In renal insufficiency the low-protein diet should be considered of reduction and temporary type. After clinical improvement it is advisable to place the patients on diet with a higher protein content and in this way to avert any further fall in the concentration of essential amino acids in the plasma and thus keep down the progressive protein-caloric fasting. The disturbance of the protein metabolism is, however, provoked not only by the protein-caloric deprivation, but by the disease itself. In this way, the developing upsets distort the picture of the protein-calorie deficiency, which finds its expression in the appearance of the anemic syndrome, disturbed electrolytes metabolism, imbalance of the acid-base equilibrium, etc. Therefore, one should look for other ways for their compensation, not believing that this can be achieved through the dietotherapy alone.