68 



FOOD 



Fuel value. By fuel value is meant the capacity foods 

 have for yielding heat and energy to the body. The fuel 

 value of the foods we eat is so important a factor that phy- 

 sicians, nurses, and dietitians acquaint themselves with the fuel 

 values of the important food substances. The life or death of a 

 patient may be determined by the patient's diet, and the work- 

 ing and earning power of a father depends largely upon his 

 three meals. An ounce of fat, whether it is the fat of meat or 

 the fat of olive oil, or the fat of any other food, 

 produces in the body two and a quarter times as 

 much heat as an ounce of starch. Of the vege- 

 tables, beans provide the greatest heat and energy 

 at the least cost, and to a large extent may be 

 substituted for meat. It is not uncommon to find 

 an outdoor laborer consuming one pound of beans 

 per day, and taking meat 

 only on "high days and 

 holidays." 



The fuel value of a food is 

 determined by means of the 

 bomb calorimeter (Fig. 35). 

 The food substance is put 

 into a chamber A and ig- 

 nited, and the heat of the 

 burning substance raises the 



-----A 



temperature of the water in FIG. 35. Diagram of a bomb calorimeter 



the surrounding vessel. If ^f ate w d hich the value of food can be esti ' 

 2 kilograms of water are in 



the vessel, and the temperature of the water is raised 50 Q, 

 the number of Calories produced by the substance is 100, and 

 the fuel value of it is 100 Calories. From this the fuel value 

 of one pound or one quart of the substance can be deter- 

 mined, and the food substance furnishes the body with that 



