CHAPTER VIII
PRACTICAL APPLICATIONS WITH SOME ADDITIONAL DATA
Topics: Proper application of the results of scientific research helpful to mankind. Dietary habits should be brought into conformity with the true needs of the body. The peculiar position of proteid foods emphasized. The evil effects of overeating. What the new dietary standards really involve. The actual amounts of foodstuffs required. Relation of nutritive value to cost of foods. The advantages of simplicity in diet. A sample dietary for a man of 70 kilograms body-weight. A new method of indicating food values. Moderation in the daily dietary leads toward vegetable foods. The experiments of Dr. Neumann. The value of fruits as food. The merits of animal and vegetable proteids considered in relation to the bacterial processes in the intestine. A notable case of simplicity in diet. Intelligent modification of diet to the temporary needs of the body. Diet in summer and winter contrasted. Value of greater protection to the kidneys. Conclusion.
Knowledge has value in proportion to the benefit it confers, directly or indirectly, on the human race. Every new scientific fact or principle brought to light promises help in the understanding of Nature’s laws, and when rightly interpreted and properly applied is sure to aid in the advancement and prosperity of the individual and of the community. Proper methods of living, economical adjustment of the intake to the varying needs of the body, avoidance of excessive waste of foodstuffs and of energy, are all desirable precepts, which rational people presumably are inclined to follow so far as their knowledge and understanding of the subject will permit. Here, as elsewhere, false teaching may be exceedingly mischievous and lead to costly errors; while blind reliance upon customs, instinct, and superstitions is hardly in keeping with twentieth-century progress.
Modern scientific methods should give us help in dietetics, as in other branches of hygiene and practical medicine. A few short years ago, diphtheria was a scourge which brought misery to many a home, for there was at hand no adequate means of combating the disease; but scientific research has given us new light, and placed at our command a weapon of inestimable value. Do we hesitate to use it when the occasion arises, because it happens to be out of keeping with old-time customs and traditions? No, we recognize the possibility of help, and as the need is urgent we turn to it quickly, with hope and thankfulness that scientific progress has opened up a pathway of escape from a threatened calamity.
Not many years ago we drank freely of such water as was at hand, without realization of danger from bacteria or disease germs, looking on epidemics of typhoid fever perhaps as a visitation of Divine Providence, in punishment of our many sins and to be borne meekly and with resignation. But all this has changed through the researches of bacteriologists and chemists; scientific facts of the utmost importance have been clearly established; a classification of water-borne diseases has been adopted, and we realize fully that diseases of this order can be kept from our doors by proper precautions applied to our water supply. To-day, epidemics of typhoid fever are traceable solely to the ignorance or carelessness of the individual or of the commonwealth, and the exemption which we of the present generation have from this class of diseases is directly due to the application of precautionary measures based on the information furnished by scientific investigation. It is proper for us to use caution in the acceptance of new ideas, but not that form of caution which refuses change on the ground that what has been is sufficiently good for the present and the future. The point of view is ever changing with advance of knowledge, and it is not profitable to exclude opportunities for improvement in personal hygiene and general good health, any more than in other matters that affect the prosperity of the individual or the community.
Dietary habits should be brought into conformity with the true needs of the body. Excessive consumption of proteid food, especially, should be avoided on the ground that it is not only unnecessary and wasteful, but is liable to bring penalties of its own, most undesirable and wholly uncalled for. We may, perhaps, accept these statements at their full value, and yet have a shadow of doubt in our minds as to whether, after all, dietary customs do not harmonize sufficiently at least with true nutritive requirements. All the data that we have presented in the preceding chapters, however, have seemingly given a positive answer to such doubts, and indicate quite clearly that the results of scientific study are opposed to the prevailing dietary standards, especially as regards proteid food. As the celebrated physiologist Bunge has expressed it, “The necessity for a daily consumption of 100 grams of proteid is incomprehensible, so long as we do not know of any function of the body in the performance of which the chemical potential energies of the destroyed proteid are used up.”
