[Changes in body composition during various reducing diets].

Abstract

A method of measuring body density is presented which allows much greater precision in calculating the fat content of the human body than the usual methods of under-water weighing. Using this method, body fat was determined for three groups: normal weight, moderately overweight, and obese subjects. In spite of vast amounts of energy stored in the obese patient, no advantages for the pre- or post-surgical phase result. The explanation for this paradoxical situation is seen in two factors: 1. The cardiovascular system is not capable of delivering more energy because mobilisation of fat depends on corresponding oxygen intake. 2. Aside from this, a metabolic limiting factor exists in the mobilisation of protein reserves for the production of glucose, which leads to a considerable protein loss the first few weeks of a period of abstinence. In posttraumatic or post-operative situations, this protein mobilisation is particularly strong, especially when connected with a high metabolic intake. The high nitrogen loss and/or the high metabolic rate, is illustrated on the basis of severe skull and brain traumas. The differences between absolute fasting and a 200kcal-protein formula diet were experimentally investigated. The nitrogen loss under the protein diet was decisively less. An anabolic phase even reappeared after three weeks of the diet. The 200kcal-diet therefore represents a means of pre-operative weight reduction without protein loss. The alterations in body composition are almost exclusively the results of reduction in excess fat. This is demonstrated by means of clinical examples.