The metabolic processes are divided into Catabolism and Anabolism, which depend on each other.
Catabolism is the set of metabolic processes in which complex molecules are decomposed to obtain simpler ones; in this way, energy is released in the form of ATP (Adenosine Triphosphate) and then used to perform all internal and external activities of our body.
Anabolism is the set of metabolic processes for the production of complex molecules from simpler ones. These processes are fundamental for the creation of new cells and the maintenance of all tissues, and use the energy released in Catabolism and supplied by the ATP.
The biochemical reactions of these metabolic processes are catalyzed by enzymes and organized into metabolic pathways, which are classified into catabolic pathways, anabolic pathways and amphibolic pathways (both catabolic and anabolic).
When Anabolism exceeds the activity of Catabolism, the body grows or gains weight; if Catabolism exceeds Anabolism, as it happens in periods of illness, the body loses weight. When both processes are balanced, the organism is said to be in dynamic equilibrium.
Cells and tissues die continuously, but Metabolism provides all the biochemical ingredients needed to replenish and create new cells.
Food supplies many substances that are essential for the construction, maintenance and repair of body tissues, and for the functioning of our body. These nutrients come mainly from carbohydrates, lipids (fats) and proteins. In addition, we cannot forget about water, which is vital for our body.