Deleterious health impacts of high dietary intake of deep-fried edible oils have been reported however, their health impacts at normal dietary levels are yet to be evaluated. This study investigated the influence of prolonged consumption of thermally oxidised long-chain saturated and unsaturated edible oils on metabolic dysregulation and inflammation. The thermally oxidised oils used in the study possess higher p-anisidine values and free fatty acid contents compared to unoxidised oils. Fourier transform infrared spectroscopy and fatty acid methyl ester analysis confirmed the presence of free fatty acids, hydroperoxides, and aldehydes, formed during thermal oxidation. The study analysed the effects of dietary intake of 5% sunflower oil, palm oil, and their thermally-oxidised forms in male Wistar rats for six months. Unoxidised and thermally oxidised palm oil-fed animals experienced metabolic syndrome with obesity-associated inflammatory changes. However, sunflower oil-fed animals exhibited increased inflammation, as evidenced by enhanced C-reactive protein, IL-6, and lipoprotein-associated phospholipase A2 activity and hepatosteatosis condition. This study indicates that prolonged consumption of thermally oxidised oil leads to the dysregulation of carbohydrate and lipid metabolism andpromotes inflammatory microenvironment in Wistar rats that may contribute to metabolic syndrome associated with obesity and hepatic steatosis.