650 PHYSIOLOGY 



made to arrive at some idea of the average amounts of food required by a 

 working man have been based not so much on scientific experiment as on an 

 analysis and comparison of the diets in general use among different classes of 

 men, the amounts of which are determined by the instinct of the man himself, 

 while its quality is limited by his daily earnings. Tigerstedt divided the 

 different diets which have been investigated into six classes, according 

 to the total amount of energy which each of them represents. These are 

 as follows : 



In view of this great variation among the diets of different individuals it 

 becomes difficult to arrive at any conclusion as to the diet which should be 

 regarded as the average and should guide us in drawing up dietary scales for 

 public institutions. Voit, from experiments on ordinary workmen per- 

 forming eight or nine hours' labour a day, such as a bricklayer or carpenter, 

 has laid down the following as an average diet, namely : 



Protein 



Fat 



Carbohydrate 



118 grm. 

 56 



500 



This would correspond to a total calorie value of 3055, or, subtracting 

 10 per cent, for the food which is not utilised in the alimentary canal, to 

 2749 calories. The fat in this diet is rather low, preference being given to 

 the carbohydrate on account of its greater cheapness. It is not advisable 

 to reduce the fat below this limit, since the human body has a need for a 

 certain proportion of fat, in the absence of which the utilisation of the other 

 food-stuffs does not proceed normally. The presence of fat in the diet is 

 especially important in the case of infants and young children, many of the 

 disorders of nutrition prevalent among the children of the lower classes being 

 largely determined by the absence of the proper quantity of fat from the 

 diet. In the case of severe work this diet may not be adequate to supply 

 the necessary quantity of energy. Thus, for soldiers, Voit's ration during 

 manoeuvres consists of : 



Protein 



Fat 



Carbohydrate 



135 grm. 

 80 

 500 



