Understanding the temporal dynamics of high-fat diets (HFD) effects on behavior and metabolism is crucial for comprehending their negative impact on organisms. This study investigated the short-term effects (15, 25, and 35 days) of HFD in Swiss mice. Our findings revealed distinct behavioral and metabolic changes throughout the treatment. After 15 days of HFD, mice exhibited impaired exploratory habituation and significant increases in visceral adipose mass, fasting glucose levels, and glucose intolerance. Extending the diet to 25 days intensified the metabolic effects, resulting in compromised acquisition of recognition memory, increased body mass gain, and elevated plasma total cholesterol and triglyceride levels. After 35 days of HFD, these effects were further intensified and accompanied by anxiogenic-like responses in the open field test. Additionally, we observed a positive correlation between metabolic changes and behavioral impairments alongside prefrontal cortex mitochondrial dysfunction. In conclusion, our study reveals the temporal dynamics of behavioral and metabolic changes induced by short-term HFD in Swiss mice, highlighting the relationship between metabolic dysfunction and behavioral impairments. These findings pave the way for future research to unravel the underlying mechanisms and develop strategies to counteract the detrimental effects of HFD on behavior and metabolism.