Obesity (OB) and eating disorders (ED) are two complex weight/eating conditions that share phenotypic traits, including psychopathological variables, specific environmental risk factors and biological vulnerabilities. Both OB and ED are associated with maladaptive eating styles that may be relevant to their development and maintenance. In abnormal/excessive eating behavior, a complex interplay among physiological, sensorial, psychological, social and genetic factors influence appetite, meal timing, and the quantity of food intake and food preferences. Neurobiological functioning has also been found to be altered in extreme weight conditions, namely with regards to reward processing, emotion regulation and decision making. In this presentation we will discuss the relevance of such components as well their interaction using findings from cross-sectional and longitudinal studies conducted in extreme eating/weight conditions, when compared with healthy controls. The development of innovative treatments considering neurobiological factors will also be covered.