The world's population is increasingly overweight and obese. According to the World Health Organization (WHO) as of 2010, 43 million children under the age of five were overweight. Once considered to be limited to developed countries, overweight and obese children are now found in low- and middle-income countries, though most commonly in urban areas. Furthermore the WHO now cites the conditions of overweight and obesity as being associated with more deaths around the globe than those associated with being underweight. With this increased prevalence of overweight and obese children has come a host of other medical problems including nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). This review will focus on NAFLD and NASH, their definitions, epidemiology, diagnosis and treatment. The authors will also discuss NAFLD in the Indian subcontinent, and the future of NAFLD and NASH.