Dietetics is concerned with providing information and guidance on nutrition.
There are two forms:
Nutritional advice or education means that advice is given about nutrition when there is no medical problem.
Diet advice is given when there is a disease or illness. Think of diabetes, obesity, underweight, intestinal complaints, high cholesterol, cardiovascular diseases, allergies etc.
Whether a nutritional or dietary advice is given, in both cases we try to take into account your personal circumstances and wishes as much as possible.