Perfectly trustworthy evidence is at hand showing that the needs of the body for potential energy can be fully met, and indeed are more advantageously met, by the non-nitrogenous foods, carbohydrates and fats. The energy of muscle work, as we have seen, comes preferably from the breaking down of non-nitrogenous material, so that there is no special call for proteid in connection with increased muscular activity. In fact, it would appear that the need for proteid food by man is limited to the requirements of growth and development, reinforced by the amount called for in that form of tissue exchange which we have emphasized under the term “endogenous proteid metabolism,” or true tissue metabolism. To be sure, there must be a certain reserve of proteid, available in case of emergency, but this is easily established without resorting to excessive feeding.
The peculiar position which proteid foods occupy in man’s dietary naturally make them the central figure, around which the other foods are grouped. No other form of food can take the place of proteid; a certain amount is needed each day to make good the loss of tissue material broken down in endogenous katabolism, and consequently our choice and combination of the varied articles of diet made use of should be regulated by the amount of proteid they contain. But while proteid foods occupy this commanding position, it is not necessary or desirable that they should exceed the other foodstuffs in amount, or indeed approach them in quantity. We must be ever mindful of the fact, so many times expressed, that proteid does not undergo complete oxidation in the body to simple gaseous products like the non-nitrogenous foods, but that there is left behind a residue of non-combustible matter—solid oxidation products—which are not so easily disposed of. In the forceful language of another, “The combustion of proteid within the organism yields a solid ash which must be raked down by the liver and thrown out by the kidneys. Now when this task gets to be over-laborious, the laborers are likely to go on strike. The grate, then, is not properly raked; clinkers form, and slowly the smothered fire glows dull and dies” (Curtis).
Even though no such dire fate overtakes one, the penalties of excessive proteid consumption are found in many ills, for which perhaps the victim seeks in vain a logical explanation; gastro-intestinal disturbance, indigestion, intestinal toxæmia, liver troubles, bilious attacks, gout, rheumatism, to say nothing of many other ailments, some more and some less serious, are associated with the habitual overeating of proteid food. But excessive food consumption is by no means confined to the proteid foodstuffs; general overfeeding is a widespread evil, the marks of which are to be detected on all sides, and in no uncertain fashion. One of the most common signs of excessive food consumption is the tendency toward obesity, a condition which is distinctly undesirable and may prove decidedly injurious. Undue accumulation of fat is not only a mechanical obstacle to the proper activity of the body as a whole, but it interferes with the freedom of movement of such muscular organs as the heart and stomach, thereby interposing obstacles to the normal action of these structures. Further, whenever undue fat formation is going on in the body, there is the ever present danger that the lifeless fat may replace the living protoplasm of the tissue cells and so give rise to a condition known as “fatty degeneration.” While a superabundance of fat in the body is a sure telltale of overeating, the absence of obesity is by no means an indication that excess of food is being avoided. There is here, in man as in animal kind, much idiosyncrasy; some persons, especially those endowed with a long and large frame, tend to keep thin even though they eat excessively, while others grow fat much more readily. As a well-known physician has expressed it, “In the one case, the subject burns, instantly and mercilessly, every stick of fuel delivered at his door, whether or not he needs the resulting hot fire roaring within, while the other, miser-like, hoards the rest in vast piles, filling the house from cellar to garret.”
Temperance in diet, like temperance in other matters, leads to good results, and our physiological evidence points out plainly, like a signpost all can read, that there is no demand on the part of the body for such quantities of food as custom and habit call for. Healthfulness and longevity are the prizes awarded for the successful pursuance of a temperate life, modelled in conformity with Nature’s laws. Intemperance, on the other hand, in diet as in other matters, is equally liable to be followed by disaster. A physician of many years’ experience, with opportunities for observation among different classes of people, has written, “that overeating tends to shrink the span of life in proportion as it expands the liver is demonstrable both directly and indirectly. Let any actuary of life-insurance be asked his experience with heavy-weight risks, where the waist measures more than the chest, and the long-drawn face of the businessman, at memory of lost dollars, will make answer without need of words. Then let be noted the physique of the blessed ones that attain to green old age, and, in nine cases out of ten, spry old boys—no disparagement, but all honor in the phrase—will be found to be modelled after the type of octogenarian Bryant or nonogenarian Bancroft—the whitefaced, wiry, and spare, as contrasted with the red-faced, the pursy, and the stout. It is true, as has already been mentioned, that in old age much of an adventitious obesity is absorbed and disappears, but the Bryant-Bancroft type is that of a subject who never has been fat at all. And just such is preëminently the type that rides easily past the fourscore mark, reins well in hand, and good for many another lap in the race of life.”[75]
With these thoughts before us, we may consider briefly just what is involved in these new dietary standards that aim to conform more closely with actual body needs. Referring at first to proteid food, it may be wise to again emphasize the fact that the weight of the body, i. e., the weight of the proteid-containing tissues, as contrasted with excessive fat accumulation, is one of the important factors not to be overlooked when determining the dietary needs of a given individual. As must be perfectly clear, from all that has been said, the man of 170 pounds’ body-weight has more proteid tissue to nourish than the man of 130 pounds’ weight, and consequently what will satisfy the requirements of the latter individual will not suffice for the former. We must understand distinctly that no general statement can be made applicable to mankind at large, but due consideration must be given to the size and weight of the individual structure. We have found that the average need for proteid food by adults is fully met by a daily metabolism equal to an exchange of 0.12 gram of nitrogen per kilogram of body-weight. This means a katabolism of three-fourths of a gram of proteid matter daily, per kilogram.
