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Carb loading
How much carbohydrate to eat in the days before a long race to start with full muscles.
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Carb loadingFondoLab
504
g carbs a day
- Days
- 2
- In total
- 1008 g
- Glycogen
- +22%
Eat at least 504 g of carbohydrate a day for the last 2 days before the race (7 g per kg). In the studies, loading like this left the muscles with about 22% more glycogen than a normal diet.
These are the lowest intakes the studies counted as loading, so read them as "at least". Try a loading day before a long training ride first: that much food takes some getting used to.
What moves it
- Spread over 5 meals and snacks
- 101 g
| Days | g/kg a day | A day | In total |
|---|---|---|---|
| 2 | 7 | 504 g | 1008 g |
| 3 | 6 | 432 g | 1296 g |
How we got this
The formula with your numbers in it, then every constant we used and where it comes from.
The working
- 7 g/kg × 72 kg = 504 g of carbohydrate a day, for 2 days
The numbers and their sources
A number marked FondoLab default is our judgement, not a study's finding; we say so rather than borrow authority.
| Number | Value | Basis |
|---|---|---|
| Carbohydrate loading | 7 g/kg a day for 2 days, or 6 g/kg for 3; resting glycogen about 22% higher | A meta-analysis of 181 studies defined high carbohydrate availability this way and found it raised resting muscle glycogen by 102 mmol/kg, from a normal 462. These are the thresholds it used, so read them as "at least". [1] |
References
-
Areta JL, Hopkins WG (2018). Skeletal muscle glycogen content at rest and during endurance exercise in humans: a meta-analysis. Sports Medicine 48(9):2091–2102. doi:10.1007/s40279-018-0941-1
Meta-analysis · 181 studies of healthy people cycling or running, with glycogen measured in muscle biopsies, mostly from the thigh (vastus lateralis). · Read by us: Abstract
Pooled muscle glycogen at rest and during exercise, and what changes it.
- At rest, the thigh muscle of men with a normal diet and a VO2max around 53 mL/kg/min held 462 ± 132 mmol per kg of dry muscle.
- High carbohydrate availability, defined as at least 6 g of carbohydrate per kg of body weight per day for 3 days or more, or at least 7 g/kg/day for 2 days or more, raised resting glycogen by 102 mmol/kg (a moderate effect, ± 47).
- A glycogen-depleting low-carbohydrate diet lowered it by 253 mmol/kg. Ten mL/kg/min more VO2max added 29–80 mmol/kg, depending on diet.
- During exercise, harder riding used more glycogen, and a rider who started with more glycogen used more of it on long efforts.
Read more: How many carbs per hour on a gran fondo?
60, 90 or 120 grams an hour? What the research says about carbohydrate on long rides, and how to set your own target.
On your race
Fueling planner: carbs, fluid and caffeine stop by stop for your race
More calculators
- Energy of an effortWatts and time to kJ of work and kcal burned, with the gross efficiency it rests on.
- Carbohydrate budgetMuscle and liver glycogen against what a ride burns: when you run empty, and what to eat or how much to ease off.
- Caffeine doseCaffeine in mg for your body weight: the dose that helps endurance, and EFSA's safe limits.