Using data from the Third National Health and Nutrition Examination Survey (NHANES III), we estimated the prevalence of nonalcoholic fatty liver disease (NAFLD) among U.S. adults. "The prevalence of NAFLD was 19% in the general population, and NASH was present in 2%" of adults. NAFLD was defined histologically as more than 5% of hepatocytes containing macrovesicular fat in the absence of other chronic liver diseases.

In this analysis of 10,000+ adults in NHANES cycles from 1988–2016, NAFLD was defined by the presence of hepatic steatosis with no other causes of chronic liver disease. The authors report: "The prevalence of NAFLD among US adults increased from 20.0% (1988–1994) to 30.0% (2011–2016)." They note that this corresponds to roughly one-third of adults having excess liver fat consistent with NAFLD in the most recent survey cycles.

This review states that the prevalence of nonalcoholic fatty liver disease (NAFLD) in the United States is 38%, and that more recent estimates place the period prevalence among adults at 23% to 32%. It also says that more than one-third of adults have NAFLD, showing that a one-third figure is within the range used in the literature.

In an analysis of NHANES III data (1988–1994), the authors state: "The age-adjusted prevalence of hepatic steatosis was 21.4% (95% CI: 19.7, 23.1), which corresponds to 32.5 (95% CI: 29.9, 35.0) million people in the United States." They further note: "In this cross-sectional, nationally representative study, we found that hepatic steatosis detected by ultrasonography was present in almost 32.5 million adults or 21.4% of the US noninstitutionalized population aged 20–74 years."

This study evaluates MRI–proton density fat fraction (PDFF) against liver biopsy in NAFLD/NASH patients. In the context section, the article cites population data: "Nonalcoholic fatty liver disease affects approximately 30% of adults in the United States" and is strongly associated with obesity and metabolic syndrome. NAFLD is characterized by "excessive fat accumulation in hepatocytes" typically defined histologically by ≥5% steatosis.

The CDC page gives the percent of adults age 18 and older with diagnosed liver disease as 1.8% (4.5 million adults). This is not a fatty-liver-specific measure, but it shows that diagnosed chronic liver disease is far lower than one-third of adults.

In NHANES 2017–2018, prevalence of steatosis (CAP ≥302 dB/m) was estimated at 28.6%, and after excluding other causes of liver disease, the estimated prevalence of presumed NAFLD was 25.6%. The paper also reports that using imaging-based noninvasive tests, prevalence estimates for NASH among US adults ranged from 1.3% to 4.8%.

The article states that the prevalence of nonalcoholic fatty liver disease in the United States is 38%. It also notes that the latest estimates for adult prevalence across studies range from 23% to 32%, and that a more recent meta-analysis found a prevalence of 38%.

The study reports that the weighted national prevalence of NAFLD in U.S. adults was 26.7% (95% confidence interval: 25.3% to 28.1%). This is below one-third and provides a lower estimate from a national analysis.

This meta-analysis reports that the estimated global prevalence of NAFLD among adults is 32%, and that prevalence exceeds 40% in the Americas and South-East Asia. It also notes that a more recent U.S.-based meta-analysis found prevalence at 47.8%, indicating that U.S. estimates can be substantially higher than one-third depending on methodology.

In a meta‑analysis of 86 studies including over 8.5 million individuals, the pooled NAFLD prevalence in North America was 24.1%. The authors state: "The prevalence of NAFLD in North America and Europe is approximately 23–25%," but also note a rising trend over time linked to obesity and diabetes. NAFLD is defined as "excessive hepatic fat accumulation" usually measured by imaging or histology, corresponding to liver fat above normal physiological levels.

This study evaluated MRI‑PDFF for quantifying liver fat in 50 obese patients undergoing bariatric surgery. "The prevalence of NAFLD in the investigated cohort was as high as 94%. Histologic hepatic steatosis grades 0, 1, 2, and 3 were observed in 3 (6%), 25 (50%), 14 (28%), and 8 (16%) of 50 obese patients, respectively." MRI‑PDFF values around 16.8% distinguished mild (grade 0–1) from more advanced (grade ≥2) steatosis, demonstrating how excess liver fat is quantified in clinical research.

