502 METABOLISM IN FASTING 



the energy consumption be determined in proportion to the 

 kilogram of body weight a striking uniformity becomes evi- 

 dent, about 28 to 32 calories pro kilogram for the twenty- 

 four hours. In case of rest in bed the minimal requirement 

 of a human being was determined as somewhat less by Tiger- 

 stedt and by Johansson, twenty-two to twenty-five calories 

 daily pro kilogram. Atwater and Benedict found in fasting 

 human beings resting in bed an energy consumption of 

 twenty to twenty-one calories by direct calorimetry ; Zuntz, 

 in case of an individual accustomed to a diet very low in 

 protein (consisting of potatoes and butter), at absolute rest 

 and fasting, met with a twenty-four hour energy consump- 

 tion of only about nineteen calories pro kilogram. 46 Ob- 

 servations of the respiratory metabolism and nitrogen out- 

 put have shown, further, that not only the total expenditure 

 of energy but also the amount of protein and fat, which 

 provides the latter, are fairly constant in the body. It should 

 be noted, too, that the economy begins its actual fasting state 

 only after the lapse of several days, after the greater glyco- 

 gen deposits have been consumed. The constancy of the 

 exchange in inanition is, however, not confined merely to 

 human beings. E. Voit found in case of all warm blooded 

 animals studied a relative uniformity of energy requirement 

 in inanition if it be determined for the unit of surface. 47 1 1 1 

 conclude directly," says Eubner, "that the developing ani- 

 mal in its growth manifests a very varying intensity of gen- 

 eral metabolism in inanition, but that invariably the intensity 



46 N. Zuntz, Centralbl. f. Physiol., 26, 725, 1912. 



47 Note: "The minimal maintenance work of the fattened and the non- 

 fattened growing animal," says Tangl, in a study of the minimal maintenance 

 effort of the hog (Biochem. Zeitschr., 44, 278, 1912), "show scarcely any 

 difference, when calculated on the basis of the surface extent of the body; cal- 

 culated on the basis of body weight it is greater for the growing unfattened 

 animal. As an average it is for the fattened, pro kilogram 19.6 calories, pro 

 square metre 1060 calories; for the unfattened, pro kilogram 27.2 calories, 

 pro square metre 1100 calories. It is in each instance noteworthy that in spite 

 of the difference in the amount of fat in the fattened and unfattened animals 

 the maintenance work determined on the basis of a unit of body surface is 

 the same . . ." 



