RATIONAL FEEDING OF MEN 381 



influences the ease or rapidity of digestion to a greater 

 extent than it does the completeness of the process. The 

 carbohydrates are favorably influenced by the action of 

 heat while, in some cases, prolonged heat may make the 

 proteids less digestible. In pasteurized milk, for example, 

 the proteids are slightly less digestible than in pure fresh 

 milk, while in sterilized milk, the digestibility is notice- 

 ably lessened. As in the case of animals, the mechanical 

 condition of a food influences both the ease and the 

 completeness of the process. With persons of sedentary 

 habits, the best results are secured when a small amount 

 of some coarsely granulated food is present. A large 

 amount of such foods, however, is not suitable in the 

 ration of a hard working man because of lack of avail- 

 ability of the nutrients. 



506. Requisites of a Ration. Reasonable combina- 

 tions should be made in forming balanced rations. A 

 number of foods which are slow of digestion or require 

 much intestinal work should not be combined. Neither 

 should a number of foods which are easily digested and 

 leave but little indigestible residue. Two foods which 

 are either laxative or costive should not be combined. 

 After formulating a ration, it should be critically ex- 

 amined to see if it satisfies the following conditions : ( i ) 

 Foods economical and suitable to the work to be per- 

 formed, (2) foods combined so as to secure balanced work 

 of the digestive tract, (3) foods not too laxative or too cos- 

 tive in effect, (4) requisite bulk, (5) sufficient amount of 

 indigestible residue to dilute the waste products in the 

 intestinal tract. 



