FOODS AND NUTRITION 



401 



For the person who has a general idea of the amount 

 and proportion of the food substances required for 

 his daily use it will be quite easy to select a good mixed 

 diet from the table given on page 403. A mixed diet 

 is quite necessary, since milk is the only food that 

 contains protein, fat, and carbohydrate in a proportion 

 approximating that of protoplasm (Figure 355). Milk 

 can be used as the sole food of children for this reason. 

 By a careful selection of foods it is possible to obtain the 



FIG. 356. Nutritive Values of Bread, Beef, and Eggs. 



Fats, black ; carbohydrates, horizontal lines ; proteins, vertical lines ; other 



parts, water. 



proper proportion of essentials with a minimum of waste 

 products (Figures 356, 357). A vegetable diet contains 

 a great deal of waste materials and for this reason is less 

 healthy than a mixed diet containing meats. The vege- 

 tarian is correct in his contention that vegetables contain 

 everything necessary to life, but it is quite easy to select 

 foods which contain these same essentials and which re- 

 quire much less work of the digestive organs in their 

 assimilation. Some animals live on purely vegetable 



