CHAPTER V 



FOOD 



55. The Body as a Machine. Wholesome food and fresh 

 air are necessary for a healthy body. Many housewives, 

 through ignorance, supply to their hard-working husbands 

 and their growing sons and daughters food which satisfies 

 the appetite, but which does not give to the body the elements 

 needed for daily work and growth. Some foods, such as 

 lettuce, cucumbers, and watermelons, make proper and satis- 

 factory changes in diet, but are not strength giving. Other 

 foods, like peas and beans, not only satisfy the appetite, 

 but supply to the body abundant nourishment. Many im- 

 migrants live cheaply and well with beans and bread as 

 their main diet. 



It is of vital importance that the relative value of different 

 foods as heat producers be known definitely ; and jftst as the 

 yard measures length and the pound measures weight the 

 calorie is used to measure the amount of heat which a food is 

 capable of furnishing to the body. Our bodies are human 

 machines, and, like all other machines, require fuel for their 

 maintenance. The fuel supplied to an engine is not all avail- 

 able for pulling the cars ; a large portion of the fuel is lost in 

 smoke, and another portion is wasted as ashes. So it is with 

 the fuel that runs the body. The food we eat is not all avail- 

 able for nourishment, much of it being as useless to us as are 

 smoke and ashes to an engine. The best foods are those 

 which do the most for us with the least possible waste. 



56. Fuel Value. By fuel value is meant the capacity foods 

 have for yielding heat to the body. The fuel value of 

 the foods we eat daily is so important a factor in life that 



60 



