Caloric requirements after operation.

It has become clear since the original studies of Cuthbertson (1930) that the change in metabolism after injury involves an alteration in the internal environment and in the composition of the body, which is reflected in fluid and electrolyte metabolism, energy and intermediary metabolism and endocrine function (Moore & Ball, 1952). This is appreciated by the patient as loss of weight, diminished muscular strength and activity, and a temporary but definite decrease in intellectual application. The nutritional implications of these metabolic changes have been a major source of inquiry and much of the work has been directed towards two objectives. T h e main part has aimed at achieving a clear understanding of the mechanisms involved and of the factors which may influence the metabolic response to trauma. The other aspect has been principally clinical, dealing with the effect of these metabolic changes on the response of the patient to his management with particular emphasis on nutrition. It is with these two objectives in mind that this paper deals with the caloric requirements after operation.