From the British Liver Trust's dietary information sheet, for treating non-alcoholic fatty liver disease:
Non alcohol related liver disease is a term for a wide range of conditions in which there is a build-up of fat in the liver cells of people who do not drink alcohol excessively. Initially the fat deposits may not be associated with any symptoms, however, in some people this may progress to inflammation – non alcoholic steatohepatitis (NASH) which may in turn lead to scarring and cirrhosis.
You are more likely to develop a fatty liver if you:
are overweight or obese, particularly if you put on weight around your middle (apple shaped)
have high blood cholesterol
have diabetes
have been diagnosed with insulin resistance (where your body does not respond to insulin as it should).
If you have a fatty liver you may be advised to make changes to your diet and life-style including:
cutting out or down on alcohol (remember, alcoholic drinks are often high in calories
taking regular exercise, such as walking or swimming
eating plenty of fruit and vegetables
eating slow-release starchy foods, such as bread and potatoes
avoiding refined sugars and saturated fats – as in chocolate, cakes and biscuits.
if necessary, slowly reducing your weight to a healthy level for your build and age, and keeping it there.
If you are diabetic, then it is important to work with your doctor to keep your blood sugar levels under good control. If your blood cholesterol is high or you are insulin resistant, you may be prescribed medication as well given dietary advice.