This study is a randomized, double-blinded, placebo-controlled pilot study to evaluate whether 8 weeks of Losartan will decrease inflammatory markers among children ages 12-19 with a current diagnosis of NAFLD. Efficacy will be assessed by improvement in alanine aminotransferase (ALT) from baseline. Secondary endpoints will include aspartate aminotransferase (AST), cytokeratin 18 levels, and fasting triglyceride levels among others. Safety will be assessed by the recording of adverse events, clinical laboratory parameters, vital signs and physical examinations.