An example of the first method of formulating dietaries is that of Professor Atwater's respiration calorimeter, sometimes called "the man in a box," described in one of the government pamphlets. A small room was constructed in the laboratory with flues arranged to bring in fresh air and to carry off the products of respiration. Each of these flues was arranged so that the temperature and composition of the air entering and going out might be determined. A man lived in this room for several days at a time, his food being given to him by means of slides in a double wall. A sample of each food given was analyzed and a determination of the number of calories yielded by it made by means of the bomb calorimeter. All food taken was carefully weighed, and the excreta of the body were analyzed so that an accurate estimate could be made of the total income and outgo of the body. See illustration on page 32.
Many statistical dietaries have been taken, some of the most valuable being those of the German army. Experiments have been made there as to the effect of the addition of certain articles of food to the diet, and the conclusions have been of much value. Similar dietary studies have been made at many schools and universities.
From a careful comparison of dietaries made up in these two ways certain standards have been determined upon. The American standards vary in some important points, notably in the amount of fat used, from those of Europe. Some of these dietaries are given here.
Man at moderate work (German).............
Man at hard work (German)..................
Man with moderate exercise (English).......
Active laborer (English)......................
Woman with light exercise (American)......
Man with light exercise (American)........
Man at moderate work (American)...........
Man at hard work (American).............
There are twenty-eight and thirty-four hundredths grams (28.34) in one ounce. A man at moderate work requires, therefore, according to the American standard, about four and one-half ounces of proteid, four and one-half ounces of fat, and nearly a pound of carbohydrate daily.