Fuel like you trained for it.
How many carbs per hour, when to take them, and the cheap swaps that actually work. From Coach Gene Convery, 20+ years coaching marathon and ultra runners and qualified endurance sports nutritionist.
Carbs per hour, by race length
Based on current sports nutrition guidelines for endurance events (e.g. Jeukendrup, 2014). These are ranges, not orders: your gut sets the ceiling, and training raises it.
Your race-day timeline
- 48–36 hrs outCarb load: 8–12g of carbs per kg of bodyweight per day, with an easy taper. Go low-fibre in the final 24 hrs.
- 2–4 hrs outBreakfast: 1–4g carbs per kg. Low fibre, low fat, low protein. Eat what you've rehearsed (toast + jam + banana + juice ≈ 100g).
- 15 min outOptional top-up: a gel, 3 snakes or a few jelly beans.
- From 20–30 min inStart fuelling before you feel you need it. Little and often: split your hourly target into 3 hits every 20 min.
- Every hourDrink to thirst, roughly 400–800ml per hour as a starting range. Hot day or salty sweater? Add sodium and test it in training.
- Post-raceCarbs + protein within the hour. This is where the Krispy Kreme lives.
Cheap swaps that actually work
Every one of these is roughly one gel's worth of carbs. Prices are Australian supermarket RRP, Oct 2026.
| Food | Serve | Carbs | Cost | Use it for |
|---|---|---|---|---|
| Squeezy honey | 30g (~1.5 tbsp) | 25g | $0.56 | Race-ready |
| Jelly beans | 13 beans | 25g | $0.76 | Race-ready |
| Coke (flat) | 250ml | 26.5g | $0.90 | Race-ready |
| Snakes Alive | 3 snakes | 28g | $0.94 | Race-ready |
| Tim Tams | 2 biscuits | 23.8g | $0.92 | Long slow runs |
| Mars bar | 1 bar (47g) | 33.3g | $2.20 | Ultra pace only |
| Typical gel | 1 gel | 25g | $6.00 | Race-ready |
Coach's call: mix both. Gels when it's hard (consistent dose, easy to get down at pace). Lollies, honey and flat Coke when it's long.
Train your gut: the ladder
Your gut adapts like your legs do. Climb roughly one rung every 1–2 weeks of long runs.
The five rules
- 1.Nothing new on race day. Not the gel, not the breakfast, not the flavour.
- 2.Fuel early. If you wait until you're hungry, you're already behind.
- 3.Fat and fibre late in a race = trouble. Save the treats for slow miles and the finish.
- 4.Gut shutting down? Slow down for 5 minutes, sip water, switch to liquid carbs.
- 5.Your numbers are personal. Test, write it down, adjust.
Want your exact numbers?
The ranges above get you started. Your real target depends on your race, pace, sweat rate and how trained your gut is. Plug yours into the free fuel planner, or let me build the whole plan with you.