There is no definitive answer as to how long a patient with severe fat can live, because simple fatty liver can be reversed with certain treatment measures, and fatty liver itself does not cause death. The main reason why patients worry about the impact of fatty liver on life expectancy is that fatty liver can develop into cirrhosis to a certain extent, which can later cause a series of complications, including acute upper gastrointestinal bleeding, hepatic encephalopathy, hepatorenal syndrome, and even death. However, severe fatty liver can be reversed. Fatty liver can be divided into alcoholic fatty liver and non-alcoholic fatty liver. By adjusting the diet and abstaining from alcohol, together with some drugs for fatty liver, including reduced glutathione, polyenyl phosphatidylcholine and metformin, most patients can be reversed, and the reversal will not affect their life expectancy. However, if the disease is not well controlled and develops into cirrhosis, life expectancy may be affected, but the exact length of life depends on a variety of factors such as individual differences, response to treatment, and the degree of patient cooperation, and may be years or decades.