DEMANDS OF THE BODY FOR NOURISHMENT. 123 
THE DEMANDS OF THE BODY FOR NOURISHMENT 
AND DIETARY STANDARDS. 
BY W. O. ATWATER. 

HXPERIMENTS WITH MEN IN THE RESPIRATION CALORIMETER. 
One of the objects of experiments with the respiration calo- 
rimeter is to obtain exact information regarding the demands 
of the body for food, with different persons and under different 
conditions of rest and work. Data bearing upon these ques- 
tions are found in all of the experiments. The detailed tables 
elsewhere published* show the total amounts and the composi- 
tion of the food, drink, and excretory products. The figures in 
Table 20 summarize very briefly some of the principal results. 
By ‘‘digested food’’ is understood the total food less the 
intestinal excreta—in other words, the sum of the nutrients 
which are available to the body for the building of tissue and 
yielding of energy, and are hence called ‘‘available nutrients.’’ 
No correction is introduced for metabolic products in the feces, 
since these were derived originally from the food (or body tis- 
sue) and are a necessary accompaniment of undigested material. 
The available energy of the food is the total heat of combustion 
of -the food minus the heat of combustion of the unoxidized 
materials of feces and urine. No further correction for the 
labor of chewing and digesting is included.t 
It is here assumed that the quantity of carbohydrates in the 
body is the same at the beginning as at the end of the expert- 
ment. ‘he gains and losses of body protein and body fat are 
computed from the gains and losses of the nitrogen and car- 
bon.t Accordingly the figures show the average daily amounts 
f 
of available protein and energy supplied by the food and the 

* U.S. Dept. Agr., Office of Experiment Stations, Buls. 44, 63, 69, 109 and 136. 
+ See discussion of this subject in articles on ‘The Terms Digestibility, Availability 
and Fuel Value” and ‘‘ Availability and Fuel Value of Food Materials’ in the Con- 
necticut (Storrs) Station Rept., 1899, pp. 69 and 73. 
t By the method previously described, U. S. Dept. Agr., Office of Experiment Sta- 
tions, Bul. 69, pp. 44, 45. 
