Renal edema is characterized by the fact that it occurs first in areas with loose tissue, such as the eyelids or face, ankles, and is evident in the morning, and in severe cases it can involve the lower extremities and the whole body. The nature of nephrogenic edema is soft and mobile, and clinically it presents as depressed puffiness, i.e., depressions appear when the skin is pressed locally with a finger. When edema occurs, the diet should also pay attention to the following points: restrict water, sodium and protein intake 1. 146.4kJ/kg (30~35kcal/kg) per day. 2. Water and salt intake Mild edema with urine volume less than 1000ml/d does not require excessive water restriction, and sodium is limited to 3g/d or less, including sodium-containing foods and drinks. For severe edema with oliguria, daily water intake should be limited to less than 1000ml, and a salt-free diet should be given (sodium content in main and side dishes is less than 700mg per day).