CHAPTER VI
FURTHER EXPERIMENTS AND OBSERVATIONS BEARING ON TRUE FOOD REQUIREMENTS
Topics: Dietary experiments with a detail of soldiers from the United States army. General character of the army ration. Samples of the daily dietary adopted. Rate of nitrogen metabolism attained. Effect on body-weight. Nitrogen balance with lowered proteid consumption. Influence of low proteid on muscular strength of soldiers and athletes. Effect on fatigue. Effect on physical endurance. Fisher’s experiments on endurance. Dangers of underfeeding. Dietary observations on fruitarians. Observations on Japanese. Recent dietary changes in Japanese army and navy. Observations of Dr. Hunt on resistance of low proteid animals to poisons. Conclusions.
General acceptance of a new theory, or a new point of view, can be expected only when there is an adequate amount of scientific evidence on which the theory can safely rest. Facts cannot be ignored, and the larger the amount of supporting evidence the more certain becomes the general truth of the theory to which it points. Corroborative evidence, therefore, is always desirable, and he who would open up a new point of view must be zealous in accumulating facts to uphold his position. Critics there are without number who are ever ready to pick flaws in an argument or overturn a theory, especially if the one or the other stands opposed to their own point of view. This, however, is highly advantageous for the advance of sound knowledge, since it necessarily prompts the advocate to search in all directions for added data, by which he can build a bulwark of fact sufficient to defy just criticism. Further, the true scientific spirit demands persistent and painstaking effort in the search after truth, that error and misconception may be avoided.
In harmony with these ideas, our attempt to ascertain the real needs of the body for proteid food led us to enlarge our evidence by a series of experiments with still another body of men, i. e., a detail of soldiers from the United States army.[61] This was a somewhat more difficult and ambitious undertaking, since the number of subjects involved was larger, and because with this group of men we could not expect quite that high degree of intelligent co-operation afforded by the preceding subjects. Still, this very fact was in a sense an added inducement, since it offered the opportunity of experimenting with a body of men who naturally would not take kindly to anything that looked like deprivation, and whose continued co-operation could be expected only by satisfying their natural demands for food. If this could be accomplished by an intelligent prescription in their daily diet, and the experiment brought to a successful conclusion, with maintenance of body-weight, nitrogen equilibrium, health, strength, and general vigor; with an intake of proteid food essentially equal to that adopted by the preceding subjects, corroborative evidence of the highest value would be obtained.
The detail was composed of a detachment of twenty men from the Hospital Corps of the army, under the command of a first lieutenant and assistant surgeon. They were located in a convenient house near to the laboratory, where they lived during their six months’ stay in New Haven, under military discipline, and subject to the constant surveillance of the commanding officer and the non-commissioned officers. Having well-trained cooks and assistants, with all necessary facilities for preparing and serving their food, with members of the laboratory staff to superintend the weighing of the food as it was placed before the men, and with intelligent clerks to attend to the many details connected with such an undertaking, a somewhat unique physiological experiment was started. Thirteen members of the detachment really took part in the experiment as subjects, and they represented a great variety of types: of different ages, nationalities, temperaments, and degrees of intelligence. They were men accustomed to living an active life under varying conditions, and they naturally had great liking for the pleasures of eating. Further, it should be remembered that, although the men had volunteered for the experiment, they had no personal interest whatever in the principles involved, and it could not be expected that they would willingly incommode themselves, or suffer any great amount of personal inconvenience. Again, there were necessary restrictions placed upon their movements, when relieved from duty, which constituted something of a hardship in the minds of many of the men and added to the irksomeness and monotony of their daily life. Regularity of life was insisted upon, and this was a condition which brought to some of the men a new experience. These facts are mentioned because their recital will help to make clear that, from the standpoint of the men, there were certain depressing influences connected with the experiment which would add to any personal discomfort caused by restriction of diet.
The ordinary army ration to which these men were accustomed was rich in proteid, especially in meat, and during the first few days they were allowed to follow their usual dietary habits, in order that data might be obtained bearing on their average food consumption. The details of one day’s food intake will suffice to show the average character and amount of the food eaten per man:
Breakfast.—Beefsteak 222 grams, gravy 68 grams, fried potatoes 234 grams, onions 34 grams, bread 144 grams, coffee 679 grams, sugar 18 grams.
Dinner.—Beef 171 grams, boiled potatoes 350 grams, onions 55 grams, bread 234 grams, coffee 916 grams, sugar 27 grams.
Supper.—Corned beef 195 grams, potatoes 170 grams, onions 21 grams, bread 158 grams, fruit jelly 107 grams, coffee 450 grams, sugar 21 grams.
It is not necessary to comment upon the large proportion of proteid matter in the day’s ration; the three large portions of meat testify clearly enough to that fact, while the three equally large volumes of coffee indicate a natural disposition toward generous consumption of anything available. Habit, reinforced by inclination, had evidently placed these men on a high plane of food consumption.
For a period of six months, a daily dietary was prescribed for the subjects; the food for each meal and for every man being of known composition, each article being carefully weighed, while the content of nitrogen in the day’s ration was so graded as to bring about a gradual reduction in the amount of proteid ingested. The rate of proteid katabolism was likewise determined each day by careful estimation of the excreted nitrogen, balance experiments being made from time to time in order to ascertain if the men were in a condition of nitrogen equilibrium. Finally, it should be mentioned that the subjects lived a fairly active life, having each day a certain amount of prescribed exercise in the university gymnasium, in addition to the regular drill and other duties associated with their usual work.
Photograph of the soldiers taken at the close of the experiment
Photograph of the soldiers taken at the close of the experiment
As just stated, the amount of proteid food was gradually reduced, three weeks being taken to bring the amount down to a level somewhat commensurate with the estimated needs of the body. This naturally resulted in diminishing largely the intake of meat, though by no means entirely excluding it. Effort was constantly made to introduce as much variety as was possible with simple foods, though the main problem with this group of men was to keep the volume of the food up to such a point as would dispel any notion that they were not having enough to eat. A second problem, which at first threatened trouble, was the fear of the men, as they saw the proportion of meat gradually drop off, that they were destined to lose their strength; but fortunately, they very soon began to realize that their fears in this direction were groundless, and a little later their personal experience opened their eyes to possible advantages which quickly drove away all further thought of danger, and made them quite content to continue the experiment. We may introduce here a few samples of the daily food given to the men after they had reached their lower level of proteid intake:
January 15.
Breakfast.—Wheat griddle cakes 200 grams, syrup 50 grams, one cup coffee[62] 350 grams.
Dinner.—Codfish balls (4 parts potato, 1 part fish, fried in pork fat) 150 grams, stewed tomato 200 grams, bread 75 grams, one cup coffee 350 grams, apple pie 95 grams.
Supper.—Apple fritters 200 grams, stewed prunes 125 grams, bread 50 grams, butter 15 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 8.560 grams.
January 16.
Breakfast.—Soft oatmeal 150 grams, milk 100 grams, sugar 30 grams, bread 30 grams, butter 10 grams, one cup coffee 350 grams.
Dinner.—Baked macaroni with a little cheese 200 grams, stewed tomato 200 grams, bread 50 grams, tapioca-peach pudding 150 grams, one cup coffee 350 grams.
Supper.—Fried bacon 20 grams, French fried potato 100 grams, bread 75 grams, jam 75 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 7.282 grams.
March 1.
