Appetite: Psychobiological and behavioral aspects

Hunger, appetite, satiety, and energy intake (EI) are controlled by both physiological and psychological cues, many of which are learned in specific environmental contexts. Appetite is not tightly regulated but has evolved to protect humans and other mammals from energy deficits in uncertain environments and so it is relatively easy to overeat in modern affluent environments. Numerous factors influence EI including sensory perceptions, emotional state, reward-based responses to food, social and situational influences, dietary energy density, and composition. There are few clearly defined differences in determinants of appetite and EI in people with different levels of body fat, because the pathways to and from obesity are multiple and heterogeneous.