Vol. 6, 1920 
CHEMISTRY: H. C. SHERMAN 
39 
fluences tending toward an over-estimate of the protein requirement should 
also be noted since one or both of them appear to have played a significant 
part in the great majority of experiments which have been made in the past. 
These are: First, the tendency in experiments of this sort to reduce the 
intake of food as a whole, thus creating a deficit in the energy supply, 
which must interfere with the economical use of protein; second, hesita- 
tion, because of past over-estimates of the protein requirement, to reduce 
the amount of protein in the food to a sufficiently low figure to really test 
the minimum on which equilibrium could be established and maintained. 
Every effort has here been made to decide in an objective manner which 
of the past experiments should be included in the average ; yet an element 
of judgment necessarily enters into the selection, especially as some ex- 
periments have been more carefully planned and more rigorously controlled 
than others. 
According to the rigor ousness of the selection, the results may be given 
as follows: First, 109 experiments show a range of 21 to 65 grams and 
an average of 44.4 grams of protein per 70 kg. of body weight per day; 
second, 94 of these experiments show a range of 29 to 56 grams with an 
average of 42.8 grams; third, 76 of the same experiments show a range of 
30 to 50 grams with an average of 40.6 grams. For convenience of com- 
parison, all the results whether the subjects be men or women were here 
reduced to a uniform basis of 70 kg. of body weight — the usual basis for 
the statement of food requirements "per man per day." 
These data reveal no evidence of a sex difference in protein requirement, 
since 67 experiments upon men indicated a requirement of 0.633 gram 
and 42 experiments upon women indicated a requirement of 0.637 gram 
of protein per kilogram of body weight per day. 
In our own more recent experiments, including both men and women, 
although the protein of the food was almost entirely that of the cereal 
grains, the amounts required for maintenance have usually been less 
than the averages above given. Thus, a man of 80 kg. established and 
maintained equilibrium on a daily intake of 37.5 grams of protein, of which 
96% was furnished by ordinary wheat bread. A woman of 55 kg. found 
27 grams of maize protein (from corn meal) almost sufficient, while 30 
grams per day of protein, of which 88% was from corn meal, 10% from 
milk, and 2% from apple, proved more than sufficient. The same sub- 
ject showed essentially the same requirement when oatmeal was substi- 
tuted for corn meal as the chief source of protein, and a second woman 
subject also found fully adequate a diet which furnished not over 0.6 gram 
of protein per kilogram of body weight, about nine-tenths of the protein 
being derived from oatmeal and one-tenth from milk. 
Thus it appears that in the maintenance of healthy men and women 
an intake of not over 35 to 45 grams of protein "per man" of 70 kg. per day 
is sufficient, even when the protein is not selected as of especially high 