Breakfast.—Fried rice 150 grams, syrup 50 grams, baked potato 150 grams, butter 10 grams, one cup coffee 350 grams.
Dinner.—Thick pea soup 250 grams, boiled onions 150 grams, boiled sweet potato 150 grams, bread 75 grams, butter 20 grams, one cup coffee 350 grams.
Supper.—Celery-lettuce-apple salad 120 grams, crackers 32 grams, American cheese 20 grams, potato chips 79 grams, one cup tea 350 grams, rice custard 100 grams.
Total nitrogen content of the day’s food = 7.825 grams.
March 3.
Breakfast.—Boiled hominy 175 grams, milk 125 grams, sugar 25 grams, baked potato 150 grams, butter 10 grams, one cup coffee 350 grams.
Dinner.—Hamburg steak with much bread, fat, and onions 150 grams, boiled potato 250 grams, bread 75 grams, butter 10 grams, one cup coffee 350 grams.
Supper.—Tapioca-peach pudding 250 grams, bread 75 grams, butter 20 grams, jam 75 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 8.750 grams.
March 6.
Breakfast.—Sliced banana 100 grams, fried Indian meal 150 grams, syrup 50 grams, baked potato 150 grams, butter 10 grams, one cup coffee 350 grams.
Dinner.—Corned beef 50 grams, boiled cabbage 200 grams, mashed potato 250 grams, bread 75 grams, fried rice 100 grams, jam 75 grams, one cup coffee 350 grams.
Supper.—Crackers 32 grams, butter 10 grams, sardine 14 grams, sponge cake 150 grams, apple sauce 150 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 10.265 grams.
March 30.
Breakfast.—Sliced banana 250 grams, fried hominy 150 grams, butter 10 grams, syrup 75 grams, one cup coffee 350 grams.
Dinner.—Codfish balls 125 grams, mashed potato 250 grams, stewed tomato 200 grams, bread 35 grams, apple sauce 200 grams, one cup coffee 350 grams.
Supper.—Chopped fresh cabbage with salt, pepper, and vinegar 75 grams, bread 50 grams, butter 20 grams, fried sweet potato 250 grams, cranberry sauce 200 grams, sponge cake 50 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 9.356 grams.
March 31.
Breakfast.—Fried Indian meal 100 grams, syrup 75 grams, baked potato 250 grams, butter 20 grams, one cup coffee 350 grams.
Dinner.—Tomato soup, thick, with potatoes and onions boiled in, 300 grams, scrambled egg 50 grams, mashed potato 200 grams, bread 50 grams, butter 10 grams, one cup coffee 350 grams.
Supper.—Fried bacon 20 grams, boiled potato 200 grams, butter 10 grams, bread pudding 150 grams, sliced banana 200 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 8.420 grams.
April 1.
Breakfast.—Fried hominy 150 grams, syrup 75 grams, baked potato 200 grams, butter 20 grams, one cup coffee 350 grams.
Dinner.—Baked spaghetti 200 grams, mashed potato 250 grams, boiled turnip 150 grams, bread 35 grams, butter 10 grams, apple sauce 200 grams, one cup coffee 350 grams.
Supper.—Fried bacon 25 grams, fried sweet potato 200 grams, bread 35 grams, butter 20 grams, jam 100 grams, apple-tapioca pudding 300 grams, one cup tea 350 grams.
Total nitrogen content of the day’s food = 7.342 grams.
These dietaries are fair samples of the daily food given the men during the last five months of the experiment. If we place the intake of nitrogen at 8.5 grams per day, or even 9 grams daily, it would mean at the most an average daily consumption of 56 grams of proteid; viz., about one-third the amount they were accustomed to take under their ordinary modes of life. Of greater interest, however, is the rate of proteid katabolism shown by these men under the above conditions of diet, during the five months’ period. The average daily output of metabolized nitrogen for each man ranged from 7.03 grams—the lowest—to 8.91 grams—the highest. An excretion of 7.03 grams of nitrogen per day means a katabolism, or breaking down, of 43.9 grams of proteid matter; while the excretion of 8.91 grams of nitrogen corresponds to a katabolism of 55.6 grams of proteid. The grand average, i. e., the average daily output of nitrogen of all the men for the five months’ period amounted to 7.8 grams per man, corresponding to an average daily katabolism of 48.75 grams of proteid. The heaviest man of the group had a body-weight of 74 kilograms, while his average daily output of metabolized nitrogen amounted to 7.84 grams. This corresponds to 0.106 gram of metabolized nitrogen per kilo of body-weight; a figure which agrees quite closely with the lowest figures obtained with the preceding subjects when calculated to the same unit of weight. Many of the men, however, metabolized considerably more nitrogen or proteid in proportion to their body-weight, due in a measure at least to the fact that they were being fed more liberally with proteid food than was really necessary for the needs of the body. In this group, we have a body of men doing a reasonable amount of physical work, who lived without discomfort for five consecutive months on a daily consumption of proteid food not much, if any, greater than one-third the amount called for by common usage, and the average fuel value of which certainly did not exceed 3000 calories per day. Indeed, so far as could be determined on the basis of chemical composition, the heat value of the food was quite a little less than this figure would imply.
If the relatively small amount of proteid food made use of in this trial was inadequate for the real necessities of the body, some indication of it would be expected to reveal itself, with at least some of the men, by the end of the period. One criticism frequently made is that the subject draws in some measure upon his store of body material. Should this be the case, it is evident that body-weight—in such a long experiment as this—will gradually but surely diminish. Further, the subject will show a minus nitrogen balance, i. e., there will be a constant tendency for the body to give off more nitrogen than it takes in. As bearing on the first point, the following table showing the body-weights of the men at the commencement of the experiment in October, and at the close of the experiment in April will be of interest:
TABLE OF BODY-WEIGHTS
| October, 1903 | April, 1904 | |
|---|---|---|
| kilos | kilos | |
| Steltz | 52.3 | 53.0 |
| Zooman | 54.0 | 55.0 |
| Coffman | 59.1 | 58.0 |
| Morris | 59.2 | 59.0 |
| Broyles | 59.4 | 61.0 |
| Loewenthal | 60.1 | 59.0 |
| Sliney | 61.3 | 60.6 |
| Cohn | 65.0 | 62.6 |
| Oakman | 66.7 | 62.1 |
| Henderson | 71.3 | 71.0 |
| Fritz | 76.0 | 72.6 |
| Bates | 72.7 | 64.3 (Feb.) |
| Davis | 59.3 | 57.2 (Jan.) |
As is readily seen, five of the men practically retained their weight or made a slight gain. Of the others, Coffman, Loewenthal, Sliney, and Cohn lost somewhat, but the amount was very small. Further, the loss occurred during the first few weeks of the experiment, after which their weight remained practically stationary. Fritz and Oakman lost weight somewhat more noticeably, but this loss likewise occurred during the earlier part of the trial. The accompanying photographs of Fritz, taken at the close of the experiment, show plainly that such loss of weight as he suffered did not detract from the appearance of his well-developed musculature. Certainly, the photographs do not show any signs of nitrogen starvation, or suggest the lack of any kind of food.
