If we stop taking food, we could neither live nor grow. It is determined what nutrients our bodies need and how much of these substances should be to preserve healthy state of organism. In other words, it is not enough just to eat, but we must take a sufficient quantity of each type of nutrients.
Foods rich in protein ( milk, eggs, cheese, meat and fish ) contain large amounts of these substances that body require to build new cells.
Carbohydrates ( potatoes, flour, rice, cakes ) contain a large amount of starch or sugar, which are important for the body because they held the heat and give it an energy. Almost all foods contain a certain amount of fat, and they give the body the most of energy it needs.
However, the body needs not only proteins, carbon hydrates and fats, but also substances called minerals. There are eighteen necessary minerals. Calcium and phosphorus allow growth and maintenance of bones and teeth. Iron promotes proper cell growth. Copper allows the body to grow and produces hemoglobin. Iodine also helps the body work, etc.
Let us mention that the water can be considered as food, it serves the body in several ways. From all this, you can see that eating is not only satisfying hunger and desire for a good meal. A good, balanced diet is essential for maintaining a healthy body.
Thus, proteins, carbon hydrates, fats and minerals are equally necessary for the activities and growth of the organism. Is that all? It is not. Organism also needs vitamins and control to many life processes.