BITTERSWEET: EXPLORING THE AGE- AND SEX-DEPENDENT IMPACT OF ADOLESCENT SUGAR CONSUMPTION ON FOOD-SEEKING BEHAVIOUR

Sugar is a major contributor to excess caloric intake, and its overconsumption is strongly associated with metabolic disorders. However, whether history of sugar (over)consumption has a long-term impact on the cognitive and neurobiological processes controlling food choice and food-seeking behaviours remains poorly understood. To address this, male and female mice were given free access to standard chow and sugar-enriched diets either during adolescence (postnatal day 28-63) or at adulthood (postnatal day 70-105). Across both age groups, mice displayed a robust preference for the sugar-enriched diets. Despite this, chronic sugar overconsumption did not affect body weight. However, we observed an impairment in glucose tolerance and increased adiposity, especially in male mice, which was linked to tissue-specific metabolic dysregulation. Subsequently, mice were returned to balanced chow diet to examine the long-lasting impact of sugar exposure on flexible control of goal- or cue- driven behaviour using Pavlovian and instrumental learning paradigms. These analyses highlighted unique sex- and age-dependent consequences of sugar consumption. Notably, sugar exposure at both developmental stages increased preference for sweet foods. It also enhanced cue-driven action control, as measured by Pavlovian–instrumental transfer. In contrast, only males exposed to sugar-rich diets during adolescence exhibited deficits in goal-directed behaviour in response to outcome devaluation. Together, these findings demonstrate that even brief periods of excess sugar intake reprogram metabolism and disrupt cognitive control over food-seeking in an age- and sex-dependent manner. Ongoing work is now focused on identifying the circuit-level neuroadaptations that underlie maladaptive food preferences and elevate vulnerability to metabolic disease.