Diet to prepare a marathon

The Marathon is the athletic event par excellence, of great demand and long distance, with a total distance of 42 km and 195 meters and today it enjoys great popularity in all the world. It is, along with other sports such as cycling or triathlon, one of those with the greatest physical wear . In addition to complying with a training session plan, it is necessary to carry out a diet that can provide you with all the energy you need to face so much effort.

Nutritional aspects to take into account in training

It is necessary to have a varied and balanced diet. This means a correct daily intake of energy and fluids, both in quality and quantity, always adapted and personalized to the characteristics of each athlete.

Training is where you can best experiment with new foods and nutritional strategies. It will be the way to check if it adapts well or not with your system. Do not start experimenting 3-4 weeks before the race as you can condition the race.

The basic nutritional needs for a runner are:


We are talking about cereals, rice, legumes, bread, pasta, potatoes … that is, the main source of energy for our muscular system during any physical resistance exercise. Without enough carbohydrates, a runner will have a hard time finding the energy to finish a race and your body will begin to burn other sources of energy, that is, proteins, that your body needs for other functions.

Hydration strategy

A good hydration strategy is essential. Make a correct hydration before, during and after training, with water or isotonic drinks if the training lasts more than 90 minutes. Being well hydrated will help the runner perform well and better tolerate fluid intake during the marathon.

The experts insist on drinking water before, during and after any sporting practice , and even more so if it is a marathon, where they can be eliminated through sweat , several liters of water.

Keep in mind that if hydration fails, dehydration occurs and a marathon requires intense effort, leading to involuntary dehydration. For this reason it is very important to keep the body hydrated before, during and after exercise.


They are essential in building muscle that has been damaged during the long kilometers of training. It is vital for recovery , since during exercise it plays a fundamental role in the structure and well-being of the muscles.

Most runners need to ingest a range of 1.2-1.8 grams of protein per kilo of body weight, and those runners training for a marathon should aim for the upper part of that range. The best sources of protein are shellfish, low-fat poultry rasa (chicken, turkey), legumes, lower-fat cuts of beef and pork, eggs, and dairy low in fat.

Muscles are made up of proteins , but these are lost during exercise, so it is important to take both before and after exercise.


Depending on the intensity of the training, the predominant energy source will vary; slow and relaxed rhythms, our body tends to use a greater amount of fat as fuel, while at fast rates , our body uses a greater amount of carbohydrates carbon (through glycogen stored in muscles, liver and circulating blood).

So, fats are the main source of fuel for moderate / long-duration, low-to-moderate intensity physical activity. However, fats are also important during high intensity exercise as is necessary to help access stored carbohydrate (glycogen).

Vitamin C and E

Vitamin C is an important vitamin for marathon runners. What interests us most is its role as an antioxidant, that is, it helps protect from the presence of free radicals and consequently reduces cellular damage from long-term exercise. Vitamin E is another antioxidant that helps protect from the presence of free radicals, which are substances that can cause cell damage as a result of physical exercise.


Helps to normalize bowel function and can help lower blood cholesterol levels. Marathon runners are normally advised to reduce the amount of fiber before running to prevent intestinal problems, although it depends on each individual case.

Aspects of the diet for competition

Based on the nutritional guidelines developed during the training phase and the experience gained, the athlete will already have an adequate dietary strategy for the race. As we have already discussed, experimenting with new foods is not recommended and strategies on race day to prevent stomach (intestinal) problems and therefore performance.

Sometimes the nerves before the race take away hours of sleep. It is recommended to avoid stimulating or alcoholic beverages as well as large or high-fat meals the afternoon / night before the race.

Breakfast should be made about 3 hours before starting the test, it should contain between 100 and 300 g of carbohydrates , and it should be made up of foods with low fat content and fiber, in addition to avoiding foods that can cause flatulence, irritants or spicy.

These are some of the most important general nutritional guidelines for running a marathon. However, a completely individualized nutritional strategy will be key to achieving your sports goal in the best conditions.

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