PATHOLOGICAL METABOLISM OF DIABETES 285 



of these diets. For diet III G is 118. This apparently innocent inter- 

 mediate isocaloric diet will cause glycosuria in a patient who is capable 

 of utilizing only 105 to 110 grams. Diet IV, with 300 more calories 

 than any of the others, has the same glucose equivalent as I and II and 

 would probably be borne as well as either. The question arises in respect 

 of diet IV as to whether the high fat is permissible or in any sense ob- 

 jectionable. Estimating the higher fatty acid value of this diet by means 



F A 



of the formula, it appears that F A is 152.3. G being 105, the ratio ^- 



is 1.45. As a general rule, acetone does not appear in the urine of un- 

 complicated cases of diabetes, or remain permanently, if present, until the 

 ratio reaches or exceeds 1.5 : 1 provided that the diet is completely utilized 

 and sufficient for maintenance so that endogenous factors of food sup- 

 ply do not complicate the calculation. Accordingly the quantity and pro- 

 portion of fat in diet IV are not necessarily too high for complete utiliza- 

 tion in the normal manner. 



5. Estimation of "Optimal" Caloric Diets. If C = = carbohydrate, 

 P = protein, F == fat, G = glucose and F A = higher fatty acids (plus 

 other ketogenic acids expressed in terms of higher fatty acid) in grams, the 

 quantity of glucose which any given food supply will introduce into the 

 metabolism is expressed by: (1) G = C + .5p-f- .1 F and the quantity 

 of higher fatty acids (and equivalents) may be expressed as: (2) 



FA 



F A = .44 P -j- .9 F. When the ratio 7=- exceeds a certain value for a 



(JT 



given case, ketonuria develops. Assuming for a given case that the ratio is 



.44 P + .9 F 



actually found in the neighborhood of 1.5, then - = =1.5 



C + .58 P -+- .1 F 



when the ratio of fatty acids to glucose is as high as it may be 

 without ketonuria. Simplifying, F == 2 C -f" .57 P, or simply (3) 



p. 

 F = 2 G H ' If it is assumed that the ratio F A : G shall not be al- 



2 



lowed to exceed 1.5, and that the relationships expressed in equations (1) 

 and (2) are as given, then to estimate the optimal food combination or diet 

 one may use equations (1) and (3). Given the quantity of glucose that 

 the patient can utilize completely (which must be found from his behavior 

 on some known diet), assign this value to G in equation (1). Thus 

 if 100 gm. is the highest quantity of glucose derived from all sources 

 that the patient can utilize completely at a given time, 100 grams 

 = C-f-.58P-{-.lF. In order to secure the maximal number of 

 calories, the diet must clearly contain every possible gram of fat (at 9 

 calories per gram) that the value of G and the relations expressed in (1) 

 and (3) will permit and consequently the lowest possible carbohydrate 

 protein fraction (at 4 calories per gram). Also as between carbohydrate 



