How to Live Part 16

[Sidenote: Basal Metabolism]

Francis G. Benedict and his co-workers at the Nutrition Laboratory of the Carnegie Inst.i.tution of Was.h.i.+ngton, and Prof. Graham Lusk of Cornell University, have also made a large number of experiments to ascertain what is termed the basal metabolism or heat production of the body at perfect rest, and also that under varying degrees of activity. The results are closely in agreement with the above.

Benedict has lately produced evidence to show that the basal metabolism, or heat production, at rest is not governed entirely by such factors as body weight and body surface, but by the amount and activity of the active protoplasmic cells of the body--the cells that compose the organs and muscles and blood. The condition of these cells when the measurements are taken (which may be influenced by age, sleep, previous muscular exercise and diet) materially affects the amount of heat production and the requirements in energy food. Such experiments show why a man must literally burn up his own body, if he takes in no fuel in the form of food. Benedict's views also account for the higher energy requirement of men as compared to women, who, as a rule, have more fat and less muscular tissue than men.

[Sidenote: Diet and Endurance]

We have quoted Rubner (_vide_ page 38) as condemning the very old popular idea that meat is very "strengthening." Actual experiments on this point have shown exactly the opposite to be the case. Meat eating and a high-protein diet instead of increasing one's endurance, have been shown, like alcohol, to actually reduce it.

An experiment was made by one of the authors to determine this question.

The experiment consisted of endurance tests made on 49 persons representing the two types of dietetic habits. The persons experimented upon const.i.tuted three cla.s.ses: first, athletes accustomed to high-protein and full-flesh dietary; second, athletes accustomed to a low-protein and non-flesh dietary; third, sedentary persons accustomed to a low-protein and non-flesh dietary. The subjects consisted of Yale students and instructors, a Connecticut physician, and several other physicians and nurses. All of the low-protein and non-flesh subjects except one had abstained from flesh foods for periods of 4 to 20 years, and 5 of them had never eaten such foods.

The experiments furnished a severe test of the claims of the flesh-abstainers. Two comparisons were planned, one between flesh-eating athletes and flesh-abstaining athletes, and the other between flesh-eating athletes and flesh-abstaining sedentary workers. The results would indicate that the users of low-protein and the non-flesh dietaries have far greater endurance than those who are accustomed to the ordinary American diet.

In the absence of any exact mechanical method of measuring endurance, simple endurance tests were employed, such as holding the arms horizontally as long as possible and deep knee bending. The tests were made before witnesses.

The comparison for arm holding shows a great superiority on the side of the flesh-abstainers. Only 2 of the 15 flesh-eaters succeeded in holding their arms out over a quarter of an hour, whereas 22 of the 32 abstainers surpa.s.sed that limit. None of the flesh-eaters reached half an hour, but 15 of the 32 abstainers exceeded that limit. Of these 9 exceeded an hour, 4 exceeded 2 hours and 1 exceeded 3 hours.

In respect to deep knee bending, if we take the number 325 for reference, we find that, of the 9 flesh-eaters only 3 surpa.s.sed this figure, while of the 21 abstainers, 17 surpa.s.sed it. Only 1 of the 9 flesh-eaters reached 1,000 as against 6 of the 21 abstainers. None of the former surpa.s.sed 2,000 as against 2 of the latter.

Similar results have been found in other investigations. It is probable that the inferiority of meat-eaters in staying power is due primarily to high protein, not to meat _per se_.

In 1906, nine Yale students under the direction of one of the authors experimented with Mr. Horace Fletcher's method of thorough mastication and instinctive eating. The experiment began with an endurance test on January 14, and consisted mainly of two parts, each of which lasted about ten weeks.

The object of the first half of the experiment was to test the claims which have been made as to the effects upon endurance of thorough mastication combined with implicit obedience to appet.i.te. Our conclusion in brief is that these claims, so far as they relate to endurance, are justified.

The method may be briefly expressed in two rules.

1. _Mastication._--Thorough mastication of all food up to the point of involuntary swallowing, with the attention directed, however, not on the mechanical act of chewing, but on the tasting and enjoyment of the food; liquid foods to be sipped and tasted, not drunk down like water. There should be no artificial holding of food in the mouth beyond the time of natural swallowing, even if, as is to be expected at the start, that swallowing is premature. It is not intended to "count the chews," or to hold the food forcibly in the front of the mouth, or to allow the tongue muscles to become fatigued by any unnatural effort or position, or in any other way to make eating a bore. On the contrary, every such effort distracts one from the natural enjoyment of food. Pavlov has shown that without such attention and enjoyment of the taste of food, the secretion of gastric juice is lessened. The point of involuntary swallowing is thus a variable point, gradually coming later and later as the practise of thorough mastication proceeds, until the result is reached that the food remains in the mouth without effort and becomes practically tasteless. Thus the food, so to speak, swallows itself, and the person eats without thought either of swallowing or of not swallowing it; swallowing is put into the same category of physiological functions as breathing, which ordinarily is involuntary.

2. _Following instinct._--Never to eat when not hungry, even if a meal (or more than one, for that matter) is skipped. And when a meal is taken, not to be guided by the quant.i.ty of food offered, or by past habit, or by any theories as to the amount of food needed. The natural taste or appet.i.te is alone consulted, and the subject selects, from the food available, only those kinds and amounts which are actually craved by the appet.i.te. After practise, the appet.i.te gradually becomes more definite and discriminating in its indications.