Remembering, however, that the intake of proteid food must be somewhat in excess of the actual proteid katabolism, since not all of the proteid of the food is available, and as this is a variable amount depending upon the proportion of animal and vegetable foods with their different degrees of digestibility and availability, we may place the required intake of proteid at 0.85 gram per kilogram of body-weight, still keeping to maximum figures for safety’s sake. Hence, for a man weighing 70 kilograms or 154 pounds, there would be required daily 59.5 grams—say 60 grams—of proteid food to meet the needs of the body. These are perfectly trustworthy figures, with a reasonable margin of safety, and carrying perfect assurance of being really more than sufficient to meet the true wants of the body; adequate to supply all physiological demands for reserve proteid, and able to cope with the erratic requirements of personal idiosyncrasies. It will be observed that such an intake of proteid food daily is equal to one-half the Voit standard for a man of this weight, while it is still further below the Atwater standard and far below the common practices of the majority of mankind in Europe and America, as indicated by the published dietary studies.
It may not be out of place to state at this point that in the writer’s opinion the use of the terms “standard diet” and “dietary standards,” etc., is objectionable, since such usage seems to demand a certain degree of definiteness in the daily diet for which there is no justification. As in the use of the term “normal diet,” there is danger of misinterpretation, and of the assumption that dietary habits should be regulated strictly in accord with certain set principles. This I believe to be altogether wrong; there should be, on the contrary, full latitude for individual freedom, but freedom governed by an intelligence that appreciates the significance of scientific fact and is willing to mould custom and habit into accord with them. What is needed to-day is not so much an acceptance of the view that man requires daily 0.85 gram of proteid per kilogram of body-weight, as a full appreciation of the general principle, which our definite figures have helped to work out, that the requirements of the body for proteid food are far below the customary habits of mankind, and that there is both economy and gain in various directions to be derived by following the general precepts which this view leads to. In other words, there is no advantage, but, on the contrary, much bother and worriment, in attempting to follow out in practice the details of our more or less exact physiological experiments.
The general teaching which they afford, however, can be adopted and put in practice in our daily lives, without striving to follow too closely the so-called standards which our experiments have led to. Again, the sample dietaries adopted in our experiments have no special virtue, aside from the general principle they teach that simple foods are quite adequate for the nourishment of the body, and that the amount of nitrogen or proteid they contain was sufficient to meet the demands of the particular individuals consuming it. Broadening intelligence on matters of food composition is called for on all sides, and as this is acquired together with due appreciation of the relative nutritive values of proteid, fat, and carbohydrate, there is placed at our command the power of intelligent discrimination, with the ability to apply the principles set forth in our own way, in harmony with personal likes and dislikes.
