With age or in the later stages of various renal diseases, the ability of the remaining kidney units to remove metabolites from the body decreases significantly due to the loss of function of most tissues, so it is necessary to strictly optimize the dietary intake of patients in order to reduce the production of metabolites in the body and reduce the workload of the remaining kidney tissues. Optimizing the diet of patients with renal failure is a systematic project, and I will explain it in the form of questions and answers for easy understanding.