Objective: The main objective of this study is to assess the effects of Vitamin D spplementation on changes in the secrtion of some hormones such as DHEA and Insulin and antioxidant enzyme to reduce oxidative stress in the body in an overweight and obese adult undergoing of low calloeie diet. Design of study: Randomized, double blind, placebo controlled, single center and phase 2-3 trial. Setting and codduct: 70 overweight or obese volunteer age between 20 -50 years old and BMI between 25 – 40 kg/m2 will be recruited.We have 2 groups: 35 persons that will receive vitamin D , 35 persons that will receive placebo of vitamin D . The duration of intervention is 8 weeks. Participants including major eligibility criteria: Overweight and obese adults 20 -50 years old with BMI between 20 - 40 Kg/m2, having a weight loss diet for 3 months before the study initiation and consumption of Vitamin D, use of tanning bed and antioxidant supplemention during and 3 months before study and Vitamin D >30 ng/dl will be excluded participants from study. Intervention: We will start intervention with a bolus dose (50000 IU vit D) in first week along with weight reduction diet and will be followed by daily doses(2000 IU vit D/ day) after a week in intervention group, and control group will receive placebo of vitamin D (edible paraffin) with weight reduction diet for 2 months. Main outcome measures: DHEA, Insulin, apo B100, apo A1, PON 1, FFA will measure with ELIZA. With BIA method we will measure the fat percent of the body and Viscan devices will be used for observation of visceral adipose tissue changes. (after and before of study).