Introduction: The general aim of this study was to evaluate and compare the effects of 12 weeks of moderate and heavy intensity exercise training and determine the optimal intensity level/rate for maximum weight loss in obese and overweight women. Materials and Methods: Forty one subjects were randomly assigned into the moderate (16 subjects with 64-76% of maximum heart rate), heavy intensity (15 subjects with 80-90% of maximum heart rate) exercise and control (10 subjects groups). Following two stages blood sampling at rest, and fasting, subjects completed appetite questionnaires. In addition, subjects exercised three times a week, one and a half hour after breakfast. Results: Results showed that calorie expenditure in the moderate intensity group was significantly higher than in the heavy intensity group. The results showed decreased weight (P=0.004) and body fat (P=0.001) in both exercise groups compared to the control group. Exercise had no effect on appetite and plasma acylated ghrelin, leptin and insulin concentrations.  Conclusion: Results showed that moderate intensity, individuals can exercise longer with there by increase the energy expenditure and controlling their appetite, fundings which can be used to design exercise programs for the prevention and treatment of obesity.