What do I eat before my marathon?

What do I eat before my marathon?

Apr 16, 2025

Are you planning to run a marathon soon? Perhaps for the first time, with the goal of completing the magical distance of over 42 km? Or are you looking for the last few extra percent to improve your personal record? It goes without saying that good preparation is half the battle. You will undoubtedly have thought of the right footwear and sufficient training, but do you also have a well-thought-out competition nutrition plan ready? In this blog we describe what, how much and when you should eat in the run-up to your marathon, so that you can start with a full fuel tank.

In terms of nutrition, the final preparation for the marathon begins about 36 to 48 hours before the start. The last 1 to 2 days before the marathon should be dedicated to stacking carbohydrates ('carbo loading'). Longer than 1 to 2 days is pointless! Scientific research has shown that stacking carbohydrates ensures a larger glycogen supply in your muscles. This supply is the most important source of energy during the marathon. Carbohydrate stacking gives you a significant head start.

To make this process run optimally, aim for 8 to 10 grams of carbohydrates per kilogram of body weight per day in the last two days before the marathon. For someone weighing 70kg, this means 560 to 700 grams of carbohydrates per day. It is recommended to spread this over 3 meals and 2 to 3 snacks. More practical tips for carbohydrate stacking can be found in the blog about this. A daily example for someone weighing 70kg can be seen here:

 


CARBOHYDRATE LOADING: EXAMPLE FOR 70KG
Meal Products Amount Carbohydrates (g)
Breakfast White bread rolls 3x 55
Fruit sprinkles 3x 40
Low-fat fruit yogurt 200 ml 20
Fruit juice 1 glass (250 ml) 30
Morning snack Soft drink 1 can (330 ml) 30
Ripe banana 1x 30
Lunch White sandwiches 6x 100
Chicken fillet/ham/roast beef 3x 0
Jam/honey/fruit sprinkles 3x 40
Fruit juice 1 glass (250 ml) 30
Afternoon snack Fruit yogurt with muesli 250 ml + 40 grams 75
Banana 1x 30
Dinner White pasta or rice 175 grams (uncooked) 110
Chicken fillet 120 grams 0
Vegetables 200–250 grams 10–20
Evening snack Low-fat fruit yogurt 250 ml 30
Soft drink 1 can (330 ml) 30
Total 665

 

After you have stacked your carbohydrates in the above manner, you only need to replenish the last bits of carbohydrates in your body on the morning of the marathon. Therefore, aim for about 3 grams of carbohydrates per kilogram of body weight for breakfast. For someone weighing 70 kg, this amounts to +- 210 grams of carbohydrates. To ensure that all of this is digested and absorbed before the start of your race, and thus prevent stomach/intestinal complaints, it is recommended to have breakfast at least 3 to 4 hours before the start. Preferably choose easily digestible products (such as white bread, cornflakes or rice pudding) and possibly fill with liquid sugars (such as honey, jam and fruit juice). Avoid products that contain a lot of fats and/or proteins, such as eggs, (full-fat) dairy, cheese and meat products. Also, don't forget to drink plenty. Aim for at least 500 ml of fluid, but above all check the colour of your urine. This should be relatively light in colour, to ensure that your fluid balance is in order. See an example below:



Marathon runner of 70kg (goal = approx. 210 grams of carbohydrates)

Food Item Carbohydrates
4 white bread rolls with jam, syrup, or fruit sprinkles 135 grams of carbohydrates
Bowl of fruit yogurt (200g) 25 grams of carbohydrates
30 grams of cornflakes 25 grams of carbohydrates
1 glass of fruit juice (200ml) 25 grams of carbohydrates
Total 210 grams of carbohydrates


In summary:

  • Start loading carbohydrates 1 to 2 days before the marathon. The starting point is approximately 8 to 10 grams of carbohydrates per kilogram of body weight per day.
  • Preferably divide this large amount of carbohydrates over 3 meals and 2 to 3 snacks per day.
  • Provide a carbohydrate-rich and easily digestible breakfast about 3 to 4 hours before the start. The starting point is approximately 3 grams of carbohydrates per kilogram of body weight.
  • Choose easily digestible products, possibly supplemented with liquid sugars.

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