Fatty liver disease has quietly become one of the most widespread chronic conditions in the country, and the reason it stays hidden is unnerving.
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), about 24% of US adults have nonalcoholic fatty liver disease, now formally called metabolic dysfunction-associated steatotic liver disease (MASLD).
More recent modeling published in January 2025 by researchers estimating the US disease burden put the 2020 figure even higher, at 33.7% of US adults, or roughly 86.3 million people. The projection sees that share climbing to 41.4% by 2050.
The trouble is how quiet the disease is. NIDDK notes that many people with NAFLD have no symptoms at all in the early stages.
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The liver has no pain fibers of its own, so early fat buildup and inflammation cause nothing a person can feel. By the time symptoms arrive, scarring has often already set in.
Why most cases go unnoticed for years
The clinical picture is thin in the early stages, and that is the point of most concern for physicians.
A StatPearls clinical reference states that most patients with MASLD are asymptomatic, and fatigue is one of the most common presenting symptoms when anything shows up at all.
That mismatch, between how common the disease is and how quiet it is, is why many people first learn of it through a routine blood test or an ultrasound ordered for another reason.
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The 7 signs worth taking seriously
1. Persistent fatigue you cannot explain. NIDDK lists feeling tired among the few early symptoms of NAFLD. It is easy to attribute to sleep, work or age, but if it lingers, it is worth mentioning to a doctor.
2. Discomfort or fullness in the upper right abdomen. NIDDK also identifies "discomfort in the upper right side of your abdomen" as a possible early symptom.
StatPearls notes a "sharp or dull aching upper abdominal pain" among nonspecific complaints. This is the area directly over the liver.
3. An enlarged liver found on a physical exam. Most patients feel nothing, but a doctor pressing under the right rib cage may notice hepatomegaly.
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The Merck Manual professional edition reports that hepatomegaly develops in approximately 75% of patients with the inflammatory form, metabolic dysfunction-associated steatohepatitis (MASH).
4. Elevated liver enzymes on routine blood work. NIDDK notes that a doctor "may suspect you have NAFLD if your blood test shows increased levels of the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST)." That is often how a diagnosis begins, not with a symptom.
5. Spider-like blood vessels on the skin. These small red vessels branching out from a central point, called spider angiomas, are listed in the StatPearls reference among physical findings tied to advanced liver disease.
6. An enlarged spleen. In its guide to diagnosing NAFLD, NIDDK says physicians look for signs of cirrhosis during the exam, including an enlarged spleen. Splenomegaly is often the first sign of portal hypertension developing behind the scenes.
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7. Swelling in the abdomen from fluid buildup. NIDDK's diagnosis guide lists ascites, a buildup of fluid in the abdomen, among the signs of cirrhosis clinicians look for on exam. It is a late signal, not an early one.
The first six can be brushed aside as nothing, or picked up only when a clinician goes looking. The seventh usually arrives after significant damage.
Who is most at risk
Risk climbs sharply with weight and metabolic health. According to NIDDK, up to 75% of people who are overweight and more than 90% of people with severe obesity have NAFLD.
One-third to two-thirds of people with type 2 diabetes are affected. High triglycerides, low HDL, high blood pressure and elevated blood glucose, the warning signs of metabolic syndrome, all raise the risk.
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Hispanic Americans have the highest rates in the United States, followed by non-Hispanic white and Asian American adults, per NIDDK.
What to do if any of these apply to you
There is no drug most people with MASLD need to take at the earliest stage.
Managing weight, blood sugar, blood pressure and cholesterol addresses the underlying drivers. NIDDK also notes that researchers are studying whether diets high in fructose may increase NAFLD risk.
Anyone with persistent fatigue, right-sided abdominal discomfort or a family history of metabolic disease should ask their primary care doctor about a liver enzyme panel and, if warranted, a FIB-4 or APRI score.
Those simple calculations, drawn from routine blood work, help identify people at higher risk of advanced fibrosis. For the earlier version of the same conversation about liver symptoms, see the 8 warning signs your liver may be in trouble.
An ultrasound is the usual first imaging test if fatty liver is suspected, and it can be scheduled through a primary care office.
This article is made and published by Mie Hermansen, who may have used AI in the preparation.