Nutrition in early stages of life is one of the most influential environmental factors for the good development of organs and systems and the wellbeing of the child. Epigenetic mechanisms can explain how prenatal and postnatal nutrition affects genes expression with the subsequent risk of immune and metabolic diseases. The objective of this paper is to update the knowledge of the role the nutritional status and dietary practices of pregnant women and the child's feeding patterns over the first year of life have in the risk of future diseases.