151 



The body is built up and its wastes repaired by the nutrients. The 

 nutrients also serve as fuel to warm the body and supply it with 

 strength. 



Ways in which the nutrients are used in the body : 



f Form the nitrogenous basis of blood, muscle, sinew, 

 Thealbuminoid I ^^nc, skin, &c. 



ot food j Are chinged into fats and carbo-hydrates. 

 I Are consumed for fuel. 



The fats of j Are stored in the body as fats, 

 food I Are consumed for fuel. 



The carbo- f Are changed into fats, 

 hydrates of food\ Are consumed for fuel. 



r Are transformed into the mineral matters of bone 

 The mineral J ^^^ ^^^er tissues. 



matters of food l . , . • ,, 



Are used m various other ways. 



This is a very instructive table, and it will be well before passing 

 on to consider in more detail what it means. It emphatically tells us 

 in the first place that we cannot exist for any length of time on any one 

 class of nutrients — a fact amply proved by actual experiment No 

 one nutrient is a complete diet. A diet consisting entirely of albumi- 

 noids, or of carbohydrates, or of fats, is an impossible one, though a 

 glance at the table shows that the albuminoids are more universal in their 

 functions that the other two nutrients. We shall learn later on some- 

 what of the proper ratio in which they should be used in order to 

 preserve health. The tissues of the body are continually undergoing 

 disintegration, heat is being dissipated and muscular and intellectual 

 energy constantly expended. Let us examine for a moment the different 

 classes of food as to their power to supply these wants. 



We have already said that animal foods — meats of all kinds and 

 fish — are principally nitrogenous. The albuminoids they contain are 

 often called flesh formers, because such go to form in the body the 

 muscle and the blood. They also possess more or less fat, which may 

 be laid up or converted into adipose tissue or used up in the production 

 of heat. 



The vegetable foods consist largely of the carbo-hydrates, and 



