Roughly 1.3 billion people worldwide have fatty liver disease, making it the most common liver condition on the planet. That works out to about 16% of the global population. In the United States alone, an estimated 100 million people (about 1 in 4 adults) are living with it.
Global Numbers at a Glance
A 2023 analysis published in The Lancet Gastroenterology & Hepatology estimated that approximately 1.3 billion individuals were living with fatty liver disease that year. The global prevalence rate of 16.1% means that if you gathered six random adults in a room, at least one of them would likely have excess fat stored in their liver. And the trend line points upward: modeling studies project a sustained increase in both prevalence and disease burden through at least 2035, driven largely by rising rates of obesity and type 2 diabetes.
How Common It Is in the United States
About 100 million Americans have fatty liver disease, according to the American Liver Foundation. That’s roughly 25% of the U.S. adult population. The condition is also the most common liver problem during pregnancy, affecting about 18% of pregnant women.
Prevalence isn’t evenly distributed across ethnic groups. Hispanic Americans have the highest rates, partly because of higher rates of obesity and diabetes in this population, and partly because of a genetic variant that increases susceptibility. White Americans fall in the middle. Black Americans have lower overall prevalence, but tend to experience worse outcomes once the disease takes hold.
Children Are Affected Too
Fatty liver disease is no longer just an adult problem. Globally, about 4.7% of adolescents had the condition as of 2019. Among children with obesity in the United States, the number jumps to 38%. Overall pediatric prevalence has increased 2.7 times since the late 1980s, tracking closely with the rise in childhood obesity.
Obesity and Diabetes Drive the Numbers
Weight is the single biggest predictor. Fatty liver disease is found in 75% of people who are overweight and in 90% of those with severe obesity. Type 2 diabetes is the other major driver: studies in Europe found that between 75% and 82% of people with type 2 diabetes also had fatty liver disease. Even people with prediabetes showed rates between 64% and 73%.
These overlapping conditions feed each other. Excess fat in the liver makes insulin resistance worse, which in turn promotes more fat storage in the liver. That’s a big part of why the numbers keep climbing alongside global obesity rates.
Most People Don’t Know They Have It
Fatty liver disease rarely causes symptoms in its early stages. There’s no pain, no yellowing of the skin, no obvious warning sign. Most people find out incidentally, when blood work or an imaging scan done for another reason reveals fat buildup in the liver. Given how few people are routinely screened, the true number of affected individuals is almost certainly higher than current estimates suggest.
When It Gets Serious
The basic form of the disease, where fat accumulates in the liver without significant inflammation, is considered relatively low risk on its own. But 20% to 30% of people with fatty liver progress to a more severe stage involving active inflammation and liver cell damage, previously called NASH and now known as MASH (metabolic dysfunction-associated steatohepatitis). This stage can lead to scarring, cirrhosis, liver failure, and liver cancer over time.
The challenge is that there’s no easy way to predict who will progress and who won’t. Obesity, type 2 diabetes, and older age all raise the risk of moving from simple fat buildup to the inflammatory stage.
Why the Name Changed
If you’ve seen the term “NAFLD” (nonalcoholic fatty liver disease) before, that name was officially retired in 2023. The condition is now called MASLD, short for metabolic dysfunction-associated steatotic liver disease. The change happened for a few reasons. The old name defined the condition by what it wasn’t (“nonalcoholic”), which wasn’t clinically useful. The word “fatty” was considered stigmatizing by many patients. And the new name better reflects what actually causes the disease: metabolic problems like insulin resistance, excess body weight, and abnormal cholesterol levels. You’ll still see “NAFLD” in older studies and some medical records, but it refers to the same condition.