NAFLD is the most common cause of chronic liver disease in the western world affecting 10-30% of the general population. It is strongly associated with the metabolic syndrome caused by overweight and obesity. NAFLD is a spectrum of liver disease ranging from steatosis (hepatocytic fat accumulation occurs without hepatocellular injury), to non-alcoholic steatohepatitis (NASH) (steatosis is accompanied by inflammation and hepatocyte injury with or without fibrosis) and to cirrhosis in patients that are not consuming excessive alcohol. The prognosis of patients with simple steatosis appears benign whereas NASH often has a progressive course with increased liver-related morbidity and mortality.