The generation and inhibition of hedonically-driven food intake: Behavioral and neurophysiological determinants in healthy weight individuals

• We discuss the role of fronto-striatal circuitry in food reward and inhibitory control.
• Striatum response to reward cues increases with repeated highly palatable food intake.
• Increased left v. right prefrontal asymmetry may lead to striatal dysregulation.
• Greater relative striatal versus frontal activation is related to increased delay discounting.
• These changes are pronounced in those prone to obesity and may hasten with weight gain.

Given the progressive weight gain of populations in numerous countries, it can be presumed that many people eat beyond the point of nutritional repletion, in other words, for hedonic rather than homeostatic reasons. This kind of overeating is hypothesized to be due to a combination of obesogenic food environments, hyperresponsivity to food reward and deficits in inhibiting pleasure-based food intake. This paper explores the interrelationship of the latter two constructs and their neurobiological underpinnings. It also examines the potential brain changes that may take place during the course of repeated hedonic overeating and weight gain. It is hypothesized that fronto-striatal circuitry plays a primary role in this process, and that, over time, inhibitory control is eroded as reward responsiveness to highly palatable food cues increases. The unique neurobiological profile of normal weight but at-risk individuals may perpetuate continued weight gain; the neurobehavioral consequences of overeating and weight may make the permanent reversal of such weight gain infeasible.