The paper notes that "Non-alcoholic fatty liver disease (NAFLD) is a worldwide public health issue affecting 20%–30% of adults" and is especially common in obese individuals. It explains that MRI‑PDFF "has emerged to be a promising tool in quantification of liver fat" and correlates strongly with magnetic resonance spectroscopy. In their cohort of suspected NAFLD patients, MRI‑PDFF revealed steatosis Grade 0 in 28% and Grade I–III (excess fat) in 72%, illustrating how liver fat burden is distributed in at‑risk populations.

The introduction states: "Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common cause of chronic liver disease worldwide, affecting over 30% of the global general population and up to 75% of obese individuals." The authors describe MRI‑PDFF as "the most accurate noninvasive method for quantitatively assessing liver fat" but note its limited availability. Their cohort of 94 patients had a mean liver MRI‑PDFF of 3.8% (range 0.2–22.3%), and their deep‑learning approach aimed to infer these excess fat levels from CT scans.

In this NHANES 2009–2018 analysis, the authors report: "The incidence of MAFLD was significantly greater (P < 0.001) in males (39%) than in females (29.2%)." They further note that MAFLD (metabolic dysfunction‑associated fatty liver disease) is defined based on evidence of hepatic steatosis plus metabolic risk, and that overall prevalence in U.S. adults approaches roughly one‑third when both sexes are combined over the study period.

Focusing on lean adults, the study notes: "Our results show that the age-adjusted prevalence of lean NAFLD among US adults is 6.30%, while using the FAST score and TE we found the prevalence of high-risk NASH and significant fibrosis to be 1.29% and 4.35%, respectively." It also reports ethnicity-specific NAFLD prevalences among lean individuals, but this subgroup analysis implies that total NAFLD prevalence in the whole adult population is substantially higher than 6.3%.

This report says the new research found MASLD is quite widespread, affecting 4 out of 10 adults, and gives an estimated prevalence of 42% in U.S. adults. That is higher than one-third and reflects a newer estimate using updated terminology for fatty liver disease.

NYU Langone says NAFLD affects nearly one third of Americans and gives an estimated prevalence of 30% among American adults. The page attributes the condition to excess fat buildup in the liver and links it to obesity and type 2 diabetes.

Reporting on an NHANES transient elastography study, the article states that the "prevalence of metabolic dysfunction-associated steatosis liver disease (MASLD) was statistically different between the confirmed, possible, and no cACLD groups (61% vs 59.1% vs 22.4%)," highlighting that steatotic liver disease is common among patients with advanced chronic liver disease and present in over one‑fifth of those without cACLD. While focused on advanced disease, it supports the broader context that hepatic steatosis and MASLD are prevalent conditions in U.S. adults.

The page states that about 24% of U.S. adults are estimated to have MASLD and that about 80 to 100 million people in the U.S. have MASLD. It also notes that one study of 2017-2020 NHANES data estimated MASH prevalence among U.S. adults at 1.3% to 4.8%.

The page says that about 100 million people, or about 25%, in the United States are estimated to have MASLD, previously called NAFLD. It also defines fatty liver as having more than 5% to 10% of the liver's weight as fat.

UCLA Health states that in the United States the prevalence of fatty liver disease ranges from 10% to 46%. It also says systematic reviews suggest NAFLD prevalence in adults is probably 25% to 33%, while NASH prevalence is 2% to 5%.

In the NHANES III analysis frequently cited in later work, the authors conclude: "The prevalence of hepatic steatosis was 21.4% in the United States adult population," and that "approximately 32.5 million adults" had hepatic steatosis at that time. This older estimate, based on ultrasound, is lower than more recent elastography-based estimates but establishes that about one‑fifth of U.S. adults already had excess liver fat in the late 20th century.

This public health page says NAFLD affects 1 in 4 Americans and is the most common cause of liver dysfunction. It also states that the prevalence is higher among persons with obesity and type 2 diabetes than in the general population.

Clinical and epidemiologic estimates vary because studies use different definitions (NAFLD, MASLD, MASH), different populations, and different measurement methods. U.S. adult prevalence figures commonly cited in recent reviews range from about 24% to 38%, while some newer analyses and reports place it around 40% or higher.

The page says experts estimate about 25% of adults have fatty liver disease, which occurs when abnormal amounts of fat build up in the liver. This is presented as a general estimate rather than a study result.

The abstract reports an estimate that between 1 in 3 and 1 in 2 adults have hepatic steatosis. Although this paper appears to concern Canada rather than the United States, it is relevant as a comparator for how prevalence estimates can vary by method and population.