Carb Loading Chart: Grams of Carbs per Day by Body Weight
Daily carbohydrate targets for the 1–3 days before a race, using the same g/kg figures as the calculator above (marathon 10 g/kg, half marathon 8 g/kg, 10K 6 g/kg). Find your body weight in the left column.
| Body weight | Marathon (42.2K) (g/day) | Half Marathon (21.1K) (g/day) | 10K (g/day) |
|---|---|---|---|
| 50 kg (110 lbs) | 500 g · 2000 kcal | 400 g · 1600 kcal | 300 g · 1200 kcal |
| 55 kg (121 lbs) | 550 g · 2200 kcal | 440 g · 1760 kcal | 330 g · 1320 kcal |
| 60 kg (132 lbs) | 600 g · 2400 kcal | 480 g · 1920 kcal | 360 g · 1440 kcal |
| 65 kg (143 lbs) | 650 g · 2600 kcal | 520 g · 2080 kcal | 390 g · 1560 kcal |
| 70 kg (154 lbs) | 700 g · 2800 kcal | 560 g · 2240 kcal | 420 g · 1680 kcal |
| 75 kg (165 lbs) | 750 g · 3000 kcal | 600 g · 2400 kcal | 450 g · 1800 kcal |
| 80 kg (176 lbs) | 800 g · 3200 kcal | 640 g · 2560 kcal | 480 g · 1920 kcal |
| 85 kg (187 lbs) | 850 g · 3400 kcal | 680 g · 2720 kcal | 510 g · 2040 kcal |
| 90 kg (198 lbs) | 900 g · 3600 kcal | 720 g · 2880 kcal | 540 g · 2160 kcal |
| 100 kg (220 lbs) | 1000 g · 4000 kcal | 800 g · 3200 kcal | 600 g · 2400 kcal |
Multiply the daily figure by the number of loading days for your total. A 70 kg marathoner loading for 2 days needs about 1400 g of carbohydrate in total, which is why low-fibre, easy-to-eat foods such as white rice, bagels, juice and sports drink do most of the work.
What Is Carb Loading?
Carbohydrate loading (glycogen supercompensation) is the practice of eating a high-carbohydrate diet in the 1–3 days before an endurance race. The goal is to maximise the amount of glycogen stored in your muscles and liver — your primary fuel source during race-pace running. For a complete overview of race-week fuelling, see our marathon nutrition guide.
A typical runner stores roughly 400–600g of glycogen when fully loaded. This provides approximately 1,600–2,400 calories of quickly accessible fuel — enough for 90–120 minutes of race-pace running. For a marathon, which takes most recreational runners 3–5 hours, this means you'll need to top up with mid-race nutrition even with optimal loading.
How Much to Eat: The Science
Sports nutrition research recommends 8–12g of carbohydrate per kg of body weight per day during the loading phase:
- Marathon: 10g/kg/day for 2–3 days
- Half marathon: 8g/kg/day for 1–2 days
- 10K: 6g/kg/day for 1 day (or simply a high-carb dinner the night before)
For a 70 kg runner, a full marathon loading protocol means consuming 700g of carbohydrate per day — approximately 2,800 calories from carbs alone. This requires deliberate meal planning and intentionally reducing fat and protein intake to make room for carbohydrates.
What to Eat (and Avoid) During Loading
Best carb loading foods: white rice, white pasta, white bread, bagels, oats, potatoes (without skin), sports drinks, bananas, orange juice, honey, rice cakes, breakfast cereals (low-fibre).
Avoid during loading days:
- High-fibre foods (wholegrain bread, lentils, beans, raw vegetables) — increase GI risk
- High-fat foods (oils, butter, cheese, fatty meats) — slow glycogen storage and are calorically dense without helping loading
- New or unfamiliar foods — never experiment the night before a race
- Alcohol — impairs glycogen synthesis and disrupts sleep
Race Morning Breakfast
The morning of the race, eat a high-carbohydrate, low-fat, low-fibre breakfast 2–4 hours before the start:
- White toast or a bagel with jam or honey (no butter)
- Oats with banana and a teaspoon of honey
- White rice or pasta if your stomach tolerates it
- Sports drink alongside water
- Avoid: eggs, bacon, high-fat yogurt, any new food, high-fibre muesli
If you're running early and can't eat 2–4 hours beforehand, a small easily digestible snack 60–90 minutes before (banana, white toast, sports gel) is better than nothing.
Mid-Race Fuelling
Even with optimal carb loading, you'll need mid-race nutrition for a marathon. Take a gel or sports drink every 45 minutes from the 15 km mark onwards. Missing fuelling windows is the #1 cause of the marathon wall — your loaded glycogen stores don't last the full 42 km at race pace. Once your nutrition is dialled in, use the marathon pace calculator to plan your race-day splits, and see the full marathon training guide to structure your build.