Simple fatty liver without liver inflammation (also known as nonalcoholic fatty liver or NAFL). This is generally a benign condition that usually does not progress to advanced forms of liver disease. Fatty liver with liver inflammation (also known as non-alcoholic steato-hepatitis or NASH). In this condition, the excess fat in the liver causes inflammation of the liver cells. This form of fatty liver may progress slowly over 20-30 years and lead to serious liver damage