To the majority of us, not very familiar with the percentage composition of ordinary food materials, and unaccustomed to the weighing of food in grams, the figures given from time to time may have failed to convey a very definite impression regarding the actual amounts of the various foods made use of. Further, our ideas concerning the bulk of many of the common articles of food necessary to furnish the 60 grams of proteid required daily by a man of 70 kilograms body-weight may be somewhat hazy. The following table, however, will be of service in this direction:
SIXTY GRAMS OF PROTEID ARE CONTAINED IN
Fuel Value* | ||
| One-half pound fresh lean beef, loin | 308 | calories |
| Nine hens’ eggs | 720 | |
| Four-fifths pound sweetbread | 660 | |
| Three-fourths pound fresh liver | 432 | |
| Seven-eighths pound lean smoked bacon | 1820 | |
| Three-fourths pound halibut steak | 423 | |
| One-half pound salt codfish, boneless | 245 | |
| Two-and one-fifth pounds oysters, solid | 506 | |
| One-half pound American pale cheese | 1027 | |
| Four pounds whole milk (two quarts) | 1300 | |
| Five-sixths pound uncooked oatmeal | 1550 | |
| One and one-fourth pounds shredded wheat | 2125 | |
| One pound uncooked macaroni | 1665 | |
| One and one-third pounds white wheat bread | 1520 | |
| One and one-fourth pounds crackers | 2381 | |
| One and two-thirds pounds flaked rice | 2807 | |
| Three-fifths pound dried beans | 963 | |
| One and seven-eighths pounds baked beans | 1125 | |
| One-half pound dried peas | 827 | |
| One and eleven-twelfths pounds potato chips | 5128 | |
| Two-thirds pound almonds | 2020 | |
| Two-fifths pound pine nuts, pignolias | 1138 | |
| One and two-fifths pounds peanuts | 3584 | |
| Ten pounds bananas, edible portion | 4600 | |
| Ten pounds grapes | 4500 | |
| Eleven pounds lettuce | 990 | |
| Fifteen pounds prunes | 5550 | |
| Thirty-three pounds apples | 9570 | |
* Fuel value of the quantity needed to furnish the sixty grams of proteid.
The figures in this table are instructive in many ways. First, it is to be noted that the daily proteid requirement of sixty grams can be obtained from one-half pound of lean meat (uncooked), of which the loin steak is a type. Subject to some variations in content of water, an equivalent weight of lean flesh of any variety, lamb, veal, poultry, etc., will furnish approximately the same amount of proteid. With fish, such as halibut steak, and with liver, three-quarters of a pound are required; while with sweetbreads, four-fifths of a pound are needed to furnish the requisite amount of proteid. Of salt codfish, one-half pound will provide the same amount of proteid as an equivalent weight of fresh beef; while with lean smoked bacon the amount rises to seven-eighths of a pound. Among the vegetable products, it is to be observed that dried peas and beans, almonds and pine nuts, are as rich in proteid as the above-mentioned animal foods, essentially the same weights being called for to provide the daily requirement of proteid. The same is true of cheese, the variety designated having such a composition that one-half pound is the equivalent, so far as the content of proteid is concerned, of a like amount of fresh beef. We must not be unmindful of the fact previously mentioned, however, that there are differences in digestibility among these various foodstuffs which tend to lower somewhat the availability of the vegetable products, also of the cheese, thereby necessitating a slight increase in the amount of these foods required to equal the value to the body of lean meat.
Secondly, passing to the other extreme in our list, we find indicated types of foods exceedingly poor in proteid, such as the fruits; notably, bananas, grapes, prunes, apples, etc., also lettuce, and in less degree potatoes. These are the kinds of food that may legitimately attract by their palatability, but do not add materially to our intake of proteid even when consumed in relatively large amounts. Thirdly, we see clearly indicated a radical difference between the animal foods and those of vegetable origin, in that with the former the fuel value of the quantity necessary to furnish the sixty grams of proteid is very small, as compared with a like amount of the average vegetable product. One-half pound of lean meat, for example, with its 60 grams of proteid, has a fuel value of only 308 calories, while two-thirds of a pound of almonds has a fuel value of 2020 calories, and one-half pound of dried peas 827 calories. Naturally, this is mainly a question of the proportion of fat or oil present. With fat meat, as in bacon, the calorific value rises in proportion to increase in the amount of fat, the proteid decreasing in greater or less measure.