Of all the men, Bates was the only one who underwent any great loss of weight. He, however, was quite stout, and the work in the gymnasium, reinforced by the change in diet, brought about what was for him a very desirable loss of body-weight. It is evident, therefore, that there was no marked or prolonged loss of body-weight as a result of the continued use of the low proteid diet. Regarding the second point, viz., nitrogen equilibrium, the following illustrations will suffice to indicate the relationship existing between the income and outgo of nitrogen. A balance experiment with each of the men, lasting seven days, February 29 to March 6, is here shown, the figures given being the daily averages for the period:
| Nitrogen of Food. | Nitrogen of Urine. | Nitrogen of Excrement. | Nitrogen Balance. | |
|---|---|---|---|---|
| grams | grams | grams | grams | |
| Oakman | 9.52 | 7.24 | 1.76 | +0.52 |
| Henderson | 9.40 | 7.90 | 1.00 | +0.50 |
| Morris | 9.49 | 6.05 | 2.30 | +1.14 |
| Coffman | 9.53 | 7.92 | 1.47 | +0.14 |
| Steltz | 9.62 | 7.16 | 1.95 | +0.51 |
| Loewenthal | 9.64 | 7.00 | 1.71 | +0.95 |
| Cohn | 9.27 | 7.63 | 1.41 | +0.23 |
| Zooman | 9.49 | 7.13 | 1.76 | +0.60 |
| Sliney | 9.52 | 8.08 | 1.92 | –0.48 |
| Broyles | 9.43 | 7.01 | 1.19 | +1.23 |
| Fritz | 9.37 | 6.36 | 1.81 | +1.20 |
FRITZ
At the close of the experiment
With one exception, all of the men were plainly having more proteid food than was necessary to maintain the body in nitrogen equilibrium, the plus nitrogen balance in most cases being fairly large. It is only necessary to remember that a gain to the body of 1 gram of nitrogen means a laying by of 6.25 grams of proteid, and with such a gain per day it is apparent that the men were really being supplied with an excess of proteid food. This view is supported by the fact that a later balance experiment, when considerably less proteid food was being given, still showed many of the men in a condition of plus balance, or with a minus balance so small as to indicate essentially nitrogen equilibrium. The following figures, being daily averages of a balance period about the first of April, may be offered in evidence:
| Nitrogen of Food. | Nitrogen of Urine. | Nitrogen of Excrement. | Nitrogen Balance. | |
|---|---|---|---|---|
| grams | grams | grams | grams | |
| Broyles | 8.66 | 6.63 | 1.87 | +0.16 |
| Fritz | 8.13 | 5.77 | 1.63 | +0.73 |
| Loewenthal | 8.51 | 6.51 | 2.02 | –0.02 |
| Steltz | 8.32 | 6.50 | 1.88 | –0.06 |
| Cohn | 8.29 | 6.25 | 1.55 | +0.49 |
| Morris | 8.45 | 6.49 | 2.27 | –0.31 |
| Oakman | 8.62 | 7.04 | 1.87 | –0.29 |
A daily intake of 8.5 grams of nitrogen means the consumption of 53 grams of proteid. Under these conditions of diet, the average daily amount of nitrogen metabolized was 6.45 grams, corresponding to 40.3 grams of proteid. The men were practically in a condition of nitrogen equilibrium, so that we are apparently justified in the general statement that the simple dietary followed with these men during the six months’ experiment, and which was accompanied by an average daily metabolism, after the first three weeks, of 7.8 grams of nitrogen, was certainly sufficient to maintain both body-weight and nitrogen equilibrium. Lastly, emphasis may be laid upon the fact that these values for nitrogen do not necessarily represent the minimal proteid requirement of the human body, since it is a well-established physiological principle that by increase of non-nitrogenous food the rate of proteid katabolism can always be further diminished; a principle which is plainly in harmony with the view that a high rate of proteid exchange is not a necessary requisite for the welfare of the body.
The experimental results presented afford very convincing proof that so far as body-weight and nitrogen equilibrium are concerned, the needs of the body are fully met by a consumption of proteid food far below the fixed dietary standards, and still further below the amounts called for by the recorded habits of mankind. General health is equally well maintained, and with suggestions of improvement that are frequently so marked as to challenge attention. Most conspicuous, however, though something that was entirely unlooked for, was the effect observed on the muscular strength of the various subjects. When the experiments were planned, it was deemed important to arrange for careful quantitative tests of the more conspicuous muscles of the body, with a view to measuring any loss of strength that might occur from the proposed reduction in proteid food. The thought that prompted this action was a result of the latent feeling that somehow muscular strength must be dependent more or less upon the proteid constituents of the muscles, and that consequently the cutting down of proteid food would inevitably be felt in some degree. The most that could be hoped for was that muscle tone and muscular strength might be maintained unimpaired. Hence, we were at first quite astonished at what was actually observed.
With the soldier detail, fifteen distinct strength tests were made with each man during the six months’ period, by means of appropriate dynamometer tests applied to the muscles of the back, legs, chest, upper arms, and forearms, reinforced by quarter-mile run, vault, and ladder tests, etc. The so-called “total strength” of the man was computed by multiplying the weight of the body by the number of times the subject was able to push up (strength of triceps muscles) and pull up (strength of biceps muscles) his body while upon the parallel bars, to this product being added the strength (dynamometer tests) of hands, legs, back, and chest. It should be added that all of these tests were made quite independently in the university gymnasium by the medical assistants and others in charge of the work there. It will suffice for our purpose to give here the strength tests of the various members of the soldier detail at the beginning and close of the experiment.
TOTAL STRENGTH
| October. | April. | |
|---|---|---|
| Broyles | 2560 | 5530 |
| Coffman | 2835 | 6269 |
| Cohn | 2210 | 4002 |
| Fritz | 2504 | 5178 |
| Henderson | 2970 | 4598 |
| Loewenthal | 2463 | 5277 |
| Morris | 2543 | 4869 |
| Oakman | 3445 | 5055 |
| Sliney | 3245 | 5307 |
| Steltz | 2838 | 4581 |
| Zooman | 3070 | 5457 |
Without exception, we note with all of the men a phenomenal gain in strength, which demands explanation. Was it all due to the change in diet? Probably not, for these men at the beginning of the experiment were untrained, and it is not to be assumed that months of practical work in the gymnasium would not result in a certain amount of physical development, with corresponding gain in muscular skill and power. Putting this question aside for the moment, however, it is surely proper to emphasize this fact; viz., that although the men for a period of five months were restricted to a daily diet containing only one-third to one-half the amount of proteid food they had been accustomed to, there was no loss of physical strength; no indication of any physical deterioration that could be detected. In other words, the men were certainly not being weakened by the lowered intake of proteid food. This is in harmony with the principle, already discussed, that the energy of muscle work comes primarily from the breaking down of non-nitrogenous material, and consequently a diminished intake of proteid food can have no inhibitory effect, provided, of course, there is an adequate amount of proteid ingested to satisfy the endogenous requirements of the tissues.
On the other hand, recalling the large number of nitrogenous cleavage products which result from the breaking down of proteid material, we can conceive of an exaggerated exogenous proteid katabolism which may flood the tissues and the surrounding lymph with a variety of nitrogenous waste products, having an inhibitory effect upon the muscle fibres themselves, or upon the peripheral endings of the motor nerves, by which the muscles are prevented, directly or indirectly, from working at their highest degree of efficiency. This being true, a reduction of the exogenous katabolism to a level more nearly commensurate with the real needs of the body might result in a marked increase in the functional power of the tissue. However this may be, the fact remains that all of the subjects showed this great gain in strength; and furthermore, there was a noticeable gain in self-reliance and courage in their athletic work, both of which are likewise indicative of an improved condition of the body. How far these improvements are attributable to training and to the more regular life the men were leading, and how far to the change in diet, cannot be definitely determined. We may venture the opinion, however, for reasons to be made clear shortly, that the change in diet was in a measure at least responsible for the increased efficiency. As the writer has already expressed it, there must be enough food to make good the daily waste of tissue, enough food to furnish the energy of muscular contraction, but any surplus over and above what is necessary to supply these needs is not only a waste, but may prove an incubus, retarding the smooth working of the machinery and detracting from the power of the organism to do its best work.
