In preview articles linked to the athlete diet are already deepened themes regarding the intake of macronutrients (carbohydrates, proteins and fats) and the income of water. The ideal thing is these macronutrients are put in a low glycemic index diet, that is moreover healthly and well-balanced.
The glycemic index (GI) indicates how fast your body uses sugar found in just eaten food. For example, industrial refined and depleted aliments mostly have a high GI, over 70. White bread even reaches the maximun value on the GI measuring scale, that is 100. Food with a low GI staying under 50; that with a GI between 50 and 70 have a medium glycemic index; finally food with upper values than 70 have a high glycemic index. The GI is a universal value and does not change depending on the amount. However, for determining the value of a complete meal it is useful to consider the glycemic load (GL), that is the result of the glycemic impact of the food sum found in the plate, also depending on their cooking and the presence of fats, fibers and amides. The glycemin index can be useful as a starting point to evaluate food individually consumed, but to understand how much can be the impact of the food combination of a only meal on glycemia (also taking account its cooking way) the best reference is the GL, which we can calculate by multiplying GI for the amount of carbohydrates contained within food and dividing by 100.
In practice, factors which can help to reduce the glycemic index are a lower refining (you must choose cereals with wholegrains), the presence of fats and proteins, the presence of febers, the cooking time decrease (for pasta and rice), the freezing (the food firstly cooked, then freezed and later heated has a lower GI), finally the cooking way of the legumes (it is necessary to leave them to soak for about 8-12 hours, to throw away the soaking water and then to cook them in a pot at over low heat for the required time).
The glycemic index impact of the diet on the body composition is really remarkable. This happens because glucose (the simple sugar derived by carbohydrates we assume) is assorbed at intestinal level and passes into the blood; then it is picked up by the liver, muscles and adipose tissue (body fat). However, the muscle and the liver have such a "biochemical little gate" which controls the glucose entrance, so they acquire just what they need. The adipose tessue, indeed, does not have this advantage, consequently it achieve all the available glucose without restriction. Here you are the reason why more peaks of glycemia there are, more we tend to gain weight.
The aim of the athlete in particular is to increase the lean mass, mostly determined by muscle mass, and to reduce fat mass. A low glycemic index diet, for just mentioned reasons, surely will help the athlete to achieve this aim. The only moment in which he can go wild is just after an intense sport activity, because during the hour after the workout there is the highest muscle capacity to gain blood glucose.
An other important consequence to repeated glucose peaks to which everybody, especially the athlete, must pay attention, existes: silent inflammation, which caused malaise, swelling, fatigue, etc. This inflammation linked to food can have a direct impact not only on athletes physique perfomance, but also on their daily life. When the muscle is inflamed, its fibers are subject to a continuous oxidative stress which simplifies possible damage and avoid to the muscle to correctly work. When the level of inflammatory cytokines increase, extracellular water grows and even so much trained muscles promote muscular injuries and articular overload.
Anyway, an dietary habits with high glycemic peak, beyond to have an unpleasant impact on health, affecting the outbreak of many pathologies, also acts on body composition and sport performance.
By Maria Parisi
Translated by Giorgia Melis