The main point to be emphasized in this connection, however, is that a high proteid animal food, like lean meat, eggs, fish, etc., obviously cannot alone serve as an advantageous food for man. We see at once the philosophy of a mixed diet. Let us assume that our average man of 70 kilograms body-weight needs daily 2800 calories. On this assumption, if he were to depend entirely upon lean beef for his sustenance, he would require daily four and a half pounds of such meat, which amount would furnish nine times the quantity of proteid needed by his system. The same would be more or less true of other kindred animal products. On the other hand, certain vegetable foods on our list, such as flaked rice, crackers, and shredded wheat, contain proteid, with carbohydrate and fat, in such proportion that the energy requirement would be met essentially by the same quantity as served to furnish the necessary proteid. Passing to the other extreme among the vegetable products, as in potatoes and bananas, for example, we find fuel value predominating largely over proteid content. The ideal diet, however, is found in a judicious admixture of foodstuffs of both animal and vegetable origin. Wheat bread, reinforced by a little butter or fat bacon to add to its calorific value, shredded wheat with rich cream, crackers with cheese, bread and milk, eggs with bacon, meat with potatoes, etc.; the common, every-day household admixtures, provide combinations which can easily be made to accord with true physiological requirements. The same may be equally true of the more complicated dishes evolved by the high art of modern cookery.
Lastly, our table throws light upon certain questions of household economy. The cost of foods is regulated mainly not by the value of the nutrients contained therein, but by other factors of quite a different nature. Relationship between supply and demand naturally counts here as in other directions, but our demand is liable to be based not upon food values, but rather upon delicacy of flavor, palatability, and other kindred fancies, some real and some imaginary. Ordinary crackers can be purchased for ten cents a pound, but if we desire a little stronger flavor of salt and a special box to hold them, we pay eighteen cents a pound. Rolled very thin and thus made more delicate, they cost twenty-five cents, while sold under a special name and perhaps tied with a blue ribbon they cost thirty-five cents a pound. Their nutritive value per pound is the same in all cases, but we pay something for the increased labor of preparation and a good deal for the added attractiveness to eye and palate. We pay twenty-two cents a pound for round steak, thirty-two cents for loin steak, and seventy-five cents a pound for sweetbreads, the high price of the latter being regulated by the relative scarcity of the article and not by its food value. As our table indicates, the real value of sweetbread as a source of proteid is only a little more than half that of lean beef. Its fuel value, however, is somewhat more than that of beef, but a little fat added to the latter will more than compensate and at a trifling cost. When we can afford it, we pay the increased price for sweetbreads simply because their delicacy and flavor are attractive to us. We should not do it under the mistaken idea that we are indulging in a highly nutritive article of food, for as a matter of fact it is not only less nutritive than a corresponding weight of lean beef, but in addition it possesses certain qualities, in its high purin-content, that are a menace to good health if indulged in too freely.
Where expense must be carefully guarded, or where the condition of the family purse is such that conflicting demands must be intelligently considered in order to insure wise expenditure and the greatest permanent good of the many, it is well to remember that price is no guarantee whatever of real nutritive value. Two quarts of milk will furnish half the daily fuel requirement of our average man and the entire proteid requirement, while its cost is only sixteen cents. Reinforced by a pound loaf of wheat bread, the energy requirement for the day would be fully met, with surplus nitrogen to store up for future needs, and at an additional cost of only ten cents. A mixture in this proportion, however, would not be strictly physiological, since it is wasteful of proteid, but it may serve to illustrate the point. A better illustration is found in an admixture, quite adequate to supply the daily needs of our average man, both for proteid and energy, composed of one-quarter of a pound of lean beef, two-thirds of a pound of bread, and half a pound of butter, and at a total cost not to exceed thirty cents. The contrast of such prices with what is so commonly paid for table delicacies is somewhat striking; it could be made still more so by drawing upon many common vegetable foods, rich alike in proteid and in fuel value, the cost of which is even less than the simple food mixtures just referred to. It is not necessary, however, to enlarge upon this question; it is sufficient to merely emphasize the fact that the exaggerated demand of our present generation for dietetic luxuries is leading us far away from the proverbially simple life of our forefathers, and without adding in any way to the effectiveness of the daily diet. On the contrary, it is in part responsible for the high proteid consumption of the present day, with its attendant evils, and involves a large and unnecessary expenditure without adequate return. The wants of the body for food are far more advantageously met by a simple dietary, moderate in amount and at an expense comparatively slight.
