PATHOLOGICAL METABOLISM OF DIABETES 283 



hydrate and then with protein with a particular avoidance of fat as urged 

 by Joslin, would appear to be based on the supposition that if fat were 

 administered it would increase the catabolism of fat. But this would be 

 in disregard of the endogenous food supply. As the diet falls the endog- 

 enous supply rises to take its place, and vice versa. The lower the diet, 

 the less its significance in calculating the food supply from all sources. 

 It is possible to maintain the normal body with a diet that contains 

 but 10 per cent more calories than are produced in fasting, and the differ- 

 ence in metabolism of a man when receiving no diet and when receiving a 

 1500 calorie diet has been greatly overestimated by those who as a routine 

 employ fasting in the treatment of diabetes. 



3. Dealing with the Food Supply in Terms of Carbohydrate, Protein 

 and Fat. Carbohydrate, protein and fat are, as such, three separate and 

 distinct substances, no one of which can be expressed quantitatively in terms 

 of another and if we speak of food supplies or diets as made up of so much 

 carbohydrate, so much protein and so much fat, we simply name them 

 in terms of three variables. Thus each particular combination or diet 

 becomes a specific, and having learned by experience how one of them 

 will affect a certain patient, we have no means of knowing exactly how 

 a second dissimilar combination will affect the same patient, much less 

 another, except by trial and experience. The number of possible com- 

 binations of three variables is infinite and the number of practical food 

 combinations, no two of which will differ by less than 5 grams of one in- 

 gredient, or by less than 50 calories, runs into the thousands. Accord- 

 ingly if we attempt to correlate symptoms and signs shown by the patient 

 with the diet and follow the usual system of dealing with diets simply in 

 terms of carbohydrate, protein and fat, without attempting to resolve 

 them into simpler terms, it will be necessary to establish by experiment 

 the effects of each diet combination in every type of case. It would seem 

 tedious and hopeless to proceed by this inductive method. A further ob- 

 jection to this method, and a clear advantage in using another, lies in the 

 fact that protein, carbohydrate and fat as such are not the substances that 

 present themselves for the final oxidative attack in the body which results 

 in the liberation of energy. These substances are resolved by the proc- 

 esses of digestion and intermediary metabolism into simpler substances 

 before they can be burned in the tissues. It is not starch in the bowel nor 

 glycogen in the liver and muscles that taxes the endocrin function of the 

 pancreas, but the glucose into which these carbohydrates are resolved. 

 Protein of the diet ceases to be protein and becomes a mixture of amino 

 acids before it can be absorbed from the bowel and these undergo deamin- 

 ations, etc., prior to actual oxidation. Neutral fats may be absorbed in 

 part as such and are frequently deposited in the tissues as siich, but before 

 they can be oxidized and used as sources of e lergy, they must presumably 

 be saponified into glycerol and higher fatty acids. Thus, as a matter of 



