332 THE FOODS WE EAT 



15 per cent of our total Calories should come from proteins. 

 One widely used standard says a ratio of 1 Calorie from 

 proteins, 3 from fats, and 6 from carbohydrates is about 

 right, although others believe that a ratio containing even 

 less protein is desirable. Later we will find that not all 

 proteins are equally valuable for building body cells, so 

 the kinds of proteins as well as the amounts used are im- 

 portant in making up a diet. Young people need rela- 

 tively more protein in the diet than do older persons, 

 because they lead more active lives and are growing. For 

 such, proteins should come largely from eggs, milk, lean 

 meats, and whole-grained cereals. 



SELF-TESTING EXERCISE 



Select from the following list those words which best fill the blank spaces 

 in the sentences below and arrange the words in proper numerical order. 

 A word may be used more than once. 



differ 



proteins 



weight 



5 per cent 



loses 



eight 



active 



less 



In the human machine just as in the automobile the (1) 



which makes both go comes from the (2) of fuel. In the 



human machine the food is (3) in the (4) of the body, 



thus releasing the (5) where it is used. The unit of heat 



used in measuring energy released from foods is called the (6) 



It is the amount of heat necessary to raise the temperature of a 



(7) of water (8) degrees (9) (10) give about 



twice as much energy as do (11) or (12) The (13) 



requirements of the body (14) , depending upon age, sex, 



season of the year, and kind of work done by the individual. A 



rapidly growing boy or girl needs (15) food than does an old 



man, because the former is making new (16) and thus gaining 



in (17) A person needs more (18) in winter than in 



summer, because the body (19) heat more rapidly then and 



