

DEMANDS OF THE BODY FOR NOURISHMENT. 13 Ue 
is also interesting. Such comparisons are made in the follow- 
ing table, which includes also the very ‘exact values obtained 
when the experimental conditions were carefully controlled 
and data were collected regarding the use the body made of 
the food in experiments in which respiration apparatus was 
used. Appended to the table are the commonly accepted diet- 
ary standards. | 
The figures given for fuel value may be computed from either 
the total or the digestible nutrients by use of appropriate fac- 
tors.* The nutritive ratio in each case is calculated by multi- 
plying the weights of the fats by two and one-quarter, adding 
the weight of the carbohydrates and dividing by the weight of 
the protein. The reason for multiplying the fats by two and 
one-quarter is that a gram of fat has two and one-quarter times 
the energy of fuel value of a gram of carbohydrates. Since 
the available energy of a gram of protein is practically equal to 
that of a gram of carbohydrates the nutritive ratio of a given 
food material or a given dietary is practically the ratio of the 
available energy of the protein to that of the carbohydrates and 
fats together. | 
DIETARY STANDARDS. 
Fortunately the subject of the demand of the body for nour- 
ishment is receiving unusual attention of late from physiolo- 
gists, physicians, economists and teachers and it may not be 
unfitting to urge once more the importance of the principles 
enunciated above. | 
The later technical discussion of this subject turns largely 
upon the quantities of protein and energy required for the nor- 
mal nourishment. Several European investigators have pro- 
posed so-called dietary standards, which agree more or less 
closely with each other. Of the European standards the best 
known are those of Voit, which are given in Table 22, together 
with several suggested by myself. 
A dietary standard is in brief, a formula which attempts to 
express the physiological demand for nourishment in terms of 
nutrients, or better in terms of protein and energy. The quan- 
tities of these actually required by a given person vary with 

* tors are as follows: For each gram of total nutrients, protein 4.0, fat 
8.9 Beer aunt varates 4.0 calories. For each gram of digestible nutrients, protein 
a fat 9.4, and carbohydrates 4.1 calories, See Storrs Station Report, 1899, p. 104. ; 
“+See U oS Dept. Agr., Office of Experiment Stations, Bul. 21, page 206, and Farmers’ 
Bulletin 142, p. 34. 
