Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in affluent countries. It may progress to cirrhosis and liver cancer. At present, there is no approved drug for NAFLD. Although healthy diet and exercise is often recommended, there is little supportive evidence. Therefore, the investigators plan to conduct a randomized controlled trial comparing a low glycemic index dietary intervention program and simple lifestyle advice in NAFLD patients. The primary endpoint is resolution of NAFLD. Non-invasive tests will be used to assess the study subjects. Proton-magnetic resonance spectroscopy is used to quantify hepatic triglyceride content, and transient elastography is used to quantify liver fibrosis.

Inclusion Criteria:

• Age 18 to 70 years
• Fatty liver by proton-magnetic resonance spectroscopy, defined as hepatic triglyceride content 5% or above
• Serum alanine aminotransferase (ALT) above 30 U/L in men and 19 U/L in women
• Informed written consent obtained

Exclusion Criteria:

• Positive hepatitis B surface antigen, anti-hepatitis C virus antibody, or anti-nuclear antibody titer above 1/160
• Alcohol consumption above 30 g per week in men or 20 g per week in women
• Alanine aminotransferase (ALT) above 10 times the upper limit of normal
• Liver decompensation, as evidenced by bilirubin above 50 µmol/l, platelet count below 100 × 10e9/l, prothrombin time above 1.3 times the upper limit of normal, albumin below 35 g/l, presence of ascites or varices
• Evidence of hepatocellular carcinoma
• Terminal illness or cancer, unless in complete remission for more than 5 years