This study was carried out to investigate the effect of body weight reduction of patty containing glucomannan in high fat diet-induced obese rats. Male Spraque-Dawley rats were randomly assigned to control and high fat diets groups for 4 weeks. After 4 weeks, the control and high fat diet groups were rearranged into 5 groups by different levels of patty containing glucomannan (60%). After 5 weeks, serum and whole blood levels were analyzed. Obesity index was significantly lower in the group fed patty containing glucomannan than that of high fat diet groups. The status of white blood cells in hematological examination was significantly higher in rats fed high fat diet and not significantly different from those fed patty. Serum albumin levels were not significantly different, while serum glucose levels were significantly different among groups. Serum Triglyceride and total cholesterol levels were the highest in rats fed high fat diets, while the lowest in rats fed patty containing glucomannan.