CHAPTER IX. 

 FOODS AND COOKING. 



Necessity of Food. Thus far we have been studying 

 processes by which the body's weight is reduced. We 

 have studied the. oxidation in the tissues and the removal 

 of the wastes. Unless the tissues receive a corresponding 

 supply the heat and energy of the body cannot long be 

 maintained. 



Food Defined. All substances that go to make up the 

 tissues or produce energy are foods. Certain substances 

 that do not become part of any tissues, nor in themselves 

 produce energy,- are useful in aiding the processes going 

 on in the body. These may be called accessory foods, e.g. 

 condiments ; some accessory foods, such as coffee, seem to 

 retard the waste of tissues. 



Foods and Foodstuffs. Most of our articles of food 

 consist of two or more different kinds of materials. For 

 instance, milk consists (i) chiefly of water; in this are (2) 

 the substance that makes cheese (casein); (3) cream, from 

 which we get butter (fat) ; (4) sugar, which gives milk a 

 sweet taste; (5) salts, such as common salt, lime salts, 

 etc. These different materials are foodstuffs. We have 

 many kinds of foods, but few foodstuffs, which we find 

 occurring over and over again, in various forms, in the 

 numerous things we eat. 



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