Fatty liver disease is more dangerous than most people think, but the main threat comes from the heart, not the liver. Serious liver complications such as cirrhosis or liver cancer affect only a small minority after many years. The evidence for the cardiovascular risk is well supported by multiple independent studies; the practical course of action is lifestyle change, because approved medications do not (yet) exist.
Fatty liver disease, nowadays also referred to as MASLD or NAFLD, is one of the most common chronic liver conditions in the world: more than a quarter of all adults are affected. Most people are unaware of this, because the condition almost never causes symptoms. There may occasionally be some fatigue or a feeling of fullness in the upper abdomen, but in the vast majority of cases it is only discovered by chance, through a blood test or an ultrasound scan.
The greatest threat posed by a fatty liver is not the liver itself, but the heart. Several large cohort studies show that cardiovascular disease is the leading cause of death in people with fatty liver disease, and that this risk is elevated independently of classical risk factors such as high blood pressure and high cholesterol. Cardiac arrhythmias, calcification of heart valves and a weakened heart muscle also occur more frequently. Anyone with a fatty liver would therefore do well to take the heart at least as seriously as the liver.
Serious liver complications are less common, but not impossible. Of people with fatty liver disease, only 3 to 5 percent ultimately develop cirrhosis, scar tissue in the liver, and that process typically takes more than twenty years. In the most advanced cases, cirrhosis can lead to liver cancer (hepatocellular carcinoma), but that is a rare and late complication. Most people with a fatty liver never reach that stage.
Whether someone belongs to the small group that does progress depends on several factors simultaneously: insulin resistance, an unhealthy diet, a disrupted gut microbiome and genetic predisposition all play a role. Abdominal fat is a particularly important factor here: up to eighty percent of people with fatty liver disease are overweight, and fat accumulation around the organs in particular delivers harmful fatty acids and inflammatory substances directly to the liver.
At the time of the available research, there was no approved medication for fatty liver disease. Drugs under development appeared to have only a modest effect. Treatment therefore relied entirely on lifestyle change: a healthier diet, weight loss and more physical activity. That is also the immediate practical takeaway: losing weight and reducing abdominal fat addresses both the liver risk and the heart risk at the same time.
Based on several large international cohort studies and systematic reviews (PMID 35418240, 32044314, 29858436, 39243773, 32321858, 34069012, 25071327). The severity of the cardiovascular risk is well supported by multiple independent studies. The progression figures for cirrhosis and liver cancer are based on observational research.