Introduction

Non-alcoholic fatty liver disease (NAFLD) is now considered to be the most common cause of liver disease in both adults and children in the USA because of its strong association with the epidemic rates of obesity across all age groups. Originally considered predominantly to be a disease of developed countries with affluent and sedentary lifestyles, NAFLD has emerged in the last decade as a significant cause of liver disease worldwide, even in developing economies [1]. Increasing industrialization and commercial globalization in Asia, South America, and the Middle East have led to significant population shifts toward more western dietary habits and reduced energy expenditure, which, in turn, have increased the prevalence of overweight and obesity, and led to the identification of NAFLD as a common cause of liver disease [2].

While diverse conditions can lead to abnormal hepatic steatosis, defined as steatosis in >5% of hepatocytes, NAFLD is predominantly associated with excess adiposity, in particular central adiposity, and occurs in the absence of significant alcohol intake. It can be found in lean individuals but typically they too have significant visceral adiposity or severe insulin resistance syndromes, such as lipodystrophy [3].