Let us now turn our attention for a moment to the group of university athletes, remembering that these men had been in training for many months, and some of them for several years, prior to the commencement of the trial with a reduced proteid intake. In the words of the director of the gymnasium, “These eight men were in constant practice and in the pink of condition; they were in ‘training form’ when they began the changed diet.” Some of them had gained marked distinction for their athletic work; one during the early months of the test won the Collegiate and All-around Inter-collegiate Championship of America. Compare now the strength tests of these men as taken at the beginning and end of the five months’ experiment, during which they reduced their daily intake of proteid food more than fifty per cent:
TOTAL STRENGTH
| January. | June. | |
|---|---|---|
| G. W. Anderson | 4913 | 5722 |
| W. L. Anderson | 6016 | 9472 |
| Bellis | 5993 | 8165 |
| Callahan | 2154 | 3983 |
| Donahue | 4584 | 5917 |
| Jacobus | 4548 | 5667 |
| Schenker | 5728 | 7135 |
| Stapleton | 5351 | 6833 |
It is to be observed that the majority of these trained men showed at the first trial in January a total strength test approximately equal to that of the soldier detail at the close of their experiment. This by no means implies that the latter men owed their gain in strength wholly to the systematic training they had undergone, but it is certainly plausible to assume that in a measure this was the case. In any event, it is plain that the long-continued low proteid diet of the soldiers had not interfered with a progressive muscular development, and the attainment of a high degree of muscular strength.
The noticeable feature in the figures obtained with the athletes, however, is the striking difference between the January and June results. Every man, without exception, showed a decided gain in his muscular power as measured by the strength tests. This improvement, to be sure, was not so marked as with the soldiers; a fact to be expected, since with these men the element of training and the acquisition of proficiency in athletic work could have played no part in the observed gain. Further, most of the tests indicated that the gain was progressive, each month showing an improvement, in harmony with the growing effect of the diminished proteid intake. With these subjects, the only tangible change in their mode of life which could in any sense be considered as responsible for their gain in strength was the change in diet. Consequently, it seems perfectly justifiable to conclude that the observations presented afford reasonable proof of the beneficial effects of a lowered proteid intake upon the muscular strength of man.
The significance of such a conclusion is manifestly obvious. It confirms and gives added force to the observations that man can profitably maintain nitrogen equilibrium, and body-weight, upon a much smaller amount of proteid food than he is accustomed to consume. It harmonizes with the view that the normal requirements of the body for food, under which health, strength, and maximum efficiency are best maintained, are on a far lower level than the ordinary practices of mankind would lead one to believe. The widespread opinion that a rich proteid diet, with the correspondingly high rate of proteid metabolism, is a necessity for the preservation of bodily strength and vigor, is seen to be without foundation; for even the most conservative estimate of the real value of these strength tests must carry with it the conviction that lowering the consumption of proteid food does not at least result in any weakening of the body. This is a fact of vital importance, for it needs no argument to convince even the most optimistic that while it might be possible to maintain body-weight and nitrogen equilibrium on a small amount of proteid food, such a form of physiological economy would not only be of no advantage to the individual, but would be positively injurious if there was a gradual weakening of the muscles of the body with decrease of physical strength, vigor, and endurance.
Another fact to be emphasized in this connection was the conviction, gradually acquired by many of the subjects, that they suffered less from fatigue after vigorous muscular effort than formerly. This was especially conspicuous in the case of Donahue, whose work on the Varsity basket-ball team called for vigorous exercise. It is interesting to note that this athlete, of 63 kilos body-weight, for the last four months of the experiment showed an average daily katabolism of 7.45 grams of nitrogen, corresponding to a breaking down of 46.5 grams of proteid material daily. Yet, with this low rate of proteid exchange, he maintained his position on the team with satisfaction to all, and with the consciousness of improved physical condition and greater freedom from fatigue. Other subjects, as the laboratory workers of the professional group, observed that the customary late afternoon fatigue, coincident with the continued walking and standing about the laboratory, gradually became far less conspicuous than usual; so that there seemed to be a consensus of opinion that in some way the change in diet was conducive to greater freedom from muscular weariness.
It is well understood by physiologists that the ability of a muscle to do work is inhibited by any condition that tends to depress the general nutritive state of the body, or that interferes with the local nutrition of the muscle or muscles involved. On the other hand, there are certain well-recognized conditions that tend to augment the power of the muscle, notably an increased circulation of blood through the tissue, the taking of food, and especially the introduction of sugar. Further, experiments have shown that when a given set of muscles has been made to work excessively, other muscles of the body quite remote will share in the fatigue, thus implying that muscular weariness and the diminished power to do work are connected with what may be termed fatigue products, which are distributed by means of the circulation. In this way, muscles and nerve endings alike are exposed to the inhibitory influence of waste products of unknown composition, formed in the muscle, and as previously stated, we may conceive of an exaggerated exogenous katabolism, with excessive proteid intake, by which muscular fatigue and weariness may be augmented; hence, the beneficial effect in this direction of a more rational food consumption, by which proteid katabolism shall be reduced to a true physiological level.
With these marked effects on strength and fatigue, it is reasonable to assume that some corresponding action may be exerted on physical endurance. As is well known, strength and endurance, though related, are quite distinct and can be separately measured. Strength tests, however, as usually carried out in gymnasium work, do involve in considerable degree the question of endurance, since it is customary to use as one of the factors in estimating total strength the number of times the man can pull up, or push up, his body on the parallel bars. Strictly speaking, however, the strength of a muscle is measured by the maximum force it can exert in a single contraction, while its endurance is estimated from the number of times it can contract well within the limit of its strength.
It is well known that endurance, both physical and mental, is one of the most variable of the human faculties, and it is usually considered that exercise or training is the chief cause of the differences so frequently seen. The Maine guide will row a boat or paddle a canoe for the entire day without undue fatigue, while the novice, though he may have the necessary strength, lacks the endurance to continue the task longer than a few hours. As expressed by Professor Fisher, “Some persons are tired by climbing a flight of stairs, whereas the Swiss guides, throughout the summer season, day after day spend the entire time in climbing the Matterhorn and other peaks; some persons are ‘winded’ by running a block for a street car, whereas a Chinese coolie will run for hours on end; in mental work, some persons are unable to apply themselves more than an hour at a time, whereas others, like Humboldt, can work almost continuously through eighteen hours of the day.” Again, Fisher states that “among some 75 tests of different persons holding their arms horizontal, many were found whose arms actually dropped against their will inside of 10 minutes, whereas several were able to hold them up over 1 hour, and one man held them 3 hours and 20 minutes, or a round 200 minutes, and then dropped them voluntarily. Similarly with deep knee-bending, some persons were found physically unable to rise again from the stooping posture after accomplishing less than 500 bendings, whereas several succeeded in stooping 1000 times, and in one case, 2400.” Here, we have inherent differences in endurance not associated with training or exercise, and the question may well be asked, What is the cause of these radical variations in the ability to repeat a simple muscular exertion?
