From this sample meal it will be seen that during the last five months of the experiment the men were living on about one-third of the proteid food to which they were accustomed.

"If," says Professor Chittenden, "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 the body-weight - in a 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:

6 Chittenden: "Nutrition of Man," pp. 193-197.

Table Of Body-Weights

"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. ... 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." 7

Professor Chittenden says that regarding the second point, viz., the nitrogen equilibrium, two different balance experiments with each of the men, one about the first of March and the other a month later, indicated plainly that the men were receiving more proteid food than was necessary to maintain their bodies in nitrogen equilibrium.

"The experiment results presented," says Professor Chittenden, "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.

7 Chittenden: "Nutrition of Man," pp. 198-200.

"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:

"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." 8

In order to ascertain how much of the improvement in the muscular strength, skill and endurance of the soldiers was due to the change in diet alone, as well as to demonstrate the fallaciousness of the old belief that a man doing heavy muscular work requires a large quantity of proteid food, Professor Chittenden secured as subjects for his next experiment a group of eight of the leading athletes of the University, all in "training form" and engaged constantly in violent muscular exercise. For five months they lived on a diet comprising not more than one-half to one-third the quantity of proteid food they had been in the habit of eating: as in the case of the soldiers, nitrogenous equilibrium was maintained, the weight, when once adjusted to the new level, remained practically constant and the gymnasium tests to which they were frequently subjected showed, in every man, a truly remarkable gain in strength and endurance.

8 Chittenden: "Nutrition of Man," pp. 202-204.

"Naturally," says Professor Chittenden, " in the case of these men the gain in strength recorded cannot be assigned to systematic training. The only change in their mode of living which can in any sense be considered as responsible for the improvement is the change in diet.

The main fact to be emphasized, however, is that these men - trained athletes, accustomed to living on relatively large amounts of proteid food - for a period of five months reduced their intake of proteid food more than fifty per cent, without loss of bodily strength, but, on the contrary, with a marked improvement in muscular power." 9