Treatment for Nonalcoholic Fatty Liver Disease (NAFLD) is through lifestyle modification consisting of caloric restriction and exercise, with an emphasis on weight loss. Unfortunately, the success and longevity of lifestyle changes that focus on weight loss, are poor in children. The dietary recommendation of calorie restriction alone may not be optimal in a pediatric population for multiple reasons including changes in hormonal milieu, growth velocity, and decreased bone mineral density that occur with significant weight loss. Mediterranean Diet (MD) is based on the high intake of extra virgin olive oil, vegetables, fruits, cereals, nuts and legumes; moderate intakes of fish and other meats, dairy products and red wine and low intakes of eggs and sweets. So, it provides a large amount of monounsaturated fatty acids, polyunsaturated fatty acids, vegetable proteins, fibre and antioxidants; and low amounts of sugar, cholesterol and saturated fats. It offers a lot of choice in food selection, and well tolerated, and many people can adhere to it over the long term. The investigators aimed to evaluate the effects of a MD vs. low fat diet on changes in hepatic steatosis, aminotransferases, and anthropometric measurements among obese children with NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a disease caused by abnormal lipid accumulation in the liver without alcohol intake or other organic causes. NAFLD covers a range of liver diseases ranging from simple oil infiltration to non-alcoholic steatohepatitis (NASH), fibrosis and cirrhosis. The most important risk factor in the development of NAFLD is insulin resistance due to obesity. Insulin resistance increases hepatic steatosis and accumulation of hepatic fatty acids by increasing peripheral lipolysis and the entry of fatty acids into the liver. In parallel with the increased prevalence of childhood obesity, the occurrence of NAFLD is increasing among children. The risk that the NAFLD can turn into chronic liver disease increases the importance of the disease even more when children become adults Mediterranean Diet (MD) has gained popularity in scientific literature because it is one of the healthiest diets in the world.This diet is based on the high intake of extra virgin olive oil, vegetables, fruits, cereals, nuts and legumes; moderate intakes of fish and other meats, dairy products and red wine and low intakes of eggs and sweets. So, it provides a large amount of monounsaturated fatty acids, polyunsaturated fatty acids, vegetable proteins, fibre and antioxidants; and low amounts of sugar, cholesterol and saturated fats. MD is characterized as low-carbohydrate (40% of calories) and in contrast to low-fat diets, the MD includes fat as 40% of the diet. It offers a lot of choice in food selection, and well tolerated, and many people can adhere to it over the long term. There are a limited number of studies investigating the effectiveness of the MD in NAFLD treatment in different countries. However, there are no studies in the treatment of children with NAFLD in Turkey. The primary aims to this study is to evaluate the effects of a MD vs. low fat diet on changes in hepatic steatosis, aminotransferases, and anthropometric measurements among obese children with NAFLD in Turkey. The secondary aim to this study is to evaluate the effects of the both diets in insulin resistance.

Inclusion Criteria:

• Diagnosis of NAFLD
• Body mass index z-score >85th percentile

Exclusion Criteria:

• Secondary causes of NAFLD (eg. medication induced)
• Use of weight loss medications
• Diabetes Mellitus
• Other causes of fatty liver disease (eg. Wilson disease, alpha-1 antitrypsin deficiency, auto-immune hepatitis, and viral hepatitis)

The study design was single blind and the participants did not know what diet they had taken.