Vulnerability to diet-induced obesity is associated with greater food priming-induced reinstatement of palatable food seeking.

We examined whether individual differences in weight gain during exposure to a "junk-food" diet were related to differences in later relapse-like behavior in a rat model. Following free access to a junk-food diet for 7 weeks, rats were trained to press a lever for palatable food pellets. Following extinction training, rats were tested for cue- and pellet priming-induced reinstatement. Results showed that rats prone to obesity while on the junk-food diet displayed greater pellet priming-, but not cue-, induced reinstatement relative to obesity-resistant rats, suggesting that obesity vulnerability is a factor determining one's chances for some types of relapse.