THE PROTEIN METABOLISM OF MANKIND 



71 



It would therefore appear that in the different countries 

 where dietary studies have been carried out, those who have a 

 free choice of food arrange to eat such quantities as shall permit 

 of at least 100 grammes of protein intake daily. It is uncommon 

 to find much below this figure except in conditions of poverty ; 

 thus factory girls in Leipsic and sewing girls in London earning 

 poor wages have been shown to live on diets yielding little over 

 50 grammes of protein and less than 2,000 calories of total energy. 

 When muscular work is excessive or fatiguing, there is a great 

 demand for a high caloric and protein value of the diet. This 

 is recognized in the framing of the army rations of the different 

 nations in peace and war : 



CALORIC VALUE OF RATIONS.* 



The requirements of the body for increased protein and energy 

 during severe muscular exertion is well exemplified in Atwater's 

 standards, which embody the results of modern investigations 

 into the diet of adults under different conditions : 



Taking the average weight of Europeans and Americans at 

 68 to 70 kilos, or about 11 stone, the standard dietary for a 

 man doing a moderate amount of work should offer 14 to 1-7 

 grammes of protein and 40 calories per kilo of body weight. 



Turning now from dietaries of the European and American 

 type, on which an immense amount of work has been done, let 



* Spriggs, " Sutherland's System of Diet and Dietetics." London, 1908. 



