FUEL VALUE 



6l 



physicians, dietitians, nurses, and those having the care of 

 institutional cooking acquaint themselves with the relative 

 fuel values of practically all of the important food substances. 

 The life or death of a patient may be determined by the 

 patient's diet, and the working and earning capacity of a 

 father depends largely upon his prosaic 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 

 vegetables, beans provide the greatest nourishment 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. 26). The food sub- 

 stance is put into a cham- 

 ber A and ignited, and the 

 heat of the burning sub- 

 stance raises the temper- 

 ature of the water in the sur- 

 rounding vessel. If 1000 

 grams of water are in the 

 vessel, and the temperature 

 of the water is raised 2 C, 

 the number of calories pro- 

 duced by the substance 

 would be 2000, and the fuel 

 value would be 2000 calories.* From this the fuel value 

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



* As applied to food, the calorie is greater than that used in the ordinary 

 laboratory work, being the amount of heat necessary to raise the temperature of 

 1000 grams of water iC, rather than I gram IC. 



FIG. 26. The bomb calorimeter from which 

 the fuel value of food can be estimated. 



