FOODS 



85 



lungs in the form of carbonic acid, from 250 to 280 grammes of 

 carbon per diem. During the same time he will ehminate, chiefly 

 in the form of urea in the urine, about 15 to 18 grammes of nitrogen. 

 These substances ai*e derived from the metabolism of the tissues, 

 and various forms of energy, work and heat being the chief, are 

 simultaneously liberated. During muscular exercise the output of 

 carbon greatly increases ; the increased excretion of nitrogen is not 

 nearly so marked. Taking, then, the state of moderate exercise, it is 

 necessary that the waste of the tissues should be replaced by fresh 

 material in the form of food ; and the proportion of carbon to 

 nitrogen should be the same as in the excretions : 250 to 15, or 16'6 

 to 1. The proportion of carbon to nitrogen in proteid is, however, 

 53 to 15, or 35 to 1. The extra supply of carbon must come from 

 non-nitrogenous foods — viz. fat and carbohydrate. 

 Moleschott gives the following daily diet : — 



Proteid 120 grammes. 



Fat 90 



Carbohydrate 333 



Eanke's diet closely resembles Moleschott's ; it is — 

 Proteid 100 grammes. 



Fat 100 



Carbohydrate 250 „ 



In preparing diet tables, such adequate diets as those just given 

 should be borne in mind. The following dietary (from G. N. 

 Stewart) will be seen to be rather more hberal, but may be taken as 

 fairly typical of what is usually consumed by an adult man in the 

 twenty-four hours, doing an ordinary amount of work. 



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