Elucidation of the metabolic pathway due to 50% dietary restriction carried out in this study. Seventy male and female wealning rats, weighed $43{pm}2g$ were divided into seven groups, 10 rats each. Twenty rats, ten males and ten females were sacrificed every three weeks after 50% dietary restriction for whole length of the experiment, nine weeks. Pair-feeding was employed in this study. According to the increment of the dietary restricted period, the body and organ weights were decreased. Especially liver and spleen were mostly shrinked in their weights, and brain was the most stable organ in account of dietary restricted effect. In comparison nitrogen retention between restricted and unrestricted groups, the former showed lower than the later but tubulated into the rate of Nitrogen retention per gram of body weight, reverse was true in this respect. In regardness of the experimental organs, spleen revealed the most fast change and the brain the most slow change their content of RNA and DNA in account of the 30% dietary restriction. Hematological investigation did not show any anemic conditions in both restricted and unrestricted groups. Also serum albumin contents A/G ratio, did not effect due to 50% dietary restrictions.