Hitherto, little attention has been paid to the possible influence of diet upon this faculty. It has always been assumed that endurance, like physical strength, is augmented by a rich proteid diet, but it has never been considered that diet by itself was a factor of any great moment as compared with training or persistent exercise. It is true that claims have been advanced from time to time concerning the beneficial effects on endurance of a vegetable diet, and vegetarians have frequently presented glowing reports of the great increase in endurance they have experienced, but little attention has been given to such statements, and the matter has remained more or less in obscurity.
Recently, Professor Irving Fisher,[63] of Yale, has conducted an interesting experiment on the influence of a change in diet on endurance, having the co-operation of nine healthy students as subjects. The experiment extended through five months, with endurance tests at the beginning, middle, and end of the period. At the outset, the men consumed daily an average of 2830 calories, of which 210 were in the form of flesh foods, such as meats, poultry, fish and shell-fish; 2.6 calories of proteid being ingested for each pound of body-weight. At the close of the experiment, the per capita calories had fallen to 2220, of which only 30 were in flesh foods, and the proteid had fallen to 1.4 calories per pound of body-weight. In other words, the total calories of the daily ration had dropped off about 25 per cent, the proteid about 40 per cent, and the flesh foods over 80 per cent, or to about one-sixth of their original amount.
To determine the endurance of the subjects, six simple gymnastic tests were employed, and one of mental endurance. The physical tests consisted of (1) in rising on the toes as often as possible; (2) deep knee-bending, or stooping as far as possible and rising to the standing posture, repeating as often as possible; (3) while lying on the back, raising the legs from the floor to a vertical position and lowering them again, repeating to the point of physical exhaustion; (4) raising a 5-lb. dumb-bell (with the triceps) in each hand from the shoulder up to the highest point above the head, repeating to the point of physical exhaustion; (5) holding the arms from the sides horizontally for as long a time as possible; (6) raising a dumb-bell (with the biceps) in one hand from a position in which the arm hangs free, to the shoulder and back, repeating to the point of physical exhaustion. This test was taken with four successive dumb-bells of decreasing weight, viz., 50, 25, 10, and 5 pounds respectively. The mental test consisted in adding specified columns of figures as rapidly as possible, the object being to find out whether the rapidity of performing such work tended to improve during the experiment.
The following table shows the results of the three sets of physical tests made in January, March, and June:
TESTS OF PHYSICAL ENDURANCE WITH THE NINE SUBJECTS
| Time. | B. | E. | Lq. | Lw. | M. | P. | R. | T. | W. | |
|---|---|---|---|---|---|---|---|---|---|---|
| 1. Rising on | Jan. | 300 | 1007 | 333 | 69 | 127 | 1482 | 702 | 900 | 1263 |
| toes | Mar. | 400 | 1265 | 2620 | 65 | 400 | 831 | 1500 | ||
| June | 500 | 1061 | 3000 | 85 | 1500 | 1800 | 1263 | 1800 | 3350 | |
| 2. Deep knee- | Jan. | 82 | 142 | 70 | 48 | 132 | 208 | 374 | 129 | 404 |
| bending | Mar. | 191 | 47 | |||||||
| June | 200 | 81 | 202 | 58 | 155 | 230 | 453 | 250 | 508 | |
| 3. Leg | Jan. | 25 | 52 | 9 | 22 | 30 | 27 | 50 | 23 | 30 |
| raising | Mar. | 33 | 34 | 40 | ||||||
| June | 33 | 38 | 20 | 35 | 31 | 37 | 103 | 19 | 53 | |
| 4. 5lb. | Jan. | 75 | 138 | 78 | 38 | 51 | 44 | 100 | 83 | 185 |
| Dumb-bell | Mar. | 106 | ||||||||
| (triceps) | June | 127 | 59 | 80 | 51 | 75 | 56 | 104 | 101 | 501 |
| m. s. | m. s. | m. s. | m. s. | m. s. | m. s. | m. s. | m. s. | m. s. | ||
| 5. Holding | Jan. | 5–0 | 1–33 | 4–7 | 3–37 | 3–30 | 5–39 | 2–5 | 3–22 | 11–0 |
| arms hori- | Mar. | 5–49 | 15–35 | |||||||
| zontal | June | 9–36 | 2–56 | 3–50 | 3–0 | 6–5 | 10–1 | 3–16 | 3–24 | 23–45 |
| 6. 25lb. | Jan. | 50 | 18 | 16 | 6 | 20 | 11 | 10 | 25 | 54 |
| Dumb-bell | June | 105 | 10 | 26 | 33 | 30 | 29 | 27 | 75 | 108 |
| (biceps) |
The data presented show a marked improvement in March and June over the record made at the beginning of the experiment in January, except in the case of one subject, E. As Fisher states, the increased endurance observed can be ascribed only to dietetic causes, since no other factors of known significance could have aided in the result. The dietetic changes, as we have seen, consisted in a slight reduction of the total amount of food consumed daily, but with a large reduction of the proteid element, especially from flesh foods. It is significant, says Fisher, that the only man whose strength and endurance showed any decrease was E, “whose case was exceptional in almost all respects. His reduction in quantity of food, except for a spurt at the end, was less than of most of the men; his reduction in proteid, with the same exception, was the least of all; his reduction in quantity of flesh foods was the least of all.” He stands out conspicuously as the one man whose endurance failed to improve. The mental test carried out with the subjects pointed to “a slight increase in mental quickness,” but the adding test was too short to be of great value.
We see in these results another confirmation of the view that the welfare of the body is not impaired by a marked reduction in the amount of proteid food; on the contrary, benefit results in the increased efficiency which manifests itself in various directions. Physical endurance is an asset not to be ignored, and like the strength of an individual, it may well be fostered by the recognition and practice of a principle which seemingly has a firm physiological basis. Whether the fatigue poisons come from the excessive exogenous katabolism of proteids in general, or whether they are derived directly in a measure from flesh foods, need not be considered here; the main point is that by lowering the rate of proteid katabolism, which necessarily compels a reduction in the amount of flesh foods, there is a diminished quantity of nitrogenous waste floating about in the body. Further, we need not criticise too closely the method by which the reduction of food is accomplished; whether it be by encouraging mastication, with a view to better tasting and fuller enjoyment of the food, to the point of involuntary swallowing; or whether we follow natural taste and appetite, reinforced by the use of reason, with a full appreciation of the principle that the welfare of the body is best subserved by a quantity of food commensurate with true physiological needs.
