The body needs energy to function, since it is consuming it 24 hours a day. Is Energy it is provided solely by food. But, if it is higher than your best before date, you start to get fat.
A multitude of chemical reactions take place within the millions of cells that make up our organism. These chemical reactions transform the elements into energy values of (proteins, carbohydrates, and lipids) contained in different foods. This energy is consumed or stored.
For this reason, proteins, carbohydrates y lipids must be present in certain proportions in the eating, in order to respond to your energy wear, and that they do not accumulate in organism. Storage is the extra kilos.
No food contains these foods values of as a whole, and in the right proportions. Hence the need to eat everything, and vary the diet as much as possible. This is the basic rule of a eating balanced and of a stable weight. At the same time, the necessary rates of Vitamins and mineral salts are guaranteed.
Each element nutritional plays its own well-defined role. Proteins are constantly renewed in the organism. When they have been used, they degrade and provide energy. The right proportion: 15% of the daily calories.
The carbohydrates They are essential because they provide the necessary energy for the whole day. The right proportion: 50 to 55% of the calories The lipids they also provide Energy, but they are rarely used immediately. It tends to accumulate in the tissue adipose and it is only spent during a significant physical effort. The right proportion: 30 to 35% of calories.
More information - How to get a balanced diet