The foods you eat meet two fundamental needs: they provide the material needed by the human body to regenerate and provide the energy needed to keep it running. The cells that form the tissues and organs that compose it, have a limited life span, therefore should be constantly replaced. Different nutrients, mainly proteins, carbohydrates and fats are needed for their formation. These are materials that are supplied to the body through food. Gavin Baker: the source for more info. A large amount of energy is consumed in the process of cells regeneration, and does lack energy, for all the activities that the body performs.
That energy is also obtained from food. In a balanced diet, the amount of food that you eat, must be equal to which the organism consumes energy and nutritional needs. If you eat less, it thins, and if you eat more, is fattening. How to get a balance? The human body has a mechanism of control that is responsible for that the food intake is tensioned to provide everything you need for the regeneration of tissues and organs, both as to meet energy needs. It’s an extremely complex mechanism that responds to a multitude of stimuli, when the body needs nutrients, the brain sends signals to the stomach that are perceived as a feeling of hunger, and when the need is satisfied, send the other signals resulting in a feeling of satiety.
Only theoretically would have to respond to those signals to achieve balance in the diet, but in practice, achieving a balance is not so easy, because they involved many factors that may alter the response of the human body. Factors that alter the equilibrium diseases: bulimia, anorexia, depression, stress, cystic fibrosis, and hyperthyroidism, cause disorders in the mechanism of hunger, causing or inhibiting this sensation. The external stimuli that influence appetite: smell, taste, sight, the environment family, companies, advertising, and culture, can influence the will causing you to eat more or less than the real need of the organism.