PurposeHigh-fat diet is considered as the main risk factor for the development of dyslipidemia and lipid peroxidation, which in turn results in serious health problems such as cardiovascular disease, type 2 diabetes, and some forms of cancers. Therefore, the purpose of this study was to investigate the combined effect of high-intensity interval training (HIIT) and intermittent fasting (IF) on lipid profile and peroxidation in Wistar rats under a high-fat diet.MethodsA total of 28 male Wistar rats went through a high-fat diet for 12 weeks. Then, they were randomly divided into four groups: (1) HIIT (3 days week(-1) for 6 weeks), (2) IF (3 days week(-1) for 6 weeks), (3) combined HIIT and IF (received both treatment for 6 weeks), and (4) control (CON). All groups were under a high-fat diet until the end of the study.ResultsAccording to the results, LDL levels significantly decreased in the HIIT group compared to the CON group, and in the IF and HIIT+IF groups, a non-significant increase in HDL was observed compared to the CON group. In HIIT+IF and HIIT groups, LDL/HDL ratio decreased significantly compared to the CON group (P<0.05). Moreover, in IF group, a significant decrease in TG occurred in comparison with HIIT and HIIT+IF groups. A significant increase in serum MDA levels was observed in IF and HIIT+IF groups but not in the HIIT group in comparison with the CON group.ConclusionOur results suggest that in subjects under a high-fat diet, both HIIT and IF may help to improve lipid profile, but their combination may not have any synergistic effect. Also, IF and HIIT+IF may increase lipid peroxidation in subjects under a high-fat diet.