 minutes). Carbohydrate intake is optional. Water is often enough. If the morning's breakfast has been adequate, the body has no problem covering a 45-minute aerobic ride from glycogen and fat. Eating a gel on a recovery ride is rarely wrong and rarely necessary.
Mid-week endurance (60-90 minutes, mostly zone 2). 30-45g per hour from a single bottle of mild drink mix is enough. The point of these rides is aerobic adaptation and the maintenance of training capacity, not maximum performance. Over-fuelling them blunts the fat oxidation stimulus that makes them valuable.
Long zone 2 ride (2-4 hours). 45-60g per hour is the sweet spot. Enough to keep blood glucose stable and the central nervous system fed; not so much that you suppress the aerobic system the ride is meant to train. A bottle of sports drink mix per hour and a banana or small bar at the halfway point covers it.
Hard interval session (60-90 minutes including warm-up and cool-down). 60-90g per hour, weighted toward the work intervals themselves. Most coaches will recommend a gel before the second or third interval and a drink mix bottle to sip across the session. Under-fuelling intervals does not make them more productive — it makes them less.
Sportive or race effort (3-6 hours, sustained hard). 80-120g per hour, depending on gut tolerance and product formulation. The full breakdown is in the 100-mile sportive nutrition plan. The principle is consistent: front-load the intake, mix sources, ramp down only when conditions demand.
Ultra-distance (>6 hours). 60-90g per hour during sustained efforts, dropping to 40-60g per hour during low-intensity overnight sectors. Above six hours, gut tolerance is the limit, not transporter capacity. The full ultra protocol — including the sleep-fuelling interaction — is in the Badlands fuelling breakdown.
Why 90g/hr is the practical ceiling for most amateurs
The 120g per hour figure that has become headline news from professional cycling is a real number, but it is a trained capacity, not a default. Three things are happening when a Tour de France rider eats 120g per hour reliably:
- Years of progressive gut training. The intestinal transport capacity adapts to repeated high carbohydrate exposure during exercise. The same volume that causes GI distress in an untrained gut is comfortably tolerated in a trained one.
- Specific product formulations. High-osmolality drinks, dual-source gels with optimal glucose-to-fructose ratios, and pacing of intake to avoid bolus-induced spikes. The product matters as much as the volume.
- Hot climate adaptation. Pro racers in summer have adapted to drink and eat in heat. Hot conditions impair gut function, and a rider who has not done specific heat training will hit gut limits faster than the calorie target predicts.
For most amateur cyclists, 90g per hour is a sound performance ceiling. It is achievable with off-the-shelf products. It produces oxidation rates close to the absorption maximum. It tolerates the gut without specific training in most riders who have ramped to it across a build phase.
The riders who push beyond 90g per hour and feel the benefit are typically those competing in long, hard events — multi-day stage races, ultra-endurance events, or hilly sportives where energy demand is genuinely beyond what 90g per hour can cover. For a 100-mile sportive at 17 mph, 90g per hour is plenty. For a 12-hour ride in heat, the ceiling matters more.
Gut training: the bit no one wants to do
The honest reason most cyclists cannot eat 90g per hour comfortably is not that they need a different product. It is that they have not trained the gut to absorb it.
The gut adapts to the load you place on it, in the same way the cardiovascular system adapts to training. The transporter density increases. Gastric emptying improves. Tolerance to carbohydrate concentration rises. None of this happens if you fuel every training ride at 40g per hour and expect to hit 90g per hour on race day.
The protocol that works:
- Weeks 1-2: Identify your current comfortable intake, typically 50-60g per hour for someone who has not trained the gut deliberately. Use long training rides at race-pace effort to test it.
- Weeks 3-4: Add 10g per hour. Use the actual products you intend to race with. Repeat across two to three long rides per week.
- Weeks 5-6: Add another 10g per hour. Adjust formulation if GI distress appears — a more dilute drink, a different gel, a switch to bar-and-drink instead of gel-and-drink.
- Weeks 7+: Continue ramping until target intake is comfortable. Most amateur cyclists reach 90g per hour reliably across an 8-12 week ramp.
The non-negotiables: use real long rides, not short tests; use the products you plan to race with; back off any week where GI symptoms exceed mild bloating. The point is to teach the gut to handle the load, not to suffer through it.
When the maths breaks: heat, intensity, gut state
Three real-world conditions disrupt the standard intake bands.
Heat. Riding in conditions above roughly 28°C reduces gastric emptying rate and pushes more cardiac output to skin blood flow. The same intake that is comfortable at 18°C may cause distress at 32°C. Drop carbohydrate by 10-15g per hour in hot conditions and add sodium and water. Heat acclimation across 10-14 days reduces but does not eliminate this effect.
Very high intensity. Sustained efforts above approximately 85 per cent of FTP push gut function down. Gels and drink mix tolerate; solid food typically does not. In a hard interval session or race scenario, lean entirely on liquid carbohydrate and gels in the hot phase, then add solid food when intensity drops.
Gut state on the day. Sleep deprivation, recent travel, stomach bug, antibiotics, or a meal that did not agree all reduce gut tolerance. The intake number is not a guarantee — it is a target that assumes baseline gut function. If the gut is compromised on the day, drop intake by 20-30 per cent and accept the lower performance ceiling. Forcing food when the gut refuses ends races.
Practical tools for the right number
Two tools do most of the work:
The in-ride fuelling calculator takes ride duration, body weight and target intensity and produces an hourly carbohydrate target plus an estimated fluid and sodium target. It is the simplest way to convert an event into a carb target without doing the maths every time.
The race weight tool and energy availability tool sit on the other side of the equation — what your daily intake needs to be to support your training load. Under-eating across the week and trying to hit 90g per hour on race day rarely produces the result you want.
For the full event-specific application, NDY coaching at Roadman writes the fuelling plan into the training plan as one document, with progressive gut training built into the long rides across the weeks before the target event. The application is where the conversation starts. Carbohydrate per hour is not a number to memorise. It is a target to build towards, with the rest of the system pulling in the same direction.
If you've got a specific question — your own per-hour target for a heat-affected sportive, whether to push past 90g/hour for an ultra, or what to do when products keep upsetting the gut — ask Roadman for an answer drawn from the actual conversations with Asker Jeukendrup, Dr. David Dunne, Alan Murchison, and the rest of the nutrition guests.