In making this presentation of the true food requirements of the body as based on the results of physiological experimentation and observation, I am by no means unmindful of the dangers of underfeeding; but this is a condition comparatively rare. When occurring, as stated by Dr. Curtis, “it is either because of dyspepsia, in which case it really is involuntary, or comes from some silly notion born of a combination of innate mental crookedness and that ‘little knowledge’ that is a dangerous thing.” Overfeeding is the predominant dietetic sin, and with the prevailing dietary standards, as fixed by common usage, there is good ground for believing that it will continue for many years to come. Reason tells us, however, in the practice of our personal nutrition, to steer a middle course between physiological excess on the one side, and the minimal food requirement on the other. To quote again from Dr. Curtis,[64] who has expressed the matter very forcibly, “The physiological chemist can easily draw a line on the Scylla (starvation) side of the channel. A dietary whereby the system gets less than it pays out is, obviously, a dangerous veer toward starvation rock. But on the Charybdis (stuffing) side, just as the whirlpool itself has no well-defined border, the channel boundary is not so easily marked. The case is exactly analogous to the stoking of a furnace. The proportion of ash to live coals is a telltale as to underfeeding, but not as to overfeeding. With undersupply of fuel the ashes overbalance the live coals, and the fire is thus foretold to be going out. But with an oversupply the fire simply burns the faster: all the fuel continues to be consumed; the more coal simply makes the more ash, so that equilibrium is not disturbed, although maintained at a higher level. To argue, therefore, that a given dietary is none too large, because the balance between the material receipts and expenditures of the economy is not upset, would be like saying that a given furnace-fire is certainly none too hot, since the ashes raked out of the fire-box just correspond to the amount of coal shovelled in. The same would be equally true of a slower fire consuming much less fuel. The philosophy of the matter is, then, to find the minimum of steam that will run the engine, and then maintain a fire somewhat hotter than the exact requirement, in order to run no risk of failure; or, to return to the metaphor already employed, the would-be careful liver must simply note how close to Scylla other voyagers have sailed with safety, and then steer his own bark accordingly.”
As one looks through the many careful dietary studies that have been made in recent years, it is easy to find striking illustrations of people, and communities of people, who have lived for long periods of time on dietaries so strikingly simple and meagre that it seems difficult at first glance to believe their daily needs could have been entirely satisfied. Yet, such observations are quite in accord with the facts we have been presenting, and they afford additional evidence that the artificial dietary standards that have been set up are widely at variance with the real requirements of the body for food. It may be quite true that many of the people referred to have been and are faddists, with peculiar notions regarding food, based on religious or other scruples, but that has no bearing on the main contention that they have lived for many years on amounts of food ridiculously small as compared with the ordinary customs of mankind. Thus, in Professor Jaffa’s report[65] of investigations made among fruitarians and Chinese of California is an interesting account of a dietary study of a family of fruitarians, consisting of two women and three children. They had all been fruitarians from five to seven years, their diet being limited to nuts and fruit, except for the addition of celery, honey, olive oil, and occasionally a small amount of prepared cereal food. This family was in the habit of taking only two meals a day; at 10.30 in the morning and at 5 o’clock in the afternoon. The first meal always consisted of nuts and fruit, the nuts being eaten first. At the second meal, nuts were usually replaced by olive oil and honey. The nuts made use of were almonds, Brazil nuts, pine nuts, pignolias (a variety of pine nuts), and walnuts. Fruits, both fresh and dried, were used, the former including apples, apricots, bananas, figs, grapes, olives (pickled), oranges, peaches, pears, plums, and tomatoes. The dried fruits were dates and raisins.
On this limited dietary of raw, uncooked food, with a complete absence of the high-proteid animal foods, and the ordinary vegetables, legumes, etc., and without eggs or milk, this family, with three growing children, had lived all these years. Note now what Jaffa observed regarding their food consumption. The first subject, a woman 33 years of age and weighing 90 pounds, was studied for twenty consecutive days, all the food eaten being carefully weighed and its chemical composition determined. As a result, it was found that the average amount of food consumed per day was: proteid, 33 grams; fat, 59 grams; carbohydrate, 150 grams; with a total fuel value of 1300 calories. The other members of the family were studied in a similar manner, one of the children being the subject on two separate occasions. The table (on page 217), showing the average daily food consumption, gives a summary of the results obtained.
| Proteid. | Fat. | Carbo- hydrate. | Fuel Value. | Proteid per Kilo Body- weight. | |
|---|---|---|---|---|---|
| grams | grams | grams | calories | grams | |
| Woman, 33 years old, Weight 90 lbs. (40.9 kilos) | 33 | 59 | 150 | 1300 | 0.80 |
| Woman, 30 years old, Weight 104 lbs. (47.3 kilos) | 25 | 57 | 90 | 1040 | 0.52 |
| Girl, 13 years old, Weight 75 1/2 lbs. (34.3 kilos) | 26 | 52 | 157 | 1235 | 0.75 |
| Boy, 9 years old, Weight 43 lbs. (19.5 kilos) | 27 | 56 | 152 | 1255 | 1.38 |
| Girl, 6 years old, Weight 30 1/2 lbs. (13.9 kilos) | 24 | 58 | 134 | 1190 | 1.72 |
| Girl, 7 years old, Weight 34 lbs. (15.4 kilos) | 40 | 72 | 134 | 1385 | 2.59 |
As Professor Jaffa states, the tentative dietary standard for a woman at light work calls for 90 grams of proteid daily, with a fuel value of 2500 calories. Both of these women were light in weight, and furthermore had no occasion to do much physical work; but even so, a daily consumption of only 0.8 gram and 0.52 gram of proteid, respectively, per kilo of body-weight, with the small calorific values indicated, represents a phenomenally small amount of food. And yet Jaffa, in referring to the woman with the lowest intake of food, states that even this small quantity of food, judging from the appearance and manner of the subject, “seemed sufficient for her needs, enabling her to do her customary housework and take care of her two nieces and nephew.” Regarding the children, it is stated that the commonly accepted American dietary standard for a child 13 years old and of an average activity calls for about 90 grams of proteid and 2450 calories. As is seen from the table, however, the 13-year-old girl consumed of proteid less than one-third, and of fuel value only about 60 per cent of the amount called for; yet, says Jaffa, “notwithstanding the facts brought out by this comparison, the subject had all the appearances of a well-fed child in excellent health and spirits.”
We need not consume time in discussing the details of this experimental study, though the facts are interesting and suggestive, for it is only the general question of proteid requirement and calorific value that has interest for us at present. The fact is perfectly clear that this family of fruitarians, young and old, were quite able to live and thrive on a diet, the value of which in proteid and calories was at as low a level as was attained in our experimental studies. The rock of starvation, however, was not touched or even sighted by the voyagers down this stream of nutrition. We may all agree that it would be preferable, as a rule, to acquire the proteids, fats, and carbohydrates of our diet from a greater variety of sources than did the fruitarians; we might well complain at a dietary so limited in quality; but the point to be emphasized is that the low intake of proteid and the low fuel value were quite adequate for meeting the needs of the body. “It is a difficult matter,” says Professor Jaffa, “to draw any general conclusions from the foregoing dietaries without being unjust to the subjects. It would appear, upon examining the recorded data and comparing the results with commonly accepted standards, that all the subjects were decidedly undernourished, even making allowances for their light weight. But when we consider that the two adults have lived upon this diet for seven years, and think they are in better health and capable of more work than they ever were before, we hesitate to pronounce judgment. The three children, though below the average in height and weight, had the appearance of health and strength. They ran and jumped and played all day like ordinary healthy children, and were said to be unusually free from colds and other complaints common to childhood.”
