Can fatty liver disease cause high blood sugar?

Fatty liver disease—specifically nonalcoholic fatty liver disease (NAFLD) and its more progressive form, nonalcoholic steatohepatitis (NASH)—is strongly associated with insulin resistance, a key driver of elevated blood glucose levels. While fatty liver itself does not directly *cause* hyperglycemia, it is both a marker and a contributor to systemic metabolic dysfunction. The accumulation of excess fat in hepatocytes impairs normal insulin signaling in the liver, leading to increased hepatic glucose production and reduced glucose uptake—both hallmarks of type 2 diabetes pathophysiology. In fact, up to 70% of individuals with type 2 diabetes have NAFLD, and conversely, people with NAFLD have a significantly higher risk—approximately two- to threefold—of developing prediabetes or type 2 diabetes over time. This bidirectional relationship underscores that fatty liver is not merely a passive consequence of obesity or poor diet but an active participant in dysregulated glucose metabolism. Clinical evaluation should therefore include assessment of fasting plasma glucose, HbA1c, and oral glucose tolerance testing when appropriate, especially in patients with known NAFLD.

Importantly, lifestyle interventions—including sustained weight loss (5–10% of body weight), regular aerobic and resistance exercise, and dietary patterns emphasizing whole foods, fiber, and unsaturated fats—can improve both hepatic fat content and glycemic control. In select cases, pharmacologic agents such as pioglitazone or GLP-1 receptor agonists may be considered not only for glycemic management but also for their demonstrated benefits on liver histology and inflammation in NASH. Early recognition and integrated management of fatty liver and glucose abnormalities are essential to mitigate long-term risks of cardiovascular disease, cirrhosis, and diabetes-related complications.