Cycling Ride Fuel and Calorie Planner
Carbohydrate, fluid and sodium per hour for a ride, the energy it actually costs, and how many gels or bars that means packing.
What to actually pack
| Item | Carbs each | How many |
|---|
Mix them rather than taking one thing. Palate fatigue is real on a long ride, and the person who packed six identical gels usually stops eating around hour three.
How much to trust these
- The energy figure is the solid part. Work in kilojoules is measured directly by a power meter, and because cycling efficiency sits near a quarter, kilojoules of work and kilocalories burned come out close to one to one.
- The carbohydrate figures are a starting point. Absorption has a ceiling that varies between people and rises with training — which is why 90 g an hour is a trained-gut number, not a default.
- Sweat rate and sodium vary enormously — by a factor of four or more between two riders in the same conditions. The sodium figure here is the middle of a very wide range and should not be treated as yours.
- Test it in training. Finding your gut's limit during a target event is a well-known way to end a target event.
How to use
- Enter how long you will be out and how hard you will ride.
- Set the temperature, which drives fluid more than anything else.
- Add your average power if you have a meter, or your weight if not.
- Read the per-hour figures, then check what that means in gels and bars.
Frequently asked questions
Why are kilojoules and calories almost the same number?
A coincidence worth knowing. A power meter measures mechanical work in kilojoules; converting to kilocalories divides by 4.184, and accounting for human cycling efficiency of roughly a quarter multiplies by about four. The two very nearly cancel, so a ride showing 1,400 kJ of work cost about 1,400 kcal. It looks like a mistake and is not.
Do I need to eat on a short ride?
Under about ninety minutes, no. Stored muscle glycogen covers it, and eating for a one-hour ride is a habit rather than a requirement. Longer than that and the guidance rises with duration rather than with effort, because the limit is how fast your gut absorbs rather than how fast your legs burn.
Why does 90 g an hour need both glucose and fructose?
Because glucose absorption saturates at around 60 g an hour — the intestinal transporter for it runs out of capacity. Fructose uses a different transporter, so a mixture moves more total carbohydrate across the gut wall. Products marketed on a 2:1 or 1:0.8 ratio are doing exactly this.
Is 90 g an hour safe to try in a race?
Not without practising it. The gut adapts to high carbohydrate intake over weeks of deliberate training, and attempting a trained-gut figure cold is a well-known way to spend an event by the roadside. Build up in training rides first.
How much should I drink?
The figure here scales with temperature, which is the dominant factor. Beyond that, drink to thirst rather than to a schedule — thirst is a reasonable guide for most people, and deliberately over-drinking carries its own risk of diluting blood sodium, which is genuinely dangerous and has killed endurance athletes.
How reliable is the sodium figure?
Least reliable of anything here. Sweat sodium concentration varies from roughly 200 to 2,000 mg per litre between individuals, a tenfold range, and the figure shown is the middle of it. If you finish rides with salt crusted on your face you are at the high end and this figure is low for you.
Why estimate energy from weight when I have no power meter?
Because it is the best available proxy — energy cost scales with the mass being moved and with how hard you are working. It is much less accurate than a power measurement, which is why the page says so rather than presenting the two as equivalent.
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