This study examined how the participation rates contribute to subjects' outcomes after a nutrition education (once/week) and exercise (3 times/week) intervention program for 12 weeks in 44 obese female subjects. The subjects were divided into two groups: high-participator (HP) or low-participator (LP) groups according to their participation levels based on the median visit value (30 visits out of a total of 48 visits). Daily nutrient intakes assessed by a 24-hour recall, body composition, blood lipid profiles and physical fitness were measured at baseline and after 12 weeks. After the intervention, weight, BMI, percent body fat, and the waist-hip ratio were significantly decreased in the HP group. In addition, the HP group had a greater rates of changes in weight (HP group: -6.6% and LP group: -3.1%, p < 0.01), BMI (-7.0% and -3.2%, p < 0.01), percent body fat (-7.8% and -4.2%, p < 0.05), and waist-hip ratio (-3.1% and -0.4%, p < 0.01) compared to the LP group. Energy-adjusted protein, fiber, potassium, vitamin $B_1$, vitamin $B_6$, and vitamin C were significantly increased in the HP group. The HP group showed a significant increase in HDLcholesterol and a decrease in blood pressure, total cholesterol, LDL-cholesterol, triglycerides, and atherogenic index (AI). While the muscle endurance, muscle strength, power, agility and flexibility were significantly increased in the HP group, agility and balance were improved in the LP group. In addition, dietary behavior score was significantly increased and stress score decreased in the HP group compared to the LP group. High participation rates were correlated with the improvement of the nutrient density (protein, fiber, potassium, Vitamin $B_1$, Vitamin $B_2$, Vitamin $B_6$ and folate), anthropometric parameters (body weight, BMI and percent body fat), serum lipid profiles (HDL-cholesterol, Triglyceride, and AI) and physical fitness (muscle endurance) adjusted for age, menopausal status, alcohol drinking, nutritional supplement use and baseline BMI. Our results suggest that high participation in nutrition education and exercise program was effective not only for weight reduction but also for the improvement of physical fitness in obese women.