Non-alcoholic fatty liver disease (NAFLD) is a disease spectrum that encompasses excessive liver deposition of fat (NAFL), non-alcoholic steatohepatitis (NASH), and NASH cirrhosis. NAFLD is regarded as the hepatic manifestation of metabolic syndrome and is currently the most common etiology for chronic liver disease worldwide, affecting 25% of the adult population globally. It is estimated that cirrhosis and liver-related death occur in 20% and 12%, respectively, over a 10-year period in patients with NAFLD. The incidence of decompensated cirrhosis and hepatocellular carcinoma (HCC) due to NAFLD are increasing with time. In United States, the number of patient listing for liver transplantation (LT) due to NAFLD has surpassed that of from chronic viral hepatitis and is currently the second leading cause for LT waitlist overall. Locally, the prevalence of NAFLD is estimated to be 42% according to a health census in healthy blood donors in Hong Kong, and up to 13.5% healthy subjects will develop new onset NAFLD in 3-5 years of follow-up. Clearly, NAFLD is a chronic liver disease with alarmingly high prevalence that warrants attention. Despite the high prevalence and potential to develop serious liver-related morbidity, there are currently no approved drugs for patients with NAFLD. To achieve resolution of steatohepatitis and improvement of liver fibrosis, weight loss appears to be the only effective means. This study is aimed to evaluate the effectiveness of a self-developed smartphone app for achieving weight loss in Chinese adults with non-alcoholic fatty-liver disease (NAFLD) at 12 months. Endorsed by the WHO, mobile technology is being increasingly used to promote health. There is a lack of research on the use of mobile technology for promoting weight loss in Chinese NAFLD patients.