Walking and marathon are two disciplines made fascinating by a mix of fatigue and emotions difficult to understand by those who, at least once in their life, have not had the opportunity to practice them.
How should the walker and the marathoner be fed?
The daily diet should focus, first of all, on the consumption of a wide variety of foods. In fact, we know that there are no complete foods and that each of them provides different percentages of individual nutrients.
The Mediterranean diet is the reference model for any endurance athlete. Although this eating style gives a lot of importance to carbohydrates, we must not forget the fundamental role of fats and proteins, which must always and in any case be taken in the right proportions. Obviously it is important to obtain these nutrients from the best food sources, such as olive and seed oil, for fats, and white meat, legumes and fish, for proteins.
The rule of 5 can be particularly useful for walkers and marathon runners:
do not let more than five hours pass between one meal and the next;
eat at least five meals a day (breakfast, lunch, dinner + two snacks)
Carbohydrates and maltodextrin supplements
Carbohydrates are the main energy substrate of our body. For this reason, they should provide around 50-60% of daily calories on their own.
Not all carbohydrates are the same, some are rapidly digested and absorbed (with a high glycemic index); others are assimilated slowly, ensuring a moderate but constant flow of energy over time (low glycemic index).
Each gram of carbohydrates provides an average of 4 calories. In the liver and muscles of the athlete there are, in the form of glycogen, from 250 to 450 grams of glucose (in relation to the state of nutrition, training and body size). These deposits guarantee a reserve of 1000-1800 calories, sufficient to travel from 20 to 35 km. Once this threshold is exceeded, especially if the body is not well trained to derive energy from fats and save glycogen, there is inexorably against a decline in performance, which for some translates into a real and its own crisis.
Carbohydrate food supplements are intended to provide energy in the short, medium and long period of time. These products can be used:
before exertion, to increase muscle and liver glycogen stores in the days preceding the competition;
during the effort, to replenish the oxidized glucose and prevent the total exhaustion of glycogen reserves;
after exertion, to accelerate recovery by restoring carbohydrate stocks.
Proteins and amino acids
The requirements for amino acids and proteins are also significantly higher. Runners and walkers find themselves having to face the loss, albeit modest, of those amino acids used for energy purposes during training and competitions. Physical effort also increases protein turnover, that is the replacement of proteins, first of all those that are contractile, worn out and no longer efficient.
The correct distribution of food in the five daily meals guarantees a constant supply of proteins, thus providing multiple advantages:
if too many proteins are taken at once (over 30-35 g), the effectiveness of the absorption processes decreases;
the stimulus to protein synthesis remains high for a few tens of hours; a "constant" protein supply during this period guarantees the maximum availability of amino acids for cell regeneration processes.
Protein supplements?
The daily protein requirement of those who regularly practice cross-country disciplines, such as walking and marathon, is between 1.4 and 2 grams of protein per kg of body weight. If the diet includes a small protein source at each meal (dried fruit, legumes, meat, fish, cheese or eggs), no specific supplementation is normally required.
On the other hand, integration with single amino acids, such as branched amino acids (BCAA) or glutamine, deserves a separate discussion. It is precisely the products containing these nutrients that represent the fulcrum of food supplementation for endurance athletes.
During intense and prolonged physical activity, the body mainly uses these amino acids as a source of glucose and additional or "emergency" energy. Glutamine is also important for strengthening the immune system and increasing resistance to infections, while an adequate supply of BCAAs counteracts the perception of fatigue towards the end of prolonged activities.
As it is logical to think, if the consumption of amino acids exceeds the dietary intake, the muscle weakens and gradually loses its efficiency. Precisely for this reason, despite being contained in meat or fish to an extent of about 2%, supplementation of BCAAs can help improve sports performance or at least accelerate recovery, removing the risk of overtraining (especially when associated with glutamine).
The recruitment schemes normally proposed are the following:
Branched chain amino acids 4-6 g / day
daily intake: immediately after the activity - anabolic phase -
or at the end of the effort and before going to sleep
or 2-3 grams 30-60 minutes before physical activity + 2-3 grams at its conclusion.
In long trials, branched chain amino acids can also be taken during competition (1 gram per hour)Glutamine: 1-3 grams
60 minutes before the start of the effort together with carbohydrates, as in addition to being better absorbed in conditions of high blood sugar, it satisfies the increased metabolic demands during physical exercise.
Immediately after training or in any case within thirty minutes from the end of the exercise. In this case the integration is recommended together with abundant liquids and branched amino acids, in order to favor the recovery and the cellular anabolic processes.
On an empty stomach, possibly before bedtime, to stimulate the secretion of gh.
Second part "
