THE NORMAL DIET OF MAN 651 



with a total calorie value of 3348. His ration for war-time consists of : 



Protein 



Fat 



Carbohydrate 



145 grm. 



100 

 500 



corresponding to 3575 calories. Even this may be insufficient to supply the 

 energy needs during a period of intense muscular activity. In one experi- 

 ment by Atwater, in which the individual performed muscular work for a 

 period of sixteen hours out of the twenty-four in a calorimeter, the total 

 energy given out amounted to over 9000 calories in the course of the twenty- 

 four hours. It is probable, however, that in all cases where such excessive 

 calls on the energies of an individual are made, one or even two rest days 

 would follow the day of exertion, so that the deficiency of the food on the 

 day of exertion would be made good by an increased intake of food on the 

 following days. Thus three days' intake of 5000 calories would yield suffi- 

 cient energy for the output of 9000 calories on one day of exertion and of 3000 

 calories, the normal amount, on each of the two succeeding rest days. The 

 relative part played by the different constituents of a diet in yielding energy 

 to the body has been determined by many observers and especially in a long 

 series of researches by Atwater. In the following Table are given details 

 of the daily food in one such experiment on a man weighing 76 kilos : 



Very few accurate experiments have been made on the daily requirements 

 of women. Since the average weight of a woman is less than that of a man 

 and the work performed less severe, she will require a smaller amount 

 of food both to meet the energy expenditure of the body and to provide 

 for the repair of her tissues. Voit, under the assumption that the body 

 weight of woman is four-fifths that of man, and that her energy require- 

 ments are diminished in the same proportion, has given the following as the 

 daily requirements of a woman engaged in manual labour : 



