Neuroanatomical Correlates of Hunger and Satiaty in Lean and Obese Individuals

Publisher Summary Eating behavior in humans is not a stereotypical behavior driven only by the need to compensate for acute changes in energy status. It is clear that emotional, cognitive, and cultural factors play a major role in the initiation and termination of an eating episode. To put it simply, a negative energy balance is sufficient but not necessary to initiate eating. However, homeostatic, hedonic, and cognitive controls of eating behavior are intimately intertwined. Their separation as discrete neurophysiological processes is, in fact, supported by theoretical principles rather than by empirical evidence. Hunger and satiety are at the crossroads of this complex interplay between metabolic and non-metabolic factors regulating human eating behavior. In fact, energy balance is continuously monitored by the brain through multiple endocrine and neural mechanisms, which include long- and short-term signals of changes in energy stores, and changes in energy currency, respectively. On this dynamic background which steers the individual toward the decision to start eating or not, or to stop eating or not, the information from the external environment, either sensorial (such as the sight, smell, or taste of food) or social (such as the availability of a scheduled “break” for lunch) may in fact act as triggering factors.