NITROGEN BALANCE.—Chittenden.
| Nitrogen Taken in. | Output. | ||||||
|---|---|---|---|---|---|---|---|
| Nitrogen in Urine. | Weight of Fæces (dry). | ||||||
| June | 23 | 6.622 | grams. | 5.26 | grams. | 10.6 | grams. |
| 24 | 6.331 | 5.30 | 0.7 | ||||
| 25 | 4.941 | 4.43 | 14.2 | ||||
| 26 | 5.922 | 4.66 | 11.9 | ||||
| 27 | 5.486 | 4.98 | 15.2 | ||||
| 82.6 | grams contain 6.08% N. | ||||||
| 29.302 | 24.63 | + | 5.022 | grams nitrogen. | |||
| 29.302 | grams nitrogen. | 29.652 | grams nitrogen. | ||||
| Nitrogen balance for five days | = | -0.350 | gram. |
| Nitrogen balance per day | = | -0.070 | gram. |
Average Intake.
| Calories per day | 1549. |
| Nitrogen per day | 5.860 grams. |
Examination of these figures makes quite clear that the body was still in nitrogen equilibrium, or essentially so, the minus balance being so small as to have little significance. The body-weight was still stationary, and yet during this balance period the average daily intake of nitrogen was only 5.86 grams, corresponding to 36.62 grams of proteid or albuminous food. Further, the average daily fuel value of the food was only 1549 calories, a trifle less than in the preceding period. The average daily output of nitrogen through the urine for this period was 4.92 grams, corresponding to the metabolism of 30.7 grams of proteid food. Hence, the results of this period confirm those of the preceding period and make it quite clear that this subject, with a body-weight of 57.5 kilos, can be maintained in body equilibrium, and in nitrogen equilibrium, on a daily diet containing only 5.8 grams of nitrogen and with a fuel value of about 1600 calories. Under these conditions, as in the last balance period, the daily amount of nitrogen metabolized was very small, averaging only 4.92 grams. Comparison of this figure with the accepted standard of 16 grams of nitrogen makes quite clear the extent of the physiological economy which is attainable by the body, and emphasizes also the extent of the unnecessary and worse than useless labor put upon the body by the prevalent dietetic habits of the majority of mankind.
It is of course understood that the low fuel value which sufficed to keep the writer in body equilibrium would not meet the requirements of a more active life, with greater physical labor. The writer has led a very busy life during the year of this experiment, but it has been mental activity rather than physical, although doubtless he has exercised as much as the ordinary professional worker not accustomed to athletic sports. The results of the experiment, however, make it quite clear that a man of the above body-weight, even though he lead a very active life—not involving great physical labor—can maintain his body in equilibrium indefinitely with an intake of 36 to 40 grams of proteid or albuminous food, and with a total fuel value of about 1600 calories. Further, it is to be understood that there is no special form of diet involved in the accomplishment of such a result. Scrutiny of the daily diet, tabulated in the two balance periods, will show the character of the food made use of. Personal likes and dislikes must naturally enter into the choice of any diet, and freedom of choice, freedom to follow the dictates of one’s appetite, with such regulation as comes from the use of reason and intelligence, are all that is necessary to secure the desired end. Physiological economy in nutrition is easily attainable and does not involve the adoption of vegetarianism. It does mean, however, temperance and simplicity in diet, coupled with intelligent regulation, which, however, soon becomes a habit and eventually leads to a moderation in diet which fully satisfies all the cravings of appetite as completely as it suffices to maintain the body in equilibrium and in a general condition of health and vigor.
Taking the data recorded above, we may now calculate the nitrogen requirement of the body per kilo of body-weight. With the body-weight placed at 57 kilos and with an average daily elimination of nitrogen for nearly nine months of 5.699 grams, or practically 5.7 grams, it is evident that the nitrogen metabolized per kilo of body-weight in the present instance was exactly 0.1 gram. If we take the lower figure of 5.40 grams of nitrogen, the average daily excretion from April 13 to June 27, we find the nitrogen requirement to be 0.0947 gram per kilo of body-weight. Translating these figures into terms of proteid or albuminous matter, they mean the utilization or metabolism of 0.625 gram of proteid matter daily per kilo of body-weight, under the conditions of life, activity, and general food consumption prevailing throughout this period of nearly nine months with this particular individual.
Whether we are justified in saying that this figure represents the minimal proteid requirement of this particular individual is perhaps questionable, since the proteid or nitrogen requirement will of necessity vary somewhat with the amount of non-nitrogenous food consumed. Doubtless, the nitrogen metabolism could be reduced still lower by increasing the intake of non-nitrogenous food, but under the above conditions of life, following a plan of living both congenial and satisfactory, one that fully sufficed to keep the body in equilibrium and with the practice of a general physiological economy, we may say that the metabolism of 0.1 gram of nitrogen per kilo of body-weight was quite sufficient to meet all the requirements of the body. Health, strength, mental and physical vigor have been maintained unimpaired, and there is a growing conviction that in many ways there is a distinct improvement in both the physical and mental condition. Greater freedom from fatigue, greater aptitude for work, greater freedom from minor ailments, have gradually become associated in the writer’s mind with this lowered proteid metabolism and general condition of physiological economy. The writer, however, is fully alive to the necessity of caution in the acceptance of one’s feelings as a measure of physical or mental condition, but he has been keenly watchful for any and every sign or symptom during the course of these experiments, and is now strongly of the opinion that there is much good to be gained in the adoption of dietetic habits that accord more closely with the true physiological needs of the body. If a man of 57 kilos body-weight can maintain a condition of equilibrium, with continuance of health, strength, and vigor (to say nothing of possible improvement), with a daily consumption of say 40 grams of proteid food and sufficient non-nitrogenous food to yield 2000 calories, why should he load up his system each day with three times this amount of proteid food, with enough more fat and carbohydrate to yield 3000 plus calories?