Turning now to a larger community,—the island nation of Japan,—whose exploits in war have recently attracted the attention of the civilized world, we find a people the great majority of whom have remained untouched by the prodigality of western civilization, and whose customs and habits still bear the imprint of simplicity and frugality. After the restoration of Japan and the reorganization of the government in 1867, much attention was directed to the methods of living and to the dietary habits of the people, with the result that during the last twenty-five years there have been slowly accumulating many important data bearing on the food consumption of the people. These have recently been brought together in an interesting volume by Kintaro Oshima, and published[66] in the English language.
| Subjects. | Body- | Digestible Nutrients and Energy per Man | |||
|---|---|---|---|---|---|
| Proteid. | Fat. | Carbo- | Fuel | ||
kilos | grams | grams | grams | calories | |
| School business agent | 57.5 | 65.3 | 11.3 | 493.8 | 2467 |
| Physician | . . . . | 61.9 | 8.0 | 468.5 | 2315 |
| Merchant | 47.6 | 81.5 | 19.6 | 366.2 | 2082 |
| Medical student | 49.0 | 74.8 | 11.2 | 326.9 | 1811 |
| Medical student | 48.5 | 64.7 | 5.1 | 469.6 | 2305 |
| Military cadets | . . . . | 72.3 | 11.7 | 618.1 | 3021 |
| Prisoners without work | 47.6* | 36.3 | 5.6 | 360.4 | 1726 |
| Prisoners at light work | 48.0* | 43.1 | 6.2 | 443.9 | 2112 |
| Prisoners at hard work | . . . . | 56.7 | 7.5 | 610.8 | 2884 |
| Physician | 40.2 | 48.3 | 15.5 | 438.2 | 2201 |
| Hygienic assistant | 40.5 | 46.5 | 19.7 | 485.3 | 2430 |
| Medical student | 51.0 | 42.8 | 14.0 | 438.2 | 2163 |
| Police prisoners | . . . . | 42.7 | 8.7 | 387.3 | 1896 |
| Army surgeon | 54.0 | 79.3 | 11.7 | 502.0 | 2567 |
| Soldier | 66.7 | 75.8 | 13.5 | 563.8 | 2828 |
| Soldier | 61.0 | 58.8 | 11.3 | 467.8 | 2330 |
| Soldier | 56.7 | 55.2 | 10.9 | 459.6 | 2276 |
* Average weight of twenty subjects.
As is well known, the great majority of the people of Japan live mainly on a vegetable diet. It is also known to physiologists at least that Japanese dietaries are characterized by a relatively small amount of proteid, though since the passage of the Food Supply Act of the navy in 1884, the proteid-content of the navy ration has been decidedly increased. It will be interesting to note a few of the results collated by Oshima, and some of the conclusions that he draws from the data presented. The foregoing table shows a few of the more striking results of the dietary studies obtained with various classes of people, where the food used was largely vegetable, but generally with some admixture of fish or meat.
The figures presented, which represent the actual amounts of food consumed, with proper correction for the indigestible portion, show a much smaller intake of proteid than is common with European and American people; indeed, both proteid and fuel value are very much less than common practices call for among western peoples, even when due allowance is made for differences in body-weight. To quote from Oshima, “Probably the most interesting of the dietary studies are those with poorer classes, which comprise by far the larger part of the population. The dietaries of the miscellaneous class, including employees, prisoners, etc., consisted largely of vegetable foods and supplied on an average 59 grams of proteid and 2190 calories of energy per man per day.” Especially suggestive were the results of a study made with a military colonist, a type of man very common in Japan; in reality farmers who live at home, but have military drill at certain fixed times. The subject was carefully selected under advice of officers in charge of the district, and weighed 59.9 kilograms. His diet consisted solely of cereals and vegetables, being identical with that of the people in the rural districts of Japan. His daily food was found to be composed of 46.3 grams of digestible proteid, with a fuel value of 2703 calories.
Even more striking were the results obtained in a study of the dietary habits of three healthy natives of Formosa, employed as day laborers at the military hospital. They weighed respectively 60.9, 55, and 54.8 kilograms. The main portion of their diet was rice, supplemented, however, by a little salt fish, salted melon, spinach, ginger, and greens. The daily amount of proteid ingested was 48.0 grams (37.4 grams of digestible proteid), with a total fuel value of 1948 calories. A composite sample of urine covering seven days showed an average daily output of metabolized nitrogen of 6.93 grams, corresponding to a breaking down of 43.3 grams of proteid.
Especially interesting also is a series of experiments with professional men, reported by Oshima, in which attention was paid to nitrogen balance. The following table shows the essential results:
Subject. | Body- | Character | Digestible Nutrients and Energy per Man per Day. | ||||
|---|---|---|---|---|---|---|---|
Proteid. | Fat. | Carbo- | Fuel | Nitrogen | |||
kilos | grams | grams | grams | calories | |||
N. K. | 43.1 | mixed diet | 72.7 | 18.3 | 380.7 | 2091 | + |
S. A. | 49.5 | mixed diet | 69.8 | 20.2 | 410.7 | 2222 | + |
N. K. | 42.9 | mixed diet | 64.4 | 8.5 | 396.3 | 2028 | + |
N. K. | 43.2 | mixed diet | 62.8 | 8.7 | 433.2 | 2178 | + |
N. K. | 43.0 | vegetable | 68.5 | 19.7 | 433.0 | 2303 | + |
N. K. | 43.9 | vegetable | 36.8 | 6.6 | 381.0 | 1824 | - |
N. K. | 42.4 | vegetable | 40.5 | 8.7 | 462.6 | 2200 | + |
S. A. | 49.6 | vegetable | 34.4 | 7.5 | 451.9 | 2119 | - |
S. A. | 49.9 | vegetable | 43.5 | 9.1 | 500.0 | 2376 | + |
It is to be observed that in all of the above experiments, excepting two, the subjects gained nitrogen even with the low proteid intake and the small fuel value of the day’s food. Particularly noteworthy, in harmony with previous statements, are the results of the sixth and seventh experiments. In the sixth experiment, the subject was not able to maintain nitrogen equilibrium on a diet containing 36.8 grams of digestible proteid and having a fuel value of 1825 calories, but by raising the intake of carbohydrate food (seventh experiment) to 462 grams daily, thereby increasing the fuel value of the daily ration to 2200 calories (with a slight increase in the proteid incidental thereto), the body was able to change its previous loss of nitrogen into a gain; in other words, the added carbohydrate served as a protector of proteid.
The series of experiments as a whole, however, is to be considered in the light of additional data bearing on the dietary customs of a people who for generations have apparently lived and thrived on a daily ration noticeably low in its content of proteid, as well as low in its calorific value. As Oshima states, “It is probably fair to infer that the amount of proteid in the dietaries of the classes living largely on vegetable foods (and they constitute the larger part of the population) may not be very far from 60 grams per day,” or 45 grams of digestible proteid. It is reasonable to assume that the people live in this way from force of habit or of necessity, and we may agree with Baelz, a professor connected with the medical faculty of Tokyo University, “that their diet is sufficient from a physiological standpoint.” Doubtless a mixed diet, with a larger proportion of animal food, did their means readily permit, would offer some advantages from the standpoint of palatability and variety, but it is questionable if any material gain in health or strength would result. “It is sometimes remarked,” says Oshima, “that the peasants in the rural districts of Japan, living largely on vegetable food, are really healthier and stronger than people of the better classes, who live on a mixed diet, and the better physical condition of the former is commonly believed to be due to their diet.” This, however, is a difficult matter to decide, since there are so many other factors that are liable to play a part, such as the general conditions of life which are so widely different in the two classes.
