Fuel the work, not the worry
Evidence-led carbohydrate, fluid and recovery numbers for long rides, runs and races — translated from sports-science into a plan you can put on a plate (or in a bottle) today.
How much carbohydrate per hour?
Carbohydrate need scales with how long you're out there — not with how heavy you are. Below ~75 minutes you can often run on what's already in the tank; beyond that, top up. The very top end (90g/hr) is only realistic with multiple carb sources (glucose + fructose) and a gut you've trained for it.
Usually no fuel needed — water is plenty
A small top-up or a mouth rinse can help
30–60g/hr; a single source can cover this
Lean on glucose + fructose mixes
Only with a trained gut and split sources
Fuelling around a long ride or run
A worked example for an effort of roughly 3+ hours. Adjust the clock to your event, and rehearse it in training — race day is never the time to try something new.
- –3 hr
Pre-event meal
A familiar, carb-rich meal (porridge, toast and honey, rice) with a little protein and low fibre/fat to settle the gut. Aim for roughly 1–2 g carbs per kg body weight.
- –30 min
Top-up & hydrate
A small carb snack (banana, gel, a few dates) and 300–500ml of fluid with a pinch of sodium. Sip, don't gulp.
- 0:00
Start steady
Begin fuelling early — before you feel empty. Waiting until you bonk means playing catch-up your gut can't win.
- Every 20–30 min
Drip-feed carbs
Take regular small amounts to hit your 30–90 g/hr target. Little and often beats one big hit that sloshes in the stomach.
- Each hour
Fluid & sodium
Sip 400–800ml/hr to taste and conditions, with 300–1,000mg sodium/hr if you're a salty or heavy sweater. Match thirst — over-drinking plain water risks hyponatraemia.
- 0–30 min after
Open the recovery window
A carb-and-protein snack plus fluids and a little salt within the first half-hour kick-starts glycogen replenishment and repair.
- +2–4 hr
Proper recovery meal
A balanced plate: ~1.0–1.2 g carbs/kg to refill stores, 20–40g quality protein for muscle repair, plus colour and fluids.
A worked recovery meal
One practical post-session plate for a ~70 kg athlete — think a generous bowl of rice or potatoes, a palm of salmon or tofu, and plenty of veg. Carbohydrate leads (to refill glycogen), protein supports repair, and a little fat is fine. Numbers are illustrative; scale carbs to your body weight (~1.0–1.2 g/kg).
per recovery plate, ~70 kg athlete
Why 90g/hr isn't a free pass
The headline ultra-endurance figure — around 90 grams of carbohydrate an hour — gets quoted a lot, but it comes with caveats. It only works with multiple transportable carbohydrates (glucose paired with fructose), because a single source maxes out near 60g/hr no matter how much you swallow. The rest just sits in your gut and causes trouble.
Reaching the top end also takes practice. Gut training — gradually nudging your in-session carbs up over weeks — improves tolerance and reduces (though rarely eliminates) GI distress. Most people racing for one to three hours never need to chase 90g; a comfortable, well-rehearsed 60g/hr is the quiet winner.
Common fuelling questions
How many carbs do I actually need per hour?
It depends on duration, not body weight. For efforts of one to two and a half hours, aim for 30–60g of carbohydrate per hour. Beyond two to three hours you can push toward 60–90g/hr, but the very top end needs split carb sources (glucose + fructose) and a trained gut. Under about 45–75 minutes, water is usually all you need.
How much should I drink?
Most people can absorb roughly 400–800ml of fluid per hour, and few manage more than a litre. The best guide is your own sweat rate: aim to replace around 80–100% of what you lose, and let thirst lead. Over-drinking plain water on long days can dilute your blood sodium (hyponatraemia), which is dangerous — so don't force fluids.
Do I need electrolytes, or is water enough?
For short or cool sessions, water is fine. For longer or hotter efforts — especially if you're a salty or heavy sweater — adding sodium helps. Losses commonly run 400–1,800mg of sodium per hour, and consuming 300–1,000mg+ per hour supports performance and lowers hyponatraemia risk. Potassium, magnesium and calcium round out what's lost in sweat.
What's the best recovery meal?
Think carbs to refill, protein to repair, fluids and a little salt to rehydrate. A practical target is roughly 1.0–1.2g of carbohydrate per kg of body weight in the four hours after exercise, alongside 20–40g of quality protein. A snack within the first 30 minutes opens the window; a proper balanced meal a couple of hours later does the heavy lifting.
Should I 'train low' or always fuel up?
Both have a place, but they're different tools. Occasional lower-carb training can nudge fat-adaptation; key sessions and races almost always go better fully fuelled. As a rule of thumb: rehearse your race fuelling in your long sessions, and don't experiment with anything new on event day.
Build a fuelling plan that fits your event
Whether it's a first half-marathon or a multi-day tour, the principles are the same — start early, drip-feed, hydrate to your sweat rate, and recover deliberately. If you'd like help tailoring the numbers to you, the Dietitian Without Borders team is here.