We all know that proper nutrition guarantees a good performance, but there are various DIFFERENCES BETWEEN SPORTS AND SPORTS.
An optimal diet should provide the necessary components and cover the energy demand; this includes:
- the need to repair the tissues
- provide for the resurfacing of some macromolecules
- allow growth
There are big differences between sports activities in terms of energy expenditure. For example, a two-day climb on Mont Blanc takes about 9,000 kcal, an alpine stop on the Tour of France can take up to 6,000 kcal in one day, a triathlon race about 5000 kcal. When energy consumption is so high it is objectively difficult for the subject to be able to balance energy expenditure with food intake. However, the rule of the balance must be respected even if this is achieved in a longer time. In the presence of calcium deficiency, the subject loses weight, at the expense of the fat mass, but also loses muscle protein structure.
In resistance sports the main fuel is fat*. Of these, there is normally a great availability in the body, and vice versa, sugars reserves are relatively limited. The latter are present in the muscles and liver as a polymer called glycogen (about 200 gr in the muscles and the same in the liver) and as free glucose in the blood (at a concentration of about 0.1 gr/dl). Even during a resistance test (marathon, mountain trip), there is always a certain use of sugars, in the face of a preferential use of fats. In addition, despite the fact that the muscles have a certain amount of substrate, they also have to use substrate that come from blood.
For example, for an exercise that lasts for 3 hours, about 86% of oxygen consumption is responsible for oxidizing fat and plasma glucose (50% and 36% respectively), only 14% is used to oxidize the substrate already present in the muscle. The common case is that of sugar deficiency that manifests itself with the hypoglycemia. For this reason, it’s important to reintegrate sugar reserves. Hypoglycemia involves typical symptoms: extreme fatigue, nausea, headache. This condition must be avoided by introducing sugars*** to compensate for losses. Often, in addition to the depletion of sugars, there is the problem of dehydration. In this case it’s useful to take every 20 minutes about 100-120 ml of a drink containing 3-5% glucose concentration and salts to compensate for those lost with sweat. When the organism approaches the hypoglycemic condition, it performs a particular metabolic pathway in the liver, which, starting from the branched alanine amino acid, allows glucose synthesis.
Sports of Strength
Now let’s see the case of subjects who dedicate themselves to activities predominantly of strength. In this case the main problem is related to the fact that training of this type induces muscle hypertrophy and it’s therefore necessary to provide the body with a protein intake that allows the deposition of a new protein matrix.
Proteins** come from meat, cheese, milk, cereals (durum wheat) and some legumes (beans, peas, lentils, chickpeas). The average need in terms of protein intake is 1gr per kg of body weight per day.
Weightlifters, bodybuilders, gymnasts tend to even take 3 gr/kg per day. Physiology research on this topic doesn’t confirm this need.
Surprisingly, the need for protein intake is slightly higher in athletes who rely on resistance tests, which cover 20-30 km per day in training.