Nutrition science dealing with sport has made progress in the latest few years and its most important aim is giving the athlete the possibility to improve his performance more and more. In fact, it is only through a rational use of meals that stimulus coming from nutrition can help physical efficiency to grow, avoiding running out of energetic reserves and optimising recovery. Another important aim is reducing accidents and let the athlete training in a more intensive way. Therefore, every athlete will be able to get a higher performance and better results.

The Zone diet is the result of studies made by Barry Sears, an American bio-chemist. The purpose of this diet aims to influence the hormonal condition through a correct mix of macronutrients, that are carbohydrates, proteins and fat. The diet represents a "revolutionary stimulus" for the nutrition science.

By "Zone diet" we mean a real physiological condition of our body, where hormones, which can be controlled through nutrition, are well balanced in order to create an optimal wellness condition. Consequently, this condition can lead both the professional sportsman and the amateur to get the maximum from his body.

This kind of nutrition does not represent a strategy to lose weight only, as someone thinks, but also a new system, through which we can actively control our hormonal balance and, particularly, the level of some hormones called "eycosanoids". These hormones, taken from the essential long-chained fat acids, are considered as the most powerful hormones in our organism, since they can influence synthesis of every other hormone and many more other physiological aspects.

Eycosanoids are a kind of hormones which act on the same cell they have been created by. They are consequently called "ghost hormones" too, because they act in less than a second.

Eycosanoids have been divided into "good" and "bad eycosanoids" and they have opposite physiological effects.

Good eycosanoids:
increase blood fluidity
improve immunity system and cerebral functioning
reduce pain

Bad eycosanoids:
worsen blood fluidity, immunity system and cerebral functioning
increase pain.

We can control eycosanoids through omega 3 fat acids (mostly contained in fish oil) and by keeping insulin and glucagone under control. These ones, both produced by pancreas, are directly influenced by our nutrition. Insulin is created by the increase of glycaemia (concentration of glucose in blood) and it represents the key factor. As a matter of fact, through the activity of a particular enzyme called delta 5 desaturasi, glycaemia stimulates the production of arachidonic acid, the responsible for the production of bad eycosanoids. Glucagone, on the contrary, put into blood circulation by the proteins, goes against the rise of insulin, it stops the production of arachidonic acid and it contributes to the production of good eycosanoids. Scientific basis of the Zone Diet are to be found there.

In order to obtain all the positive aspects of the Zone Diet, one should:

• Balance carbohydrates, proteins and fat in every meal (breakfast, lunch, dinner and snacks): 40% of calories must come from carbohyrates, 30% from proteins and 30% from fat.
• Never stay without eating for more than five hours between two meals.
• Divide food into three main meals and two snacks (sometimes it is important to get a snack even at night, before to sleep).
• Do not exceed with quantities in every meal.
• Do not assume too many simple carbohydrates, such as sugar, sweets and sodas.
• Eat more fruit and vegetables (source of carbohydrates which stimulate secretion of insulin).
• Drink much water (at least 2 litres a-day totally).
• Take at least 2 grams a day of omega 3, contained in fish oil, obtained through molecular distillation (a process that eliminates polluting elements of the sea).
• Nutritional and food sources have to be selected according to a simple criterion. We must assume food that does not create too much insulin and which does not contain too much saturated fat.
  That is why we have to choose our nutritional sources:

PROTEINS

Recommended: chicken, turkey, rabbit, fish, lean red meat, egg-white, lean dairy products.
To be avoided: fatty meat, fatty dairy products, packed food, offal and giblets.

CARBOHYDRATES 

Not all carbohydrates are recommendable; increasing of glycaemia, in fact, depends on the different types one takes: carbohydrates with a high glycaemic level (such as sweets, sodas, potatoes, honey, bananas, sugar) stimulate glycaemia levels and should be limited. On the contrary those ones with a low glycaemic level (such as fruit, vegetables and wholemeal food) are particularly suggested.
Recommendable: vegetables and fruit, except carrots, potatoes, bananas
To be eaten moderately: pasta, rice, bread
To be avoided: croissants, packed food, sweet drinks

FAT

Recommended: extra-virgin olive oil, fish-oil, dried fruit
To be avoided: butter, yolk.