Epidemiology of Malnutrition (Over and Under Nutrition)

Nutrition is closely connected to population growth and constitutes a fundamental area for the health and development of societies. Since its appearance on Earth, the number of human beings has steadily increased, and in 2022, the world population reached 8 billion people. However, despite the great scientific and technological advancements that have enabled this growth to happen, humanity is currently facing a twofold phenomenon, namely, “the double burden of malnutrition,” in which both undernutrition and overnutrition are simultaneously present. Impairments in nutrient balance can be due to a deficiency or excessive consumption of food groups, individual foods and/or single nutrients. Therefore, the present chapter takes into consideration the different aspects of malnutrition with the aim of providing a broad overview of the current situation of the main diseases related to malnutrition from an epidemiological perspective. The data reported helps to understand that the current situation is far from being resolved. On the one hand, undernutrition, when it has not worsened, has brought about few improvements in the last decade and, on the other, overnutrition is progressively and incessantly increasing.