NAFLD/MASH (Nonalcoholic Fatty Liver Disease / Metabolic Dysfunction-associated Steatohepatitis) is a range of liver conditions affecting people who drink little to no alcohol.

NAFLD

As reported by the National Institutes of Health, Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat is stored in the liver. This buildup of fat is not caused by heavy alcohol use. When heavy alcohol use causes fat to build up in the liver it is called alcoholic liver disease.

Two types of NAFLD are simple fatty liver and Metabolic Dysfunction-associated Steatohepatitis (MASH). Simple fatty liver and MASH are two separate conditions. People typically develop one type of NAFLD or the other, although sometimes people with one form are later diagnosed with the other form of NAFLD.

Simple fatty liver

Simple fatty liver, also called nonalcoholic fatty liver (NAFL), is a form of NAFLD in which you have fat in your liver but little or no inflammation or liver cell damage. Simple fatty liver typically does not progress to cause liver damage or complications.

MASH

MASH is a form of NAFLD in which you have hepatitis—inflammation of the liver—and liver cell damage, in addition to fat in your liver. Inflammation and liver cell damage can cause fibrosis, or scarring, of the liver. MASH may lead to cirrhosis or liver cancer.

Experts are not sure why some people with NAFLD have MASH while others have simple fatty liver.