A recent writer,[76] in the “British Medical Journal,” a practitioner of medicine in the Highlands of Scotland, has said that these are “facts of common experience in the Highlands of Scotland, and probably among the peasantry of other countries also, where the old beliefs and customs have not too readily given way to the luxuries of civilization. Oatmeal in one form or another is a daily ingredient in the diet of a Highland peasant. The potato also is a staple food, and is consumed in large quantities with salt herring or other fish, and perhaps in some cases salt mutton or pork. Milk and eggs are used by most. The growing consumption of tea, however, and the increasing relish for sweets, candy, pastry, and biscuits, threaten to destroy the old way of living. A typical day’s diet for a crofter or fisherman who still believes in the traditional diet would be somewhat like this:
Breakfast.—Oatmeal porridge or brose with milk; bread, butter, and tea.
Dinner.—Potatoes galore and herrings, or other salt fish.
Supper.—Porridge and milk, or oat bread and cheese, and tea.
“I have often been assured by shepherds that they could work all day ‘on the hill’ after a breakfast of oatmeal brose and milk, without fatigue and without feeling hungry, returning in the evening to partake of a dish of broth, potatoes, and salt mutton. In these diets, proteid forms a very small proportion, and yet a hardier race than these shepherds and fishermen cannot be found.” It should be added that “brose” consists of a few handfuls of oatmeal, to which is added boiling water, the mixture being stirred vigorously and placed for a few minutes near the fire. It is then eaten with milk, or better, with cream. In the absence of positive data, it can only be asserted that the above dietary stands for simplicity and frugality. Its proteid-content may be low, but the amount of proteid taken per day by these Highlanders will obviously depend upon the quantity of food consumed. Oatmeal is fairly rich in proteid, and it is quite conceivable that the amount eaten daily may be such as to result in a high proteid exchange.
It will be profitable for us to gain, if possible, a fairly clear idea of the quantities of food requisite for our average man of 70 kilograms body-weight; i. e., the amounts necessary to provide 60 grams of proteid and 2800 calories. With this end in view, we may outline a simple dietary, expressed in terms that will convey a clear impression, showing what may be eaten without overstepping the required limits of proteid or total calories:
BREAKFAST | |||
Proteid | Calories | ||
| One shredded wheat biscuit 30 grams | 3.15 | grams | 106 |
| One teacup of cream 120 grams | 3.12 | 206 | |
| One German water roll 57 grams | 5.07 | 165 | |
| Two one-inch cubes of butter 38 grams | 0.38 | 284 | |
| Three-fourths cup of coffee 100 grams | 0.26 | . . . | |
| One-fourth teacup of cream 30 grams | 0.78 | 51 | |
| One lump of sugar 10 grams | . . . | 88 | |
12.76 | 850 | ||
LUNCH | |||
Proteid | Calories | ||
| One teacup homemade chicken soup 144 grams | 5.25 | grams | 60 |
| One Parker-house roll 38 grams | 3.38 | 110 | |
| Two one-inch cubes of butter 38 grams | 0.38 | 284 | |
| One slice lean bacon 10 grams | 2.14 | 65 | |
| One small baked potato 2 ounces, 60 grams | 1.53 | 55 | |
| One rice croquette 90 grams | 3.42 | 150 | |
| Two ounces maple syrup 60 grams | . . . | 166 | |
| One cup of tea with one slice lemon | . . . | . . | |
| One lump of sugar 10 grams | . . . | 38 | |
16.10 | 928 | ||
DINNER | |||
Proteid | Calories | ||
| One teacup cream of corn soup 130 grams | 3.25 | grams | 72 |
| One Parker-house roll 38 grams | 3.38 | 110 | |
| One-inch cube of butter 19 grams | 0.19 | 142 | |
| One small lamb chop, broiled lean meat, 30 grams | 8.51 | 92 | |
| One teacup of mashed potato 167 grams | 3.34 | 175 | |
| Apple-celery lettuce salad with mayonnaise dressing 50 grams | 0.62 | 75 | |
| One Boston cracker, split 2 inches diameter, 12 grams | 1.32 | 47 | |
| One-half inch cube American cheese 12 grams | 3.35 | 50 | |
| One-half teacup of bread pudding 85 grams | 5.25 | 150 | |
| One demi-tasse coffee | . . . | . . | |
| One lump of sugar 10 grams | . . . | 38 | |
29.21 | 951 |
BREAKFAST | |||
Proteid | Calories | ||
| One shredded wheat biscuit 30 grams | 3.15 | grams | 106 |
| One teacup of cream 120 grams | 3.12 | 206 | |
