Increased insulin levels may support the development of neural circuits involved in cognition, while chronic mild inflammation may also result in cognitive impairment. This study aimed to gain more insight into whether cognition is impacted already during adolescence in a genetic rat model for obesity and type 2 diabetes. Cognitive functioning throughout adolescence and early adulthood was investigated in Zucker Diabetic Fatty (ZDF), ZDF lean and healthy outbred Long Evans rats using operant touchscreens. Blood glucose, insulin and lipids were longitudinally analyzed. Histological analyses were performed in the liver, white adipose tissues and the prefrontal cortex. Adolescent ZDF obese rats outperformed lean rats on visual discrimination performance. During the longitudinal cognitive testing period, insulin levels sharply increased over weeks in ZDF obese rats and were significantly enhanced from 6 weeks of age onwards. Early signs of liver steatosis and enlarged adipocytes in white adipose tissue were observed in ZDF early adult obese rats. Histological analyses at early adulthood showed no group differences in the number of prefrontal cortex neurons and microglia, nor PSD95 and SIRT1 mRNA expression levels. Together, our data show that adolescent obese ZDF rats even display enhanced cognition despite their early diabetic profile.