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Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat accumulates in the liver of people who drink little or no alcohol. In June 2023, an international panel convened by major liver societies renamed the condition metabolic dysfunction–associated steatotic liver disease (MASLD) to better reflect its link to metabolic health and to reduce stigma. You may see both terms used; they describe the same disease.
NAFLD/MASLD exists on a spectrum:
NAFLD/MASLD is the most common chronic liver condition. Analyses of recent U.S. national survey (NHANES) data estimate that roughly a third of American adults have MASLD specifically, and that nearly 4 in 10 have some form of steatotic (fatty) liver disease overall. Worldwide, the prevalence of MASLD in adults is commonly cited at about 38%. Rates are projected to rise further as obesity and type 2 diabetes become more common.
Fatty liver develops when the body stores more fat in liver cells than it can process, a problem closely tied to insulin resistance and metabolic dysfunction. Under the current definition, a diagnosis of MASLD requires liver fat plus at least one cardiometabolic risk factor. Common risk factors include:
Other contributors include diets high in added sugars (particularly fructose) and ultra-processed foods, certain genetic variations, and family history. NAFLD/MASLD is more common in men and in Hispanic populations and somewhat less common in Black populations, differences thought to reflect both genetic and environmental factors.
It is also possible to have fatty liver at a normal weight ("lean MASLD"), so a healthy body weight does not rule it out.
NAFLD/MASLD is often called a "silent" disease because most people have no symptoms, especially in the early stages. When symptoms do appear, they are usually vague and may include:
As the disease advances to cirrhosis, more serious signs can develop, such as yellowing of the skin or eyes (jaundice), swelling in the abdomen or legs, easy bruising, and confusion. These are warning signs that warrant prompt medical evaluation.
Because symptoms are usually absent, NAFLD/MASLD is frequently discovered incidentally—through abnormal liver enzyme blood tests or imaging done for another reason. Diagnosis typically combines:
These tools help clinicians distinguish simple fatty liver from the more serious inflammatory form and identify who has significant fibrosis.
There is no quick fix, but the disease is often reversible in its early stages. Treatment focuses on the underlying metabolic problems.
Weight loss is the cornerstone. According to the NIDDK, losing 3% to 5% of body weight can reduce liver fat, while 7% to 10% can reduce inflammation and fibrosis. Weight loss should be gradual, since very rapid loss can worsen liver disease.
Lifestyle changes that help include:
Medications. In March 2024, the FDA granted accelerated approval to resmetirom (Rezdiffra), the first drug approved specifically for NASH/MASH. It is approved—alongside diet and exercise—for adults with noncirrhotic NASH who have moderate to advanced fibrosis (stages F2–F3); it is not for people with cirrhosis. It works by selectively activating thyroid hormone receptor-β in the liver. For people who also have type 2 diabetes or obesity, professional guidance supports certain other agents (such as semaglutide, a GLP-1 receptor agonist) for their metabolic and cardiovascular benefits. Any medication decision should be made with a clinician.
Notably, cardiovascular disease—not liver failure—is the leading cause of death in people with MASLD, so managing heart-disease risk is a central part of care. In advanced cirrhosis, liver transplantation may be considered.
Talk to a healthcare provider if you have risk factors such as obesity, type 2 diabetes, or metabolic syndrome, if blood tests show elevated liver enzymes, or if you experience persistent fatigue or upper-right abdominal discomfort. Seek prompt care for jaundice, abdominal swelling, or confusion. Early evaluation allows monitoring of fibrosis and timely treatment.
*This article is for informational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider about diagnosis and treatment.*
As of 2024, resmetirom (brand name Rezdiffra) is the first and only FDA-approved drug specifically for NASH/MASH, granted accelerated approval in March 2024 for use together with diet and exercise in adults with noncirrhotic disease who have moderate to advanced liver fibrosis (stages F2-F3); it is not approved for cirrhosis and works by selectively activating thyroid hormone receptor-beta. The most evidence-based first-line treatment for all stages remains gradual weight loss (3-5% of body weight reduces liver fat; 7-10% can reduce inflammation and fibrosis), a Mediterranean-style diet, regular physical activity, limiting alcohol, and controlling diabetes, blood pressure, and cholesterol. For people who also have type 2 diabetes or obesity, professional guidance supports certain GLP-1 receptor agonists such as semaglutide for their metabolic and cardiovascular benefits. There is no approved over-the-counter supplement that treats the disease; vitamin E and pioglitazone are sometimes used off-label in select non-diabetic patients only under specialist supervision. All medication and supplement decisions should be made with a qualified clinician. This information is educational and is not medical advice.
This page is for general information and is not medical advice. Always consult a qualified clinician about diagnosis and treatment. Individual results vary.