white of egg and lean meat are examples. So important are 

 these substances that many authorities have divided foods 

 into two main groups. 



(1) Body-builders and repairers. (Protein, chiefly con- 

 tained in meat, eggs, milk, peas, beans, kernels, grain, etc.) 



(2) Energy-producers, yielding heat and work. (Fats, 

 and oils [hydrocarbons] with sugar and starch [carbohy- 

 drates].) 



A definite proportion of protein food (10-15 per cent.) is 

 an absolute essential of the diet, and people who fail to get 

 a sufficient amount of such food quickly show the result in 

 diminished vigor. Pellagra, a serious disease which occurs 

 particularly among the poor population of our southern 

 states, is closely connected with a diet poor in protein, and 

 can be cured by the substitution of one rich in meat, eggs and 

 milk. 



The table below, showing the classification of certain com- 

 mon foodstuffs according to their richness in proteins and 

 fats, is taken from the excellent handbook on "How to Live/' 

 by Prof. Irving Fisher and Dr. E. L. Fisk. Foods low in 

 both proteins and fats are composed chiefly of carbohy- 

 drates (sugar and starches). 



Common Foods Classified 

 Poor in Fat Rich in Fat 





White of eggs 





Very high 



Codfish 





in 



Lean beef 





Protein 



Chicken 

 Veal 







Shellfish 



Most fish 



High in 



Skim milk 



Most meats 



Protein 



Lentils 



Most fowl 





Peas 



Whole egg 





Beans 



Cheese 



