Diet specifically to the field of study that "the process, by absorbing creatures, metabolism, and the use and disposal of food." This science is still young and dealing with the terribly complicated.
It must be remembered that the systematic identification of basic foodstuffs and roles do not start until the early twentieth century. Since the 1950s, and dietetics suffer increasingly from chronic diseases, degenerative or obesity (diabetes, heart disease and vascular, cancer, obesity, allergies) that have a genetic reasons, but also for the external (diet and lifestyle, pollution, etc.).
Since then emerged the concept of a balanced diet has been refined potential damage of the modern diet, industrial techniques highlighted. Recently we began to better understand the role and synergies of vitamins, minerals and trace elements, antioxidants (flavonoids, carotenoids) and amino acids.