“It is, to say the least, remarkable that hitherto so little effort has been directed toward discovering the factors which explain such differences in endurance. That exercise is one of the most and perhaps the most important factor has long been recognized. A correspondent assures me that by means of moderate regular exercise he succeeded in increasing his endurance between 100 and 200% in three weeks as measured by leg-raising and “dipping.” The influence of diet has always been regarded as small or negligible, and the opinion has almost been universal, until recently, that a diet rich in proteid promotes endurance. Even among those whose researches have led them to the opposite conclusion, there is very little conception of the extent to which diet is correlated with endurance. Such a person, a medical friend of the writer, stated, when the present experiment was planned, that he did not think the dietetic factor strong enough compared with others to produce any marked effect. We have all heard, of course, of the enthusiastic reports of vegetarians as to their increased endurance, but these we have discounted as exaggerations. The result of the present experiment, however, would seem to indicate that one’s improvement in endurance is usually not less, but greater, than he himself is aware of. Probably it is also true that we may lose a large fraction of our working power before we are distinctly conscious of the fact.
“While the results of the present experiment lean toward ‘vegetarianism,’ they are only incidentally related to that propaganda. Meat was by no means excluded; on the contrary, the subjects were urged to eat it if their appetite distinctly preferred it to other foods.
“The sudden and complete exclusion of meat is not always desirable, unless more skill and knowledge in food matters are employed than most persons possess. On the contrary, disaster has repeatedly overtaken many who have made this attempt. Pawlow has shown that meat is one of the most, and perhaps the most, ‘peptogenic’ of foods. Whether the stimulus it gives to the stomach is natural, or in the nature of an improper goad or whip, certain it is that stomachs which are accustomed to this daily whip have failed, for a time at least, to act when it was withdrawn.
“Nor is it necessary that meat should be permanently abjured, even when it ceases to become a daily necessity. The safer course, at least, is to indulge the craving whenever one is ‘meat hungry,’ even if, as in many cases, this be not oftener than once in several months. The rule of selection employed in the experiment was merely to give the benefit of the doubt to the non-flesh food; but even a slight preference for flesh foods was to be followed.
“Under flesh foods are included all meat and ‘stock’ soups. It has been shown that although these extracts of meat contain a large amount of nitrogen, it is not in the form of proteid which can be utilized, but only of waste nitrogen which must be excreted. Apparently the sole virtue of such soups is that they supply the ‘peptogenic’ stimulus above referred to.
ANYBODY CAN APPLY THE NEW KNOWLEDGE
“The practical value of the experiment consists in the fact that any layman can apply it, with or without a knowledge of food values, though with more advantage if he possess than if he lack such knowledge. If the dietetic rules of the present experiment are followed, no self-denial as to foods is required. It is, however, absolutely necessary that there should be self-control enough to break up the habit of hurried eating to which modern civilization has brought us—habituating us, as it were, to eat against time.
“Experience indicates that appetite does not lead to a diet fixed in amount or constituents, but moves in undulating waves or cycles. The men who took part in the experiment were encouraged, after any of the symptoms which seemed to be associated with high proteid (such as heaviness, sleepiness, stiffness, or soreness after exercise, or catching cold), to cut down on their proteid and substitute fat to restrain the gastric juice. This advice was intended to make application of the theories of Folin that we usually carry a reservoir of proteid, enough to supply our needs for body-building for a fortnight. If this reservoir is exhausted, proteid starvation occurs and the body feeds on itself; if it is filled too far it overflows and causes the evils of excessive proteid. If this theory is correct, the art of eating may consist largely in maintaining a golden mean, such that the proteid reservoir is neither empty nor overflowing much. Many persons fear to reduce their proteid to the Chittenden minimum for fear of proteid starvation; but the experience of those who have tried it would seem to show that this fear is groundless, provided no violence is done to natural appetite. This may be trusted, so it would appear, to raise a warning in the form of ‘nitrogen hunger,’ before the danger point is reached.” In other words, the body will ask in the language of hunger for proteid food, if you are not eating as much as you should. Professor Fisher considers that an amount of meat equivalent to about one small chop will supply all the proteid necessary in the daily ration, since proteid is also consumed in bread, potatoes and nearly all other foods.
It might be added that one of the writers has found the remedy for continual bilious headaches in the rigid exclusion from his diet of all foods that are rich in proteids, including meat, fish, eggs, milk, cheese, peas and beans; and maintains weight and working efficiency upon such amount of proteid as he derives from ordinary breadstuffs. He has found that the craving for high proteid foods soon disappears if it is not gratified; and that the quantity of bread, potatoes, etc., which the average person would eat at dinner and supper supplies all the nitrogen which his system needs, without leaving any to cause autointoxication.