https://www.farm.ucl.ac.be/Full-texts-FARM/Roberfroid-2000-3.pdf

To understand functional food it is first necessary to understand how the science of nutrition itself has changed. Nutrition has progressed from the prevention of dietary deficiencies and the establishment of the concept of balanced diet to the promotion of a state of well-being and health and the reduction of the risk of disease, as well as the development of the concept of optimum (optimized) nutrition