102 ELEMENTARY BIOLOGY 



A comparison of the food requirements of men and women at 

 different periods of life, and according to worlc done, is given in the 

 following table, in which loo represents the requirements of a man 

 per day (cf. table on page loo) : 



r> -J r ^ 77 • For Men For Women 



Period of full vigor 



Engaged in moderate work loo 80 



Engaged in hard work . . . .' . . 120 100 



Engaged in light work (sedentary J ... 80 70 



In declining vigor 



In old age 90 90 



In extreme old age 70-80 70-80 



From the discussion and the tables given above, one should be 

 able to calculate the requirements of different people in the way of 

 proteins, fats, and carbohydrates, and to translate these requirements 

 into the actual food articles that make up our meals, so as to secure 

 a balanced diet. 



One other thing needs to be considered in making up a 

 plan for a dietary, and that is the matter of climate and seasons. 

 We have learned from our reading about different races of 

 men that the natives of tropical countries eat very little meat, 

 whereas the natives of cold countries eat very little fruit but a 

 great deal of fat. We can understand why the Eskimos eat no 

 fruit : there is no fruit to be had where they live. But the in- 

 habitants of the tropics can get almost any kind of food they 

 might wish. The fact is, however, that in a cold region one 

 must provide for a larger supply of heat than in a hot region. 

 As fat yields the largest amount of energy in proportion to 

 weight, it is especially desirable in the diet when energy is to 

 be increased, rather than building material or bulk. So we 

 may increase our fuel foods in the winter and reduce them 

 in the summer. 



137. Balanced diet. Many people have supposed that there 

 must be an ideal food, some one material that would satisfy 

 all the needs of the body ; if this were found, we should save 



