Some people with liver disease must eat a special diet. This diet helps the liver function and protects it from working too hard. Proteins normally help the body repair tissue. They also prevent fatty buildup and damage to the liver cells.
Advise is a verb, and advice is a noun. So advice is what is given, while the act of giving advice is called advising (or to advise).
advise. vb (when tr, may take a clause as object or an infinitive). 1. to offer advice (to a person or persons); counsel: he advised the king; to advise caution; he advised her to leave. 2. (sometimes foll by: of) to inform or notify. 3. (foll by: with) US to consult or discuss.