Protein
Most of the waste products excreted by the kidney come from the protein in the diet. Patients with CRF are therefore often advised to restrict protein in their diet. However, it must be remembered that body uses protein to build, maintain, and repair body tissues. It is therefore very essential to maintain sufficient protein intake.

Calories
Most people with kidney disease need sufficient calories to maintain their weight. Taking high calorie food may increase the level of fat in the blood. A high level of fat (triglyceride) has been observed in many cases of CRF. This may predispose to an increased risk of heart attack and paralysis due to clogging of blood vessels by the fat.

Sodium
Diseased kidney cannot always control sodium excretion. In most kidney diseases, sodium is not normally excreted leading to sodium retention which in turn results in high blood pressure and swelling.

Potassium
With advanced kidney damage, potassium eaten in an "average" diet cannot be excreted by the kidneys. This can lead to high potassium concentration in the blood which can cause serious heart problems.

Fluids
In most cases of advanced kidney disease, the urine output drops. When this happens, it is necessary to restrict the intake of liquids (fluids). The excessive fluid intake results in swelling, high blood pressure and difficulty in breathing. It is important to remember that everyone's diet will be different because of different forms kidney diseases.