Competition General Nutrition Training

Nutrition and marathon preparation 

In order to prepare for a marathon and be ready on day x, it is necessary to plan well in advance a suitable training plan, and to put it into practice in the months leading up to the event.  

A good diet is an integral part of this training plan, and also essential to be able to finish the 42,195 km without cramps, energy loss or injury. Let’s discover in this article the ideal nutritional plan to follow the two weeks before the marathon.  

The runner’s nutrition

The importance of nutrition increases with the progression of training. This must be in line with factors such as training volume, goals and individual stimuli. In general, the amount of training increases in the months leading up to a marathon, and these additional kilometres imply a higher calorie demand on the body. Therefore, it is important to also take regenerative measures on the nutrition side in order to recover optimally from the hard training sessions. These measures consist of replenishing carbohydrate reserves, compensating for the water deficit and a sufficient supply of protein. 

The runner’s diet must be varied, complete and constant. The basic nutrients must always be guaranteed, and be careful not to expose your body to abrupt dietary changes. In addition, it is obviously essential to hydrate a lot (in the two weeks before the race, you can slightly increase the quantities throughout the day). You can find other interesting articles on hydration here:


Each nutrient plays a fundamental role for the athlete, but with different tasks. The main ones are as follows:

  • Carbohydrates: Carbohydrates or glucides are the basis of an athlete’s diet, as they are the primary source of energy, and are therefore essential before and during activity to meet immediate energy needs, and after sport to replenish glycogen stores.
  • Protein: Protein is needed to maintain muscle mass, and it should be present in adequate quantities every day.
  • Fats: Fats complement a balanced diet; they are indispensable for blood clotting and the proper functioning of the cardiovascular and immune systems. In low-intensity sports they are also used as a source of energy.

Important nutritional tips

Here are some nutrition tips to follow in the weeks leading up to a marathon:

  • First of all, lets discuss carbohydrates, the marathon runner’s main source of energy. Planning a carbohydrate-based diet is certainly a good strategy, as they have the ability to saturate the body’s glycogen reserves, creating an effect on muscle performance and thus delaying fatigue. The closer you get to day x, the more important carbohydrate intake becomes. If you do not replenish your reserves, you run the risk of running into the famous ’30 km wall’, i.e. the last quarter of the race when your energy drops dramatically.
  • Particularly in the two weeks before the event, we recommend consuming foods rich in potassium (oranges, bananas, tomatoes, legumes, beetroot) and magnesium (seeds, leafy vegetables, lentils, whole grains, tofu, yogurt). These nutrients ensure optimal cardiac function, help to cope with muscular exertion properly and contribute to the proper functioning of various metabolic processes.
  • A minimum intake of protein and fat is necessary.
  • Limit your consumption of red meat and prefer oily fish and white meat (turkey, chicken).
  • Don’t forget minerals and vitamins! A constant supply is necessary in the preparation phase, so consume seasonal fruit and vegetables (only use supplements if strictly necessary and discuss this with your sports doctor beforehand).

The week before the marathon

As the competition approaches (1 week), the training load is reduced. As a result, the muscles accumulate glycogen and are therefore loaded with energy.

In the 3 days before a marathon, in order to maximise muscle glycogen reserves, we recommend increasing your consumption of complex carbohydrates such as bread, pasta, rice, (wholegrain) cereals and legumes. It is indeed time to replenish our body!

We must bear in mind that the estimated carbohydrate intake for each of these 3 pre-race days is between 8 and 10 grams per kg of body weight. This means that a 75 kg person can consume up to 750 g of carbohydrates per day! This sounds like a lot, but it is important to optimise energy reserves and allow the body to provide a sustained effort for 3 to 4 hours.


Below is an example of a daily menu to be consumed on one of the 3 days before a competition:

  • 200 ml of fruit juice
  • 1 yoghurt
  • 50 g of muesli
  • 5 slices of bread
  • 1 pear or 100 g grapes
  • 1 fruit compote (100 g)
  • 1 large plate of pasta (300 g), or rice (260 g, cooked)
  • Or semolina or other cereals (330 g, cooked)
  • Potato salad (1 bowl)
  • 3 slices of bread
  • 1 fruit or 1 pudding
  • 1 cup of milk + Isostar energy bar
  • 1 banana or other fruit
  • 1 large plate of rice or other
  • 1 salad
  • 2 crepes with mushrooms
  • 2 slices of bread
  • 1 yoghurt
  • 1 compote or 1 fruit

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