Doctors and health experts have warned against the common belief that non-alcoholic fatty liver disease is exclusive to obese patients, stressing that individuals with normal weight and even those who are lean are susceptible, in a phenomenon now known as "lean fatty liver."

According to a report published by Mayo Clinic, fatty liver occurs due to the accumulation of fat inside liver cells, and may over time progress to inflammation and fibrosis if not detected early and treated appropriately.

Hidden Risk Factors Behind the Disease

Data from the U.S. National Institutes of Health (NIH) indicate that obesity is not the sole cause of the disease; risk factors include genetic predisposition, insulin resistance, high triglycerides, type 2 diabetes, physical inactivity, diets high in sugars and sugary drinks, as well as metabolic disorders.

Visceral Fat: The Invisible Danger

Experts from the Harvard T.H. Chan School of Public Health confirm that some people appear outwardly lean, yet they have high amounts of visceral fat accumulated around internal organs—fat that is closely linked to an increased risk of fatty liver and heart disease.

Sugar May Be More Dangerous Than Weight

Mayo Clinic states that excessive consumption of sugars, especially sodas, sweetened juices, and sweets, prompts the body to convert excess sugar into fat stored in the liver, even in the absence of any significant weight gain.

Silent Symptoms and Accidental Discovery

In many cases, the disease causes no clear symptoms; however, some patients may experience persistent fatigue, mild pain or heaviness in the upper right side of the abdomen, elevated liver enzymes, and fat may be discovered incidentally during ultrasound scans or routine check-ups.

How Can It Be Prevented?

The American Association for the Study of Liver Diseases recommends a set of preventive measures, most notably: reducing sugars and sugary drinks, exercising regularly, improving dietary quality even with normal weight, treating diabetes and high lipid levels when present, and undergoing regular check-ups and medical follow-up.

Experts emphasize that leanness does not necessarily mean the body is free of harmful fat, and that maintaining liver health depends on a healthy lifestyle, quality of diet, and physical activity, not on weight alone.