FOODS AND THE THEORY OF DIGESTION 



125 



present in the different materials used as food. This in- 

 formation is supplied by the chemist, who has made exten- 

 sive analyses for this purpose. Results of such analyses 

 are shown in Table I (page 126), which gives the percentage 

 of proteids, fats, carbohydrates, water, and mineral salts 

 in the edible portions of the more common of our foods. 



Food Supply to the Table. The main problem in sup- 

 plying the daily bill of fare is that of securing through the 



POTATO 



CHEESE (FULL CREAM) 



EGG 



WHITE BREAD 



FIG. 6 1 . Relative proportions of different nutrients in well-known foods. 



different food materials the requisite amounts of proteids, 

 carbohydrates, and fats. In this matter a table showing 

 the composition of foods can be used to great advantage. 

 Consulting the table on page 126, it is seen that large per 

 cents of proteids are supplied by lean meat, eggs, cheese, 

 beans, peas, peanuts, and oatmeal, while fat is in excess in 

 fat meat, butter, and nuts (Fig. 61). Carbohydrates are 

 supplied in abundance by potatoes, rice, corn, sugar, and 

 molasses. The different cereals also contain a large per- 

 centage of carbohydrates in the form of starch. 



