Introduction: Recent findings show that increased dietary protein intake could significantly reduce the body weight and fat mass in overweight individuals. The present study aimed to investigate the effects of one session of progressive training after two modes of whey protein supplementation on the maximal fat oxidation (MFO), Fatmax, and insulin resistance in overweight women. Methods: This clinical trial study was conducted with a pretest-posttest design on an experimental group consisting of 15 overweight women in Mashhad, Iran in 2016. At 7-10 day intervals, Fatmax, MFO, and insulin resistance index were measured in three stages of no whey protein consumption and at 30 and 75 minutes after whey protein loading during one session of progressive training until failure. Data collection tool was the ELISA kit. Data analysis was performed in SPSS version 16.0 using the analysis of variance (ANOVA), and P-value of less than 0.05 was considered significant. Results: No significant differences were observed in the MFO and Fatmax in the three stages of the study (P>0.05). However, the insulin resistance index was significant in the three stages compared to the fasting state (P<0.05), and the highest rate of insulin resistance was noted at the end of the second stage. Conclusion: According to the results, whey protein supplementation at 30 and 75 minutes before progressive training has no effect on the MFO and Fatmax, while it could increase insulin resistance.