RATIONAL FEEDING OF MEN 



383 



trients in approximately the amounts given. By means 

 of a careful study of the dietary, it is possible to reduce 

 the cost of food without impairing its nutritive value, 

 and in many cases, as the cost is decreased, the nutritive 

 value is increased. 



508. Chemical Changes in the Cooking of Foods. The 

 chemical changes which take place in cooking are brought 

 about by the joint action of heat, water and ferments and 

 occasionally by the use of chemicals. The various com- 

 pounds of which foods are composed, namely, carbohy- 

 drates, proteids and fats, are all susceptible to the action of 

 these agencies and the chemical changes which they un- 

 dergo are briefly discussed in Chapters XXIII and XXIV, 

 treating of the composition of the nitrogenous and non- 

 nitrogenous compounds. Some of the changes are phys- 

 ical rather than chemical in character. All of the differ- 

 ent nutrients of foods are influenced by the action of heat. 



FIBER 



Fig. loi. Comparative composition of raw and baked beans. 



Starch, in the presence of water and heat, undergoes 

 partial hydration, so that the material is in a condition 



