Nonalcoholic Fatty Liver Disease (NAFLD)

Moderate Evidence

Overview

Nonalcoholic Fatty Liver Disease (NAFLD) is a broad term for excess fat accumulation in the liver in people who consume little or no alcohol. It is now one of the most common liver conditions worldwide and is closely linked with insulin resistance, type 2 diabetes, central obesity, dyslipidemia, and metabolic syndrome. In recent years, many experts and organizations have also adopted the term Metabolic dysfunction-associated steatotic liver disease (MASLD) to better reflect its underlying metabolic drivers. The condition exists on a spectrum, ranging from simple liver fat buildup to more inflammatory and potentially progressive forms.

NAFLD may include simple steatosis—fat in the liver without substantial injury—or nonalcoholic steatohepatitis (NASH), in which fat accumulation is accompanied by inflammation and liver-cell injury. Over time, some individuals with NASH develop fibrosis (scarring), and advanced fibrosis can progress to cirrhosis, liver failure, or hepatocellular carcinoma. Although many people with NAFLD have no symptoms, some report fatigue, malaise, or vague right upper abdominal discomfort. The condition is often discovered incidentally through abnormal liver enzymes or imaging performed for other reasons.

From a public health perspective, NAFLD is significant because it is not only a liver disorder but also a marker of broader metabolic risk. Studies indicate that cardiovascular disease is a major cause of illness and death among people with NAFLD, and the condition is associated with increased risk of chronic kidney disease, sleep apnea, and endocrine-metabolic disorders. Prevalence estimates vary by population and diagnostic criteria, but global analyses suggest that roughly one in four adults may have fatty liver related to metabolic dysfunction, with rising rates in children and adolescents as well.

The causes of NAFLD are multifactorial. Research suggests that genetic predisposition, dietary patterns, sedentary behavior, gut microbiome changes, hormonal influences, and chronic low-grade inflammation all contribute. Risk is higher in people with obesity or diabetes, but NAFLD can also occur in individuals with normal body weight, sometimes described as lean NAFLD. Because disease severity cannot be determined by symptoms alone, clinical evaluation often focuses on identifying fibrosis risk and related metabolic conditions while ruling out other causes of liver disease.

Western Medicine Perspective

In conventional medicine, NAFLD is understood primarily as a metabolic and hepatic manifestation of systemic insulin resistance. Excess caloric intake, altered lipid handling, and impaired glucose metabolism can lead to fat deposition in liver cells. A subset of patients then develops oxidative stress, mitochondrial dysfunction, inflammatory signaling, and fibrotic remodeling. Current medical thinking places special emphasis on fibrosis stage as the strongest predictor of liver-related and overall outcomes.

Evaluation typically includes a review of alcohol intake, medications, viral hepatitis risk, and metabolic health, along with laboratory testing and liver imaging. Ultrasound is commonly used to detect steatosis, while noninvasive tools such as FIB-4, transient elastography, and fibrosis scores are increasingly used to estimate scarring risk. Liver biopsy remains the reference standard for distinguishing simple steatosis from steatohepatitis and staging fibrosis, but it is generally reserved for selected cases because it is invasive. Clinical management in mainstream practice generally centers on risk stratification, monitoring disease progression, and addressing associated conditions such as diabetes, elevated lipids, hypertension, and obesity.

Research on treatment has expanded rapidly, but evidence remains mixed across drug and supplement categories. Studies support the importance of weight reduction, improved dietary quality, and physical activity as central components of disease management, while certain medications may be considered in selected patients based on diabetes status, fibrosis risk, and specialist assessment. Conventional care also emphasizes surveillance for complications in advanced disease and coordination among primary care, endocrinology, hepatology, and cardiometabolic specialists. People with suspected or confirmed NAFLD are commonly advised to discuss evaluation and follow-up with a qualified healthcare professional, particularly because liver enzyme levels may be normal even when fibrosis is present.

Eastern & Traditional Perspective

Eastern/Traditional Medicine Perspective

Traditional East Asian medicine does not describe NAFLD using the same biomedical category, but its symptom patterns are often interpreted through frameworks involving phlegm-damp accumulation, liver qi stagnation, spleen deficiency, damp-heat, and blood stasis. In this view, impaired transformation and transport of fluids and nutrients may contribute to internal dampness and phlegm, while emotional stress, irregular eating patterns, and sedentary habits may disrupt liver and spleen function. Rather than focusing solely on fat within the liver, traditional systems generally assess the broader pattern of digestion, energy, circulation, sleep, and emotional balance.

In Traditional Chinese Medicine (TCM), clinical approaches have historically aimed to “resolve dampness,” “transform phlegm,” “soothe liver qi,” and “invigorate blood,” depending on the individual presentation. Herbal formulas and acupuncture are traditionally used within this pattern-based model, especially when NAFLD appears alongside fatigue, abdominal fullness, poor appetite, irritability, or metabolic imbalance. Modern Chinese clinical research has explored herbal combinations, acupuncture, and integrative care for fatty liver disease, with some studies suggesting improvements in liver enzymes, imaging findings, or metabolic markers; however, study quality is variable, and heterogeneity in formulas and methods makes broad conclusions difficult.

In Ayurveda, presentations resembling NAFLD may be discussed in relation to imbalances in meda dhatu (fat tissue), agni (digestive/metabolic fire), and accumulation of ama (metabolic waste), with the liver connected to broader processes of digestion, transformation, and heat. Naturopathic and traditional nutrition-oriented systems often frame fatty liver as part of a whole-body metabolic burden involving diet quality, inflammation, digestive function, and toxic load. Across these traditions, the emphasis is typically holistic and individualized. At the same time, because some herbal products may affect the liver or interact with medications, integrative care is generally considered safest when coordinated with a licensed healthcare provider familiar with both conventional and traditional approaches.

How They Relate

Condition / Treatment