| One German water roll 57 grams | 5.07 | 165 | |
| Two one-inch cubes of butter 38 grams | 0.38 | 284 | |
| Three-fourths cup of coffee 100 grams | 0.26 | . . . | |
| One-fourth teacup of cream 30 grams | 0.78 | 51 | |
| One lump of sugar 10 grams | . . . | 88 | |
12.76 | 850 | ||
LUNCH | |||
Proteid | Calories | ||
| One teacup homemade chicken soup 144 grams | 5.25 | grams | 60 |
| One Parker-house roll 38 grams | 3.38 | 110 | |
| Two one-inch cubes of butter 38 grams | 0.38 | 284 | |
| One slice lean bacon 10 grams | 2.14 | 65 | |
| One small baked potato 2 ounces, 60 grams | 1.53 | 55 | |
| One rice croquette 90 grams | 3.42 | 150 | |
| Two ounces maple syrup 60 grams | . . . | 166 | |
| One cup of tea with one slice lemon | . . . | . . | |
| One lump of sugar 10 grams | . . . | 38 | |
16.10 | 928 |
DINNER | |||
Proteid | Calories | ||
| One teacup cream of corn soup 130 grams | 3.25 | grams | 72 |
| One Parker-house roll 38 grams | 3.38 | 110 | |
| One-inch cube of butter 19 grams | 0.19 | 142 | |
| One small lamb chop, broiled lean meat, 30 grams | 8.51 | 92 | |
| One teacup of mashed potato 167 grams | 3.34 | 175 | |
| Apple-celery lettuce salad with mayonnaise dressing 50 grams | 0.62 | 75 | |
| One Boston cracker, split 2 inches diameter, 12 grams | 1.32 | 47 | |
| One-half inch cube American cheese 12 grams | 3.35 | 50 | |
| One-half teacup of bread pudding 85 grams | 5.25 | 150 | |
| One demi-tasse coffee | . . . | . . | |
| One lump of sugar 10 grams | . . . | 38 | |
29.21 | 951 |
The grand totals for the day, with this dietary, amount to 58.07 grams of proteid and 2729 calories. It is of course understood that these figures are to be considered as only approximately correct, but the illustration will suffice, perhaps, to give a clearer understanding of the actual quantities of food involved in a daily ration approaching the requirements for a man of 70 kilograms body-weight. Further, there may be suggested by the figures given for proteid and fuel value of the different quantities of foods, a clearer conception of how much given dietary articles count for in swelling the total values of a day’s intake. Moreover, it is easy to see how the diet can be added to or modified in a given direction. If a little more proteid is desired without changing materially the fuel value of the food a boiled egg can be added to the breakfast, for example. An average-sized egg (of 53 grams) contains 6.9 grams of proteid, while it will increase the fuel value of the food by only 80 calories. Or, if more vegetable proteid is wished for, a soup of split-peas can be introduced, without changing in any degree the calorific value of the diet. Thus, one teacup of split-pea soup (144 grams) contains 8.64 grams of proteid, while the fuel value of this quantity may be only 94 calories. The addition of one banana (160 grams) will increase fuel value 153 calories, but will add only 2.28 grams of proteid. If it is desired to increase fuel value without change in the proteid-content of the food, recourse can always be had to butter, fat of meat, additional oil in salads, or to syrup and sugar.
Such a menu as is roughly outlined, however, has perhaps special value in emphasizing how largely the proteid intake is increased by foods other than meats, and which are not conspicuously rich in proteid matter. All wheat products, for example, while abounding in starch, still show a large proportion of proteid. Thus, shredded wheat biscuit (1 ounce), which is a type of many kindred wheat preparations, from bread and biscuit to the various so-called breakfast foods, yields about 3 grams of proteid per ounce and approximately 100 calories. Even potato, which is conspicuously a carbohydrate food owing to its large content of starch, yields of nitrogen the equivalent of at least three-fourths of a gram of proteid per ounce. If larger volume is desired without much increase in real food value, there are always available green foods, such as lettuce, celery, greens of various sorts, fruits, such as apples, grapes, oranges, etc. Too great reliance on meats as a type of concentrated food, on the other hand, augments largely the intake of proteid, and adds a relatively small amount to the fuel value of the day’s ration.
An ingenious method of indicating food values, which promises to be of service in sanatoria and under other conditions where it is desirable to record or correