Observations on the Effect of Various Carbohydrates on the Ketosis of Starvation in Human Subjects

Abstract

IT is well known that in man after a relatively short period of starvation, or during a period of diet very low or entirely deficient in carbohydrate, a con- siderable ketosis appears. The time of onset of a positive nitroprusside reaction in the urine depends upon the composition of the diet prior to the commencement of starvation. A previous diet high in carbohydrate will postpone the ketosis whilst one high in fat and protein and low in carbo- hydrate will bring it on much more rapidly. Since during starvation the organism is thrown back upon its own tissues, it follows that what is going to happen will depend upon the composition of these tissues. Hence in fat subjects we expect a more rapid onset of ketosis than in thin subjects. This is well illustrated in the case of a starving fat woman investigated by Folin and Denis [1915]: This woman excreted after one day's fasting 270 mg. of acetoacetic acid and in succeeding days very large quantities of acetoacetic and hydroxybutyric acids. The professional faster Succi, who, according to Brugsch's description [1905], seems to have been a man of average build, produced much smaller quantities of the ketonic substances than the fat woman, even after very much longer periods of starvation. In general a man of medium build will not show a positive nitroprusside reaction in the urine in less than 30 hours of complete starvation (no food or drink). In our ex- perience of a considerable number of fasts the time varied from 20 hours after a previous diet low in carbohydrate to 36 hours after an average mixed diet.