The dietary need for protein in a surgical patient depends mainly on the degree of preoperative and operative loss of protein reserves and the duration of convalescence. The greater the debilitation, the greater the need for protein replenishment, in order both to lessen surgical hazards and to hasten postoperative recovery. Effective therapeutic management requires, therefore, an optimal utilization of protein in conjunction with other dietary essentials, and, inasmuch as the nutritive, potentiality of a dietary protein is determined largely by its amino acid composition, tissue synthesis must depend, in turn, on the degree of utilization of these amino acids in the course of convalescence.
Although protein deficiency may not become evident untilthe later stages of undernutrition, it may be suspected earlier as a result of a careful dietary history and a record of a loss of weight. The causes of protein deficiency may be primary or secondary; i. e.,the