Patients with kidney disease comprise a very heterogenous group of clinical presentation; there is no uniform “nutrition in kidney disease,” and nutrition must be meticulously adapted to the stages of renal insufficiency and the undertaken therapy. In early stages of acute kidney injury (AKI) and chronic kidney disease (CKD), it’s all about protecting the kidney from further injury, which includes several metabolic aspects. An inappropriate diet in these early phases actually can actually aggravate renal injury, increase the need of renal replacement therapy (RRT), and worsen outcome. The long-held dogma of performing full nutrition and accepting the need of RRT definitely has to be refused. In later phases, the multiple similar metabolic alterations in AKI and CKD have to be considered in designing a nutrition program. Finally in the failure stages of AKI and CKD with need of RRT, the complex impact of RRT on metabolism and nutrient requirements by therapy-associated nutrient losses have to be taken into consideration.