Malnutrition comprises both undernutrition and overweight/obesity, and it is suffered by about a quarter of the worldwide population. The long-term consequences of undernutrition on body growth and brain development have been largely studied. Although less studied, recent research reports that also overweight can have consequences on brain development. Most interestingly, changes in lifestyle and diet have resulted in a new phenomenon, known as the double burden of malnutrition (DBM). Among DBM phenomena, children can suffer from undernutrition in the earlier years of development, and experience overweight and even obesity later in childhood. The consequences of these alterations in body mass and metabolism have not been extensively analyzed, and their effect on brain development is unknown.
Here, we performed a meta-analysis, searching for the current knowledge of the consequences of undernutrition and obesity on brain development, and their effects on brain function, especially on animal behavior. We identified a variety of protocols to model both undernutrition and obesity in rodents and analyzed the strengths and weaknesses of each model. Although no model completely recapitulates de particularities of human malnutrition, we conclude that animal studies can shed light on unexpected consequences of early alimentary behavior on brain health