What symptom is primarily associated with fatty liver disease?

Extreme fatigue is primarily associated with fatty liver disease because this condition often leads to an accumulation of fat in liver cells, which can disrupt the liver's ability to function properly. When the liver is compromised, its capacity to metabolize fat and produce energy efficiently diminishes. As a result, individuals with fatty liver disease may experience a lack of energy and persistent fatigue, making it one of the most common symptoms reported.

In contrast, sudden weight gain is less specific and can be attributed to various other health issues, not just fatty liver disease. Rapid heart rate may occur in many different conditions and is not directly linked to liver health. Increased appetite is also not a typical symptom of fatty liver disease, as the metabolic imbalances and the overall impact on energy levels often result in a reduced desire to eat rather than an increase.