Third Nitrogen Balance.
The last of March, a third nitrogen balance was tried on a slightly lowered nitrogen intake and with a slight increase in the fuel value of the daily food. In this period of five days, March 28 to April 1, the nitrogen taken in per day averaged 8.62 grams, or nearly one gram per day less than in the preceding period. The fuel value of the food averaged 2840 calories per day, or about 300 calories more than in the preceding period.
The daily diet, with its content of nitrogen, etc., is detailed for each day under Oakman. Any deviation from this diet in the cases of the other men is indicated on the accompanying balance-sheets.
The results obtained in this balance period indicate that the lowest level had been practically reached, at least under the conditions of body-weight, food, and work prevailing. Cohn, Fritz, and Broyles showed a distinct positive balance. Steltz and Loewenthal were practically in equilibrium, the deviation being within the limits of error. The remaining six men showed a minus balance, although in no case was it very marked.
It is interesting to note in this connection that the average daily output of nitrogen through the urine for this five days’ period (Oakman’s case) amounted to 7.04 grams, being 0.2 gram less per day than in the preceding period. This figure for nitrogen in the urine means the metabolism daily of 44 grams of proteid.
Undoubtedly, the rate of proteid metabolism for these men could have been lowered considerably beyond the present level by increasing largely the intake of carbohydrates and fats, but it has been the intent throughout all of these experiments to learn the minimal proteid requirement under conditions precluding the use of any excess of non-nitrogenous foods; also, to study the effect of a general physiological economy in nutrition, with a view to ascertaining the real necessities of the body for both proteid and non-proteid foods with maintenance of bodily strength and vigor. Hence, we may again emphasize the fact that the low proteid metabolism maintained by all these men throughout the period of the experiment, with establishment of nitrogenous equilibrium on a consumption of proteid or albuminous food averaging one-half the amount ordinarily specified as the daily requirement of the healthy man, has been accomplished with even less total food—fats and carbohydrates—than the ordinary standards call for, i. e., considerably less than 3000 calories per day in fuel value.
OAKMAN.
Monday, March 28, 1904.
Breakfast.—Fried rice 150 grams, syrup 75 grams, baked potato 250 grams, butter 20 grams, one cup coffee 350 grams.