What is NAFLD? No, it is not a political party. It is Non-alcoholic Fatty Liver Disease. Srinivasan Ramani Nonalcoholic fatty liver disease, or NAFLD is a condition in which excess fat builds up in your liver . This buildup of fat is not caused by heavy alcohol use. When heavy alcohol use causes fat to build up in the liver, this condition is called alcohol-associated liver disease . If you already have diabetes, NAFLD increases your chance of developing heart problems.