Nitrogen Output.
Taken in. 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?
Finally, the writer in summing up his own experience is inclined to say
that while he entered upon this experiment simply with a view to studying
the question from a purely scientific and physiological standpoint,
he has become so deeply impressed with the great gain to the body by
this practice of physiological economy, and his system has become so
accustomed to the new level of nutrition that there is no desire to
return to the more liberal dietetic habits of former years.
* * * * *
Obviously, it is not wise nor safe to draw too broad deductions from a
single individual, nor from a single experiment even though it extends
over a long period of time; consequently, we may turn our attention to
other individuals with presumably different personality and different
habits of life. The writer’s colleague, Dr. Lafayette B. Mendel,
Professor of Physiological Chemistry in the Sheffield Scientific School,
kindly volunteered to become a subject of experiment. With a body-weight
of 76 kilos, 32 years of age, and of strong physique, he commenced to
modify his diet about the middle of October, 1903, diminishing gradually
the amount of proteid food with the results shown in the following
tables, where are given, as in the preceding experiment, the amounts
of nitrogen in the urine, as a measure of the quantity of proteid
metabolized, uric acid, and other factors of interest in this connection.
The collection of data commenced on October 26, 1903. During some weeks
the urine of each day was not analyzed by itself, but an aliquot part
was taken from the 24 hours’ quantity, and at the end of a week the
determinations were made on the mixture, thereby giving the average
daily composition for the period. With Dr. Mendel, as in the writer’s
case, there was no prescribing of food, but perfect freedom of choice.
The appetite was satisfied each day, but with a gradual diminution of
proteid food, especially of meat. Dr. Mendel appeared to accomplish the
desired end best by keeping up a liberal allowance of non-nitrogenous
food, and the total potential energy of the daily diet was not so greatly
diminished as in the writer’s case. In other words, he appeared to need
more food, but succeeded without great effort in reducing the proteid
intake to nearly as low a level as in the preceding experiment. For the
period of three months from January 4 to April 3, 1904, the average daily
excretion of nitrogen amounted to 6.46 grams, which means the metabolism
of 40.37 grams of proteid or albuminous food per day for this quarter of
the year.