In long training sessions and races, performance often isn’t limited by your legs — it’s limited by your gut. Once glycogen stores run low, the decisive question becomes how much carbohydrate per hour you can take in and absorb. A good fuelling strategy during effort helps you hold your pace, avoid the sudden drop known as “the wall,” and reach the finish with something in reserve. This guide explains how many carbs you need per hour, why the glucose-to-fructose ratio matters, when to take a gel, and how to hydrate.
Why fuelling during effort matters
Your body stores carbohydrate as glycogen in the muscles and liver — but those stores only last around 60 to 90 minutes at intensity. Once they’re empty, blood sugar drops, your pace collapses and focus fades. Taking in carbohydrate during effort spares glycogen, keeps blood sugar stable and maintains power exactly when it matters most. The longer and harder the effort, the more decisive external fuel becomes.
How many carbs per hour?
Your needs rise with the duration of the effort. General guidelines:
| Effort duration | Recommended carb intake |
|---|---|
| up to 60–75 min | usually none needed (glycogen is enough) |
| 1–2.5 hours | 30–60 g/hour |
| 2.5–3 hours | 60–90 g/hour |
| very long efforts | up to 90–120 g/hour (with a trained gut) |
For short but intense efforts, a sip of an energy gel can support focus even before stores are depleted. For multi-hour rides and long runs, regular high intake is key. These figures are a starting point — actual needs depend on body weight, intensity and how well you’ve trained your gut. For a detailed breakdown, see our guide on how many carbs per hour of endurance effort.
The glucose-to-fructose ratio
Why can’t you simply take in 120 g of pure glucose per hour? Because your gut can’t absorb it. Glucose is carried by the SGLT1 transporter, which saturates at around 60 g per hour. Take more and the excess sits in the gut, causing bloating and distress.
The answer is fructose, carried into the blood by a different transporter (GLUT5). Using both pathways at once, the body absorbs far more carbohydrate per hour — with less stomach stress. The classic ratio was 2:1 (glucose:fructose) for up to 90 g/hour; modern products with a higher fructose share, such as a 1:0.8 ratio, allow up to 120 g of carbs per hour.
That’s the ratio WINFORCE uses. For the highest intake, CHO Maxxx is built for up to 120 g/hour; for a steady supply, Fast Energy and Carbo Basic Plus work well.
When and how often to take a gel
The most common mistake is waiting too long. Start fuelling early — within the first 20 to 30 minutes, not once you feel hunger or a drop in power. Once you hit the wall, a gel won’t fix it on the move.
Spread your fuel across regular, smaller doses: for example one gel every 30 to 45 minutes, with occasional sips of a carbohydrate drink in between. Take classic (non-isotonic) gels with some water; isotonic gels and drinks can be taken without.
For the final third of the effort, a caffeine energy gel adds an extra lift and sharpness.
Hydration and electrolytes during effort
Fuel doesn’t work without fluid. During effort you lose water and electrolytes (mainly sodium) through sweat. Aim for roughly 400–800 ml of fluid per hour, depending on heat, intensity and your sweat rate. Even a 2% drop in body weight from dehydration noticeably reduces performance.
For efforts longer than one to two hours, or in the heat, add electrolytes. Isotone supplies carbohydrate, minerals and fluid at once, Hydro Energy offers clean liquid energy, and Pure Electrolytes quickly replaces lost minerals.
Training your gut
Your gut’s ability to absorb carbohydrate isn’t fixed — it’s trainable. Practising your planned race fuelling in training increases transporter efficiency and helps you tolerate higher intake with fewer stomach problems. The golden rule: never try new fuel for the first time on race day.
A practical fuelling plan by duration
- ~1 hour, intense: 0–30 g carbs (a gel if the pace is high) plus sips.
- ~2 hours: ~60 g/hour (gel + carbohydrate drink), 500–700 ml fluid/hour.
- ~3 hours: 60–90 g/hour, add electrolytes.
- 5 hours+ / ultra: 80–120 g/hour (e.g. CHO Maxxx), regular electrolytes, caffeine in the final third.
Frequently asked questions
How many carbs per hour do I need for cycling or running?
For efforts up to 2.5 hours, typically 30–60 g/hour; for longer efforts 60–90 g/hour; and up to 120 g/hour on very long efforts with a trained gut.
Can I really take in 120 g of carbs per hour?
Yes, but only with a glucose-and-fructose mix (e.g. a 1:0.8 ratio) and a gut trained in advance. With pure glucose the limit is around 60 g/hour.
Should I take a gel with water?
Take classic gels with a little water for easier absorption; isotonic gels and drinks can be taken without extra water.
When should I use a caffeine gel?
Best in the final third of the effort or when focus drops.
Build your fuelling strategy
Start early, aim for 60–90 g of carbs per hour (up to 120 g on the longest efforts), use a glucose-to-fructose mix, and don’t forget electrolytes. Find everything for during effort in the Energy & Hydration category.
Related guides
General guidance; individual needs vary — test your strategy in training.
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