It is plainly evident that the daily diet of the great bulk of the Japanese people has been characterized by a very low proteid standard, as contrasted with the standards and usages of the majority of European and American people. The fact is brought forward merely as confirmatory evidence, on a large scale, of the perfect safety of lowering the consumption of proteid food to somewhere near the level of the physiological requirements of the body. Generations of low proteid feeding, with the temperance and simplicity in dietary matters thereby implied, have certainly not stood in the way of phenomenal development and advancement when the gateway was opened for the ingress of modern ideas from western civilization. Many changes are sure to follow in the footsteps of the nation’s progress, and among these it is safe to prophesy that as public and private wealth, and resources in general, increase, the dietary of the people will gradually assume a more varied character with corresponding increase in volume. Whether such a change will prove of real benefit to the race, time alone can determine.
Having said so much concerning the Japanese, it is proper that a few additional statements should be made. The stature and general physique of the people could be advantageously improved. Is this a question of dietary, or is it connected with some condition of life on which the daily food has no bearing; or is it, perchance, a racial characteristic so deeply ingrained that conditions of environment are without noticeable influence? These questions cannot be definitely answered at present. Finally, we may call attention to the dietary changes inaugurated in recent years in connection with the new organization of the imperial army and navy. With a view to increasing the efficiency of the men, following the customs of other countries, an act was passed increasing the amount of proteid food in the navy dietary. Oshima’s report of the various steps taken to accomplish this end, with the results that followed, is interesting in several ways.
“A large part of the rice was to be replaced by bread, and meats were to be used liberally. The experience, during the first year that this ration was tried, indicated that bread and meat could not be advantageously substituted immediately for the rice, because most of the marines were unaccustomed to these food materials; consequently, a modification of the ration was introduced in 1885, whereby a rice-barley mixture was adopted in place of the bread. Barley was considered at that time as a better article of food than rice, on account of its higher proteid content, but later investigations showed that the digestibility of the nutrients of barley was small. In 1886, an effort was again made to substitute bread for the rice-barley mixture. In 1890, the ration allowance was reduced by one-fifth and an amount of money equivalent to the cost of the reduction in diet was given to each marine with which to buy accessory food according to his own choice. In 1898, the reduction was made one-tenth, instead of one-fifth as in previous years. In 1900, the cash allowance was abolished and a new ration adopted.” This ration contains about 150 grams of proteid (animal and vegetable food) and has a fuel value of over 3000 calories. In all of these changes, the proportion of rice was greatly reduced.
Probably, one of the chief reasons why persistent efforts were made to improve the dietary of the navy was the prevalence among the men of the disease known as beriberi. “While no satisfactory explanation as to the cause of the disease was offered, it was generally believed that there was some very close relation between the disease and the rice diet” (Oshima). During the years 1878–1883 inclusive, nearly 33 per cent of the marines suffered from beriberi. With the adoption of the new ration in 1884, in which a large part of the rice was replaced by bread and other articles, and with better hygienic conditions, this disease immediately began to disappear, and during the six years after the adoption of the new diet only 16 per cent of the marines were affected by the disease. Later on, hardly more than two or three cases a year were recorded. Advocates of a high proteid diet bring forward this illustration as an evidence of the danger connected with a lowered proteid intake; i. e., that the nutrition of the body will be impaired and diseases of various sorts liable to follow. Yet, Oshima is very careful to state, “It should be especially noted that here no attempt has been made to indicate the cause of beriberi or the relation between the disease and the diet.” That rice in itself can be a cause of the disease is not to be considered for a moment. Further, so far as any facts are concerned, the writer can see no ground for considering that a low rate of proteid metabolism has in itself any direct connection with the disease. From a dietary standpoint, it seems far more plausible to assume that the great restriction in variety of foods, so strikingly manifest in the dietary of the poorer people of Japan, results in a lack of some one or more elements which conduces to the disease, just as in scurvy the lack of fresh vegetables on long voyages was liable to be followed by an epidemic of this disease.
Consider the natural character of the dietary of the great bulk of the Japanese people, determined as it was by adverse financial circumstances. As Oshima states, “The rural population of the interior depends very largely or entirely upon a vegetable diet. Fish is eaten perhaps once or twice a month, and meat once or twice a year, if at all. The poorer working classes in the cities also use very little animal food. But the poorer classes in the city and the peasantry of the rural districts comprise nearly 75 per cent of the total population, and it is therefore safe to assume that this proportion lives chiefly, or wholly, upon vegetable diet. And this, it may be observed, means vegetarianism literally. The so-called lacto-vegetarianism is unknown in Japan. Cows are scarce, and milk and other dairy products are expensive, and such as are available are consumed almost entirely by the wealthier people in the cities.” It is also to be noted that the amount of fat in Japanese dietaries is very small. The reported data indicate that the usual vegetable dietaries contain only about 10 grams of fat per day, while even in the average mixed dietaries the amount rarely rises above 20 grams per day. In other words, the ordinary food of the Japanese was characterized by great lack of variety, and with such a preponderance of carbohydrate materials of a limited kind that it is easy to conceive of a possible dearth of some essential or accessory element, necessary for the preservation of that nutritive balance which aids in protection against disease.
If the resistance of the body to disease germs and toxic influences in general is really diminished by reducing the consumption of proteid food below the set dietary standards, then obviously here lies a tangible reason for the maintenance of a high proteid intake. I know of only one series of scientific observations that bears directly on this question. Dr. Reid Hunt of Washington has studied recently the power of resistance to the poison acetonitrile of animals kept for some time upon a reduced proteid diet. “My experiments,” says Dr. Hunt, “showed in all cases that the resistance was much increased.” In other words, the animals that had been fed a low proteid ration were able to endure a much larger dose of the poison than corresponding animals on their customary diet; “they resisted 2–3 times the ordinary fatal dose of acetonitrile.” This general subject, however, is obviously a very important one, and merits further experimental study under a diversity of conditions.
In conclusion, the facts here presented bearing on food requirements, especially those that relate to the need for proteid food, are seemingly harmonious in indicating that the physiological necessities of the body are fully met by a much more temperate use of food than is commonly practised. Dietary standards based on the habits and usages of prosperous communities are not in accord with the data furnished by exact physiological experimentation. Nitrogen equilibrium can be maintained on quantities of proteid food fully fifty per cent less than the every-day habits of mankind imply to be necessary, and this without increasing unduly the consumption of non-nitrogenous food. A daily metabolism of proteid matter equal to an exchange of 0.10–0.12 gram of nitrogen per kilogram of body-weight is quite adequate for physiological needs, provided a sufficient amount of non-nitrogenous foods—fats and carbohydrates—is taken to meet the energy requirements of the body.
The long-continued experiments on many individuals, representing different types and degrees of activity, all agree in indicating that equilibrium can be maintained indefinitely on these smaller quantities of food, and that health and strength can be equally well preserved, to say nothing of possible improvement. The lifelong experience of individuals and of communities affords sufficient corroborative evidence that there is perfect safety in a closer adherence to physiological needs in the nutrition of the body, and that these needs, so far as proteid food is concerned, are in harmony with the theory of an endogenous metabolism, or true tissue metabolism, in which the necessary proteid exchange is exceedingly limited in quantity. There are many suggestions of improvement in bodily health, of greater efficiency in working power, and of greater freedom from disease, in a system of dietetics which aims to meet the physiological needs of the body without undue waste of energy and unnecessary drain upon the functions of digestion, absorption, excretion, and metabolism in general; a system which recognizes that the smooth running of man’s bodily machinery calls for the exercise of reason and intelligence, and is not to be intrusted solely to the dictates of blind instinct or to the leadings of a capricious appetite.