Fatty liver, or hepatic steatosis, is a term that describes the buildup of fat in the liver. It’s normal to have some fat in your liver, but too much can become a health problem. The liver is the second largest organ in the body. Its function is to process everything we eat or drink and filter any harmful substances from the blood. This process is interrupted if too much fat is in the liver. Fatty liver is when fat accounts for more than 5 to 10 percent of your liver’s weight. View a BodyMap of the liver and learn more about its function. The liver commonly repairs itself by rebuilding new liver cells when the old ones are damaged. When there’s repeated damage to the liver, permanent scarring takes place. This condition is called cirrhosis. Fatty liver is a reversible condition that can often be resolved with lifestyle modifications. In many cases, fatty liver has no symptoms. It doesn’t usually cause permanent damage unless it progresses. Fatty liver is a common condition, affecting around 10 to 20 percent of Americans without cirrhosis or inflammation. Most cases of fatty liver are detected in people between ages 40 and 60, according to the American Liver Foundation. Fatty liver can become harmful to the liver if its underlying cause isn’t recognized and treated.