During the second half of the experiment the two rules above mentioned were continued in force, but a third rule was added, namely, when the appet.i.te was in doubt, to give the benefit of that doubt to low-protein and non-flesh foods. In other words, the influence of suggestion was invoked to hasten the change which had been inaugurated by arousing the natural appet.i.te. Suggestion was introduced merely because the experiment was limited in time. In no case was it allowed to override the dictates of appet.i.te.

Careful records of the amount of food taken and the const.i.tuents in (1) protein, (2) fats and (3) starches and sugars, were kept for each man for each day. In order to avoid weighing the food at the table and the annoyance which such a procedure involves, the food was all weighed in the kitchen and served in definite portions of known food value. From the records thus supplied, it was easy, by means of a "mechanical diet indicator" devised for the purpose, to find the proportions of food elements. The first result of the experiment was a reduction in the amount of protein consumed.

During the first four weeks, the men consumed an average of from 2,760 to 3,030 calories per day, of which 120 to 240 were in the flesh foods, such as meats, poultry, fish and sh.e.l.l-fish, and that 2.4 to 2.7 calories of protein were ingested for each pound of body-weight.

Translating Professor Chittenden's figures for the physiological requirement of ingested protein, we find it to be from 1.3 to 1.7 calories per pound of body-weight. Thus the men were at this time consuming nearly double the Chittenden allowance. During the last four weeks of the experiment all these magnitudes were lower. The per capita calories ranged from 2,220 to 2,620, of which only 40 were in flesh foods, and the protein had fallen to 1.4 to 1.9 calories per pound of body-weight, which corresponds closely to the Chittenden standard.

Gymnasium tests were made at the beginning, middle and end of the experiment. These tests were of two kinds--tests of strength and tests of endurance.

During the first period there was a slight increase in strength (from an average "total" strength of 1,076 to 1,118), and during the second period a slight fall to 995, which is about 12 per cent. from the mid-year's 1,118, and about 8 per cent. from the original 1,076. Thus the strength of the men remained nearly stationary throughout the experiment.

It is fortunate that the strength of the men remained so nearly stationary; for it demonstrates the more clearly that the increase in endurance which will be shown below was an increase in endurance _per se_, and not in any degree due to an increase in strength. Strength and endurance are entirely distinct and should be separately measured.

The strength of a muscle is measured by the utmost force which it can exert _once_; its endurance by the number of times it can repeat a given exertion _well within its strength_.

After much consideration and consultation it was decided not to place reliance on the ordinary ergographs as a means of measuring endurance.

Instead, seven simple gymnastic tests of physical endurance were employed, and one of mental endurance. The seven physical tests were:

(1) Rising on the toes as many times as possible.

(2) Deep knee bending, or squatting 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 down, up to the shoulder and lowering it again, repeating the motion to the point of physical exhaustion. This test was taken with four successive dumb-bells of decreasing weight, viz., 50, 25, 10 and 5 lbs. respectively.

(7) Running on the gymnasium track at a speed to suit the subject, to as great a distance as possible.

The mental test consisted of 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.

PERCENTAGE OF IMPROVEMENT IN ENDURANCE (EXACT OR UNDERSTATED) OF EIGHT MEN.

AVERAGE.

B Lq. Lw. M P R T W Jan.-Mar. 33+ 36 50 -- 26 18+ 66+ 33 Jan.-June 84+ 84+ 181 29 56+ 89+ 80+ 107+

The figures of this table show an undoubted increase in endurance, both for the first half and more especially for the whole period of the experiment.

Three methods of estimating the increase of endurance between January and June were used. These may be put together in the following table:

PERCENTAGE OF INCREASE OF ENDURANCE, JANUARY TO JUNE, BY THREE METHODS.

AVERAGE SIX TESTS.

B E Lq. Lw. M P R T W 85 13 194 95 212 56+ 73 66 109

OMITTING DOUBTFUL CASES "+"

84+ ... 84+ 181 29+ 56+ 89+ 80+ 107+

"PURE" ENDURANCE OF BICEPS.

... ... 62 ... 50 ... 170 200 100+

The first line of this table tells us the average of the recorded improvement in endurance shown for each man. The average of these averages is 101 per cent. for the entire club, and is probably within the truth; for most of the individual figures which go to make up this result are understatements, not overstatements.

The second line shows the average improvement in tests in which there is no doubt that the figure is at least not too high, though it may be too low. The average of these is 89 per cent., and is therefore certainly too low an estimate of the average improvement for the eight men who improved at all.

The third line shows the increase of _pure_ endurance (that is, endurance considered apart from strength) for the five men for whom the figures were available. The average of these is 116 per cent.

We are quite safe in saying, therefore, that the average improvement of the eight men who improved was 90 per cent.

The phenomena observed during the experiment may be summarized as a slight reduction of total food consumed, a large reduction of the protein element, especially of flesh foods, a lessened excretion of nitrogen, a reduction in the odor, putrefaction, fermentation and quant.i.ty of the feces, a slight loss of weight, a slight loss of strength, an enormous increase of physical endurance, a slight increase in mental quickness. These phenomena varied somewhat with different individuals, the variations corresponding in general to the varying degree in which the men adhered to the rules of the experiment.

That we are correct in ascribing the results, especially in endurance, to dietetic causes alone, cannot reasonably be doubted when it is considered that no other factors of known significance were allowed to aid in this result.

While the results of the present experiment lean toward "vegetarianism,"

they are only incidentally related to its propaganda. Meat was by no means excluded; on the contrary, the subjects were urged to eat it if their appet.i.te distinctly preferred it to other foods.