Nonalcoholic fatty liver disease (NAFLD) is an illness most of us have never heard of, but it is more common than cirrhosis, and far more baffling. It is, for instance, strongly associated with being overweight or obese, and yet a significant proportion of sufferers are fit and lean. No one can explain why. Altogether about a third of us are thought to have early stages of NAFLD, but luckily for most of us it never progresses
