150 Heredity and Child Culture 



2. Bread and other cereal foods. Starchy 

 vegetables, as potatoes. 



3. Butter and other wholesome fats. 



4. Green vegetables and fruits. 



5. Simple sweets. 



Calories as Measures of Food Values 



The human body, like the automobile, is run 

 as an internal combustion engine. Energy may 

 be conveniently measured in terms of heat, 

 the calorie or heat unit, being used for this pur- 

 pose. A calorie is the quantity of heat re- 

 quired to raise the temperature of one liter of 

 water one degree centigrade, or very nearly the 

 amount of heat required to raise the tempera- 

 ture of one pound of water from 0° to 4° F. 

 While all nutrients are possible sources of 

 energy, the body should depend upon fats and 

 carbohydrates as energy-producing foods, 

 rather than upon protein, which has tissue build- 

 ing functions not possessed by the other nutri- 

 ents. Moreover, fats are more efficient sources 

 of energy than either protein or carbohydrates. 



