Fatty liver disease (FLD), also known as hepatic steatosis and steatotic liver disease (SLD), is a condition where excess fat builds up in the liver. Often there are no or few symptoms. Occasionally there may be tiredness or pain in the upper right side of the abdomen. Complications may include cirrhosis, liver cancer, and esophageal varices. The main subtypes of fatty liver disease are metabolic dysfunction¨Cassociated steatotic liver disease (MASLD, formerly "non-alcoholic fatty liver disease" (NAFLD)) and alcohol-associated liver disease (ALD), with the category "metabolic and alcohol associated liver disease" (metALD) describing an overlap of the two. The primary risks include alcohol, type 2 diabetes, and obesity. Other risk factors include certain medications such as glucocorticoids, and hepatitis C. It is unclear why some people with NAFLD develop simple fatty liver and others develop nonalcoholic steatohepatitis (NASH), which is associated with poorer outcomes. Diagnosis is based on the medical history supported by blood tests, medical imaging, and occasionally liver biopsy. Treatment of NAFLD is generally by dietary changes and exercise to bring about weight loss. In those who are severely affected, liver transplantation may be an option. More than 90% of heavy drinkers develop fatty liver while about 25% develop the more severe alcoholic hepatitis. NAFLD affects about 30% of people in Western countries and 10% of people in Asia. NAFLD affects about 10% of children in the United States. It occurs more often in older people and males.

Reference
Wiki: Non-alcoholic fatty liver