The calories consumed in running

C = P x d

In addition, the individual variable of running efficiency should also be considered, which can account for more or less 20%.

Far more interesting is the consideration on the "fuel" used by the athlete.

It is believed that the athlete normally uses carbohydrates, and that the use of fat is involved only at low speeds (for example, in the marathon it is estimated that 20% of fat is used).

In fact, it has long been proven that even proteins (find out more about proteins) are used for energy purposes when glycogen stores are low.

The fuel used depends on three factors:

1. The speed at which you run
2. The degree of training
3. The ability to run in conditions of glycogen depletion

The third point tells us that the more the athlete is used to running with low carbohydrate stocks, the more his ability to burn fat and protein increases. This happens in those who train every day (athlete A) and often have to do it without having completely recovered from the previous training.

Those who train three times a week (athlete B) will perform the training having fully recovered and their physique will continue to use carbohydrates.

In the case of a slow bottom of 20 km it can be assumed that for athlete A the mixture is 60% carbohydrates, 30% fats and 10% proteins, while for athlete B 80% carbohydrates, 15% fats and at most one 5% protein.

Apart from the percentages, it should be noted that this new vision is capable of explaining why type B athletes usually have poor recovery capacity. If their glycogen stores are not at their peak, their performance drops dramatically; while for type A athletes the decrease is less noticeable.