Non-alcoholic fatty liver disease (NAFLD), also known as metabolic (dysfunction) associated fatty liver disease (MAFLD), is excessive fat build-up in the liver without another clear cause such as alcohol use - with subsequent liver injury such as steatohepatitis, inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma. (See : Wikipedia )

It's the most common form of liver disease - estimated to affect more than a billion people worldwide.

Although it has 'associations' with obesity, type 2 diabetes, metabolic and insulin resistance syndrome and dyslipidemia, its direct causes are unknown.

A 2019 study published in the journal Cell Metabolism suggested that the disorder might be caused, in some instances, by the gut microbiome - especially naturally occurring yeasts - which can produce alcohol within the body.

See : Fatty Liver Disease Caused by High-Alcohol-Producing Klebsiella pneumoniae

Other suggested causes include sugary drink consumption, poor diet etc etc