This study aimed to evaluate the effect of weight loss diets in experimental obesity. Forty –five male albino rats, 6-8 weeks old, were randomly assigned into four groups: Group 1 (Control normal group)   : Comprised 10 rats, provided only with regular diet and plenty of fresh. Group 2 ( Control obese group with 75 calories diet) : Included 10 rats ,was received a high fat diet for 4 weeks period  then each rat was fed daily with 75 calories diet for 8weeks .Group 3 (Obese group with 60 calories diet): Included 10 rats ,was received a high fat diet for 4 weeks period then each rat was fed daily with 80% calories of the Control obese diet for 8weeks (60 calories diet) .Group 4 (Obese group with 45 calories diet) : Included 10 rats ,was received a high fat diet for 4 weeks period then each rat was fed daily with 60% calories of the Control obese diet for 8weeks (45 calories diet).Blood samples were collected after 8 and 12weeks of supplementation for biochemical analysis. As compared to the control normal group, control obese group exhibited a significant decrease in serum high density lipoprotein-cholesterol (HDL-c), transferrin and total iron bending capacity(TIBC), along with increase in aspartate aminotransferase (AST) activity, total protein, albumin, urea, creatinine, total cholesterol ,plasma triacylglycerol, very low density lipoprotein-cholesterol (VLDL-c), low density lipoprotein-cholesterol (LDL-c),sodium ,calcium , iron concentration and Plasma ferritin concentration. Meanwhile ,  the obese group  provided with 60 calories diet exhibited a significant decrease in AST activity, total protein, albumin , urea, creatinine,  total cholesterol , triacylglycerol ,VLDL-c, LDL-c, sodium ,calcium , iron concentration and ferritin along with increase in HDL-c, transferrin and TIBC when compared with obese group. However, the obese group provided with 45 calories diet, exhibited a significant decrease in total protein concentration, albumin, T. cholesterol, triacylglycerol, VLDL-c, LDL-c, sodium, calcium, iron concentration and ferritin along with increase in AST activity, urea, creatinine, HDL, transferrin and TIBC, when compared with obese group. In conclusion, Low calorie diet reduces calorie intake without incurring malnutrition or a reduction in essential nutrients compared with very low-calorie diet.