Eating for pleasure or calories

Abstract

A changing environment and lifestyle on the background of evolutionary engraved or perinatally imprinted physiological response patterns is the foremost explanation for the current obesity epidemic. However, it is not clear what the mechanisms are by which the modern environment overrides the physiological controls of appetite and homeostatic body weight regulation. Major advances have been made regarding crosstalk between metabolic signals and the cognitive/emotional brain that primarily deals with the environment. On one hand, metabolic signals such as leptin and ghrelin have previously unexpected direct effects on learning and memory, as well as liking and wanting. On the other hand, brain areas involved in reward, cognition, and executive control can override metabolic regulation by talking to the hypothalamus.

Fig. 1

Schematic diagram showing the flow of information between components of the distributed neural system controlling food intake, energy expenditure, and energy homeostasis. The broken lines with open arrows on the left indicate modulation of sensory, cognitive, and reward processes by circulating signals of fuel availability, such as leptin, ghrelin, and glucose. The full lines/open arrows indicate modulation by nutritionally relevant neural signals such as taste and visceral sensory information, as well as signals originating from the hypothalamus. Full lines/closed arrows represent neural interconnections, and dotted lines/full arrows represent conscious and subconscious behavioral, autonomic, and endocrine output/effector pathways.