The consumption of diets enriched in fats has been implicated in the impairment of neuronal plasticity and cognitive function. These dietary patterns have been closely associated with disruptions in glutamatergic signaling within the hippocampus, a crucial brain region for learning and memory processes. In the present study, we investigated the enduring effects of lifelong consumption of diets enriched in saturated (SOLF) and unsaturated (UOLF) fats on i) spatial learning and memory, ii) hippocampal synaptic transmission and plasticity, and iii) gene expression of glutamatergic and hormone receptors in the hippocampus and prefrontal cortex of aged male and female mice. Our findings reveal sex specific responses and distinctive behavioral and molecular outcomes associated with each dietary regimen, with SOLF demonstrating a more deleterious impact in males than in females. These results underscore the significance of considering sex specific factors when assessing the prolonged effects of high fat diets on cognitive, behavioral, and molecular aspects. Insights gleaned from this study contribute to a better understanding of the ramifications of obesity and lifelong consumption of fatty foods, shedding light on the intricate interplay between diet, sex, and health throughout the lifespan.