main objective of this study is to investigate Effects of Extra Virgin Olive Oil on Serum TNFα , Hepatic enzymes(ALT , AST) ,Lipoproteins، ،Insulin resistance، ، Anthropometric measurments and Esteatosis severity in Non – alcoholic Fatty Liver Patients and Loss Weight Diet . In this clinical trial, men and women (n=50), aged 20-60 years old who referred to clinics of mazandaran university of medical sciences in sari ,will be randomly assigned into olive oil(receiving the equivalent of 20% of total daily energy requirement from olive oil ) or control group ( receiving their usual consumption of oil )for 12 weeks.10 days before the start of intervention patients will be asked not to consume olive oil . All the patients in both groups will receive a hypo caloric diet for 90 days according to their weight, age and sex .information about anthropometric measurments (weight , waist circumference ,BMI , percent body fat ) and three - day 24 hour dietary recall will beobtained at the beginning of the study and the end of each month. physical activity , serum TNFα, liver enzymes (ALT,AST ),lipoproteins profile, fasting glucose, insulin resistance and Esteatosis severity will be determined at the baseline and after 12 weeks