PHYSICAL AND PHYSIOLOGICAL MEASUREMENTS. 103 



compared with a lean period in a steer does not seem to invalidate the 

 conclusion that human individuals who are relatively tall for their 

 weight have a higher metabolism than shorter ones. In the case of 

 the fattening experiment reported by Armsby and Fries the experi- 

 mentally induced changes in the nutritional level of the animal were 

 brought about with relatively great rapidity. Concomitant with the 

 fattening there was an increase of 36 per cent in the basal katabolism, 

 just as in the case of a man undergoing a 31-day fast at the Nutrition 

 Laboratory there was a 28 per cent decrease in the basal katabolism. 2 

 Without further evidence one would not be warranted in assuming that 

 like differences would necessarily be found between different individuals 

 of relatively permanent lean and fat physical constitution. 



More recent investigations have shown that the basal metabolism 

 of the human subject is profoundly affected by sudden modifications 

 of the nutritional level, particularly those which are accompanied by 

 rapid reduction in body-weight. If the food-intake be reduced below 

 the maintenance level it is plain that with constant basal requirements 

 there must be draft upon previously stored body-reserves. 



Experiments with human subjects along this line demand a high 

 degree of personal integrity and veracity on the part of the subjects. 

 Such requirements were fulfilled by two squads of 12 men each from 

 the International Y. M. C. A. College at Springfield, Massachusetts. 3 

 The first squad was kept for a period of 4 months upon a much re- 

 stricted diet with an energy content of approximately one-half to two- 

 thirds of the caloric requirements prior to the test. During the first 

 few weeks there was a pronounced decrease in body- weight. After the 

 body-weight had fallen on the average 12 per cent, an increase in the 

 diet was made to prevent further loss in weight. Measurements of 

 the groups as a whole in the large respiration chamber at the Nutrition 

 Laboratory in which the 12 men slept every alternate Saturday night 

 gave the basal metabolism during deep sleep. 



The normal demand of the men prior to the reduction in diet 

 ranged from 3200 to 3600 net calories. After a decrease of 12 per cent 

 in weight only 1950 calories were required to maintain this weight. 



The heat output as measured by indirect calorimetry and on the 

 basis of calories per kilogram of body-weight and calories per square 

 meter of body-surface was essentially 18 per cent lower than at the 

 beginning of the study. Throughout the period of loss in weight and 

 for some time following there was a marked loss of nitrogen. In round 

 numbers these men lost approximately 150 grams of nitrogen. The 

 nitrogen output per day at the maintenance diet of 1950 net calories 



2 Benedict, Carnegie Inst. Wash. Pub. No. 203, 1915. Also Am. J. Physio!., 1916, 41. p. 292. 



3 Benedict; Proc. Amer. Phil. Soc., 1918, 57, p. 479. Also Benedict and Roth, Proc. Nat. 



Acad. Sci., 1918, 4, p. 149. Also Benedict, Roth, Miles, and Smith, Carnegie Inst. 

 Wash. Pub. 280. (In press). 



