340 HOW DOES MAN DETERMINE THE VALUE OF FOOD? 



meat is another man's (10), so we should learn what we can 



(11). Acidosis may be combated by a diet in which an excess 



of (12) and (13) is present. 



PROBLEM IV. WHAT IS THE BEST PROPORTION OF 

 NUTRIENTS IN OUR DAILY DIET? 



The nutritive ratio. Inasmuch as all living substance contains 

 nitrogen, it is evident that protein food must form a part of the 

 diet; but protein alone is not a safe choice. If more protein is 

 eaten than the body requires, the liver and kidneys have to 

 work overtime to get rid of the excess of protein, which forms 

 a poisonous waste harmful to the body. We must take foods 

 that will give us, as nearly as possible, the proportion of the 

 different chemical elements as they are contained in protoplasm, 

 as well as an amount necessary to supply energy to the body. It 

 has been found, as a result of studies by Atwater and others, 

 that a man who does moderate muscular work requires nearly 

 one quarter of a pound of protein, the same amount of fat, and 

 a little less than one pound of carbohydrate to provide for the 

 growth, waste, and repair of the body and the energy used up 

 in one day. The proportion of protein in the diet is called the 

 nutritive ratio. 



The protein requirement varies with the age and size of a person, 

 but not with the activity. For the child, from 12 to 15 per cent 

 of the total Calories should be protein. Protein is necessary for 

 the building and the repair of the body. Therefore larger amounts 

 are needed during growth. The child requiring 2000 Calories 

 needs from 240 to 300 Calories of protein. Whereas the adult, 

 who has ceased growing, needs but 10 per cent of his total in 

 protein. Therefore with an energy requirement of 2500 he would 

 need about 250 protein Calories. Activity has never been shown 

 to break down the body cells any more than the use of the brain 

 destroys brain cells. Therefore protein does not need to be in- 

 creased because one is doing muscular work. Milk, meat, and 

 eggs are just as essential for the school teacher as for the man who 

 is doing severe muscular work. 



