It is estimated up to one in every three people in the UK has early stages of NAFLD, where there are only small amounts of fat in the liver.
According to the NHS, early-stage NAFLD does not usually cause any harm, but it can lead to serious liver damage, including cirrhosis, if it gets worse.
Having high levels of fat in the liver is associated with an increased risk of serious health problems such as diabetes, high blood pressure and kidney disease.