Biting Off More than a Cue: Incentive Salience in Prenatal and Lifetime Exposure to Junk Food

There is growing evidence that the rise in overweight and obese people is, in part, an environmentally motivated trend. This study was designed to investigate the effects of a junk food diet on cue-motivated behavior, or "incentive salience". Other measures investigated include: physiological modulation of motivation, context-reward association, hedonic "liking" reactions in the absence of motivated behavior, and anxiety. Tests were carried out in three offspring populations that were exposed to junk food, standard chow, or both prenatally through the mother and maintained on the diet throughout life. Each group showed a conditioned place preference for contexts paired with junk food, regardless of physiological state. Each group showed similar levels of reactivity toward reward-related cues during autoshaping and extinction, regardless of physiological state. Diet did, however, trend towards having an effect on hedonic "liking" reactions to concentrations of sucrose water. Animals maintained on a junk food diet displayed a blunted sensitivity to increasing concentrations of sucrose, whereas standard chow animals displayed more hedonic "liking" reactions to higher concentrations of sucrose. These observations contribute to the literature concerning effects of high fat food by investigating prenatal as well as long-term lifetime exposure to human junk food.