Carbohydrate & fluids
Race fuel planner
How much carbohydrate per hour for your race, a schedule for the gels or drink you use, and a fluid check from your own sweat.
Your fuel plan
Your target per hour
60 g/h
Longer than 2.5–3 hours: up to 90 g per hour, best from products that mix glucose and fructose.
- Every
- 25 min
- Gels
- 9 × 25 g
- Total
- 225 g
- Average
- 56 g/h
| # | Take at (h:mm) | Carbohydrate so far |
|---|---|---|
| 1 | 0:25 | 25 g |
| 2 | 0:50 | 50 g |
| 3 | 1:15 | 75 g |
| 4 | 1:40 | 100 g |
| 5 | 2:05 | 125 g |
| 6 | 2:30 | 150 g |
| 7 | 2:55 | 175 g |
| 8 | 3:20 | 200 g |
| 9 | 3:45 | 225 g |
Fluid check
Aim to lose less than
1.4kg
2% of your weight: 1.4 kg (3.1 lb)
- Sweat lost
- 1.30 L
44 fl oz - Sweat rate per hour
- 1.30 L
44 fl oz - Weight change
- −1.1%
You stayed within 2% of your body weight on this run.
Where the numbers come from
The ranges come from the joint position stand of the American College of Sports Medicine, the Academy of Nutrition and Dietetics and Dietitians of Canada:
- Under 45 minutes: not needed.
- 45–75 minutes: small amounts, including a mouth rinse.
- 1–2.5 hours: 30–60 g per hour.
- Longer than 2.5–3 hours: up to 90 g per hour, best from products mixing glucose and fructose.
The schedule spaces your products evenly to meet the target, and stops before the finish. Both sources stress practising your plan in training, so your stomach is used to it on race day.
Fluids
Aim to finish having lost less than about 2% of your body weight, but never drink more than you sweat: overdrinking is the main cause of hyponatraemia, a dangerous fall in blood sodium, and recreational runners, who sweat less than elite ones, are the most likely to overdrink. A typical plan works out at 0.4–0.8 litres per hour, adjusted to your own sweat rate; each kilogram lost is roughly a litre of sweat.
Sources
- Carbohydrate during exercise (Table 2), fluid plans of 0.4–0.8 L/h, 1 kg ≈ 1 L of sweat, and hyponatraemia: Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 48(3), 543–568 (2016).
- Up to about 90 g per hour from glucose and fructose mixes, and practising intake in training: Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine 44 (Suppl 1), S25–S33 (2014); published in a supplement supported by the Gatorade Sports Science Institute.
- Keeping losses under 2% of body weight and weighing before and after exercise: Sawka MN et al. American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine & Science in Sports & Exercise 39(2), 377–390 (2007).
Questions
How many gels do I need for a marathon?
It depends on your finish time, the gel and your target. At 60 g per hour with 25 g gels, a 4-hour marathon means one every 25 minutes, nine in all.
Why does the target stop at 90 g per hour?
That is the top of the published guidance for events over 2.5–3 hours. For races under 2.5 hours the limit is 60 g.
How do I find my sweat rate?
Weigh yourself before and after an hour’s run in similar weather to race day, and note what you drank. The fluid check turns that into litres per hour.