Adolescent and adult age differences in palatable food learning and consumption

Adolescents are sensitive to food rewards and are at a risk of developing binge and other eating disorders. Adolescence is also a period of rapid learning. It is known that food memories can motivate appetite and food seeking without hunger, and food cues can induce relapse of extinguished behaviors. Yet, little is known about how adolescents learn about palatable food cues under hunger and satiety, and if males and females differ. The current study investigated Pavlovian conditioning, extinction, and context-induced renewal of cue-food associations, as well as palatable food consumption, in hungry and sated adolescent and adult male and female rats. Adolescents were less responsive to satiety during cue-food learning and had greater persistence of cue-specific memory. Sated adolescents acquired conditioned responses (foodcup approach and latency) faster than sated adults. Adolescents also had slower extinction and more robust renewal of conditioned responses to the food cue after extinction. In both adults and adolescents, hunger enhanced acquisition and amplified overall responding during extinction but did not impact renewal. Sated rats had similarly robust renewal of conditioned responses following extinction as hungry. During consumption tests, there were distinct age and hunger state differences. Adults consumed more of the palatable food compared to neutral-tasting chow regardless of satiety state. Sated adolescents also preferred palatable food and consumed more than sated adults. In contrast, hungry adolescents showed a balanced intake of both foods, suggesting they may prioritize physiological needs over hedonic rewards. Females consumed more palatable food than males, regardless of age or hunger state. These findings highlight developmental differences in reward learning and memory, with implications for understanding vulnerabilities to disordered eating during adolescence.