Under 45–60 minutes: water is usually enough. From roughly 1 to 2.5 hours: aim for about 30–60 g of carbohydrate per hour. Past 2.5–3 hours, especially at race intensity: many athletes push toward 60–90 g/hour, split across more than one carbohydrate source. The exact number still depends on your sport, your gut's training, and the conditions.
Why fueling during exercise matters
Your body stores enough carbohydrate (as muscle and liver glycogen) to fuel roughly 60–90 minutes of moderate-to-hard effort before those stores start running low. Past that point, blood glucose becomes a bigger share of what your muscles are burning, and if you're not topping it up, effort starts to feel harder than it should for the same pace or power. That's the "wall" or "bonk" endurance athletes talk about, and it's largely a fuel-supply problem, not just a fitness one.
How much carbohydrate per hour, by duration
There's no single right number, but the shape of the guidance is consistent across endurance sports:
- Under ~45–60 minutes: glycogen stores usually cover it. Water, maybe a mouth rinse with a carb drink for very hard efforts, is typically enough.
- ~1–2.5 hours: around 30–60 g of carbohydrate per hour is a common starting range.
- 2.5–3+ hours, or high intensity for that long: up to 90 g/hour, using more than one type of carbohydrate at once.
These are ranges, not targets to hit exactly. Body size, intensity, heat, and how well-practiced your gut is all shift where you should sit within them — which is exactly the kind of adjustment a fixed rule of thumb can't make for you, but a session-specific plan can.
Why multiple carbohydrate sources let you go higher
Glucose alone (the sugar in most sports drinks and gels) can only be absorbed by your gut at a limited rate, generally capping out around 60 g/hour no matter how much more you eat. Fructose is absorbed through a different pathway, so combining glucose and fructose — commonly in roughly a 2:1 ratio — lets your gut take up more total carbohydrate than either sugar alone. That's the reasoning behind "dual-source" or "multiple transportable carbohydrate" products, and why very long or hard efforts often call for reading the ingredients list, not just the grams-per-serving number.
Fluids and electrolytes alongside carbs
Carbohydrate and fluid are two separate problems that happen to arrive in the same bottle. For most sessions under about two hours in mild conditions, matching your normal thirst with water is fine. As duration, heat, or your personal sweat rate go up, sodium replacement starts to matter more — and it's worth planning independently of your carb target, since a drink strong enough to hit your carb number isn't automatically the right concentration for your fluid or sodium needs too.
Training your gut to handle more
Gut tolerance for carbohydrate during exercise responds to practice, the same way aerobic fitness does. Athletes who repeatedly train at or near their target intake — not just on race day — reliably tolerate more carbohydrate with less GI distress over weeks of practice. If you're planning to push toward the higher end of the range for a big event, rehearse it in training first, not for the first time on the day that matters.
Food, gels, and drinks: picking a mix
Gels are convenient and dense but not mandatory. Real food (bananas, rice cakes, dates), chews, bars, and sports drinks all count toward your carbohydrate total, and mixing formats is often easier on the stomach than relying on one texture for hours. What actually matters for the fueling target is total grams of carbohydrate per hour and how well you tolerate the source — not whether it came from a wrapper or a kitchen.
Common mistakes
- Waiting until you feel it. By the time you feel low on energy, you're already behind — fueling works better on a schedule than a feeling.
- Trying a new product on race day. Any new fuel — new brand, new format, new dose — belongs in training first.
- Chasing a single generic number. "60 g/hour" said to every athlete regardless of duration, sport, or gut training is a starting guess, not a plan.
- Ignoring fluids and sodium because the carbs are handled. They're related but separate targets.
Putting it into a plan
The ranges above are a genuinely useful starting point, but they're still ranges — the honest answer to "how much should I eat during my ride" depends on your sport, your goal for that specific session, your weight, the duration, and the route. That's the actual problem Fuel Snapshot is built to solve: it takes those inputs and turns them into a specific target and a timed schedule of what to eat and when, instead of leaving you to interpolate a range on the fly mid-session.