I 3 6 ° The Cornell Reading-Courses 



The unit of measure far determining the energy requirement of tlie body. — 

 Just as there must be some unit of measure for weight, for distance, 

 for temperature, for cubical contents, for money, so there must be 

 some unit of measure for energy or heat. The pound, the yard, the 

 square inch, the degree, the dollar, are so familiar to us that we 

 never question what they mean or how they were obtained. We have 

 always been accustomed to seeing solids weighed and distances 

 measured. We have learned to translate values in terms of dollars 

 and cents. Our experience even gives us some fairly accurate idea of what 

 is meant when we say that the thermometer stands at 32° or ioo° F. 

 The unit of measure for energy, or heat, which is called a "calorie." has 

 not been in the past a part of our education; but it is to be important 

 in the future if we are to provide best conditions for human welfare. 



In any large factory where many engines are in use and furnaces must 

 be kept going night and day, the energy value of fuel consumed is of great 

 importance. Just as the grocer must know how many pounds or bushels 

 or tons are being delivered to him, so the manufacturer must know how 

 much energy — that is, how many heat units, or calories — the fuel that 

 he is buying is capable of giving him. He, like the grocer, cannot afford 

 to pay for short measure. 



Daily food requirement. — The human body, like the machine, is a 

 spender of energy. We must learn what amount of energy — which we 

 measure by calories, or heat units — the body spends every day under 

 different conditions of age and activity; and we must determine the amount 

 of energy that the various common foods are capable of giving to the body, 

 and then compare the various foods in terms of the calories that they are 

 capable of yielding. We must find out how much building material, in 

 the form of protein, the body needs each day and how much and at what 

 cost our various foods can supply protein. We must find out how much 

 lime, iron, phosphorus, magnesium, and potassium are needed, and how the 

 common foods compare as sources of those substances. Finally, we must stop 

 and consider all the data accumulated and learn whether the energy, protein, 

 calcium, and other material furnished by one food, even at a lower cost than 

 by another, are of as good a type and as available to the body as those 

 supplied by that other. Then, and only then, have we a real basis for 

 comparing the cost of foods. Then only do we begin to develop a philosophy 

 of the right and economical nutrition of those for whom we must care. 



Table for esti \g food requirements. — The following table, like any 



table of the kind, is only a guide, or indication, as to the food requirements 

 of the bodv as these are understood to-dav. While it cannot be followed 



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inflexibly, it should at least serve a useful purpose in giving an idea of the 

 amounts of some of the typical food substances needed, and will form a 

 basis for comparing the values of various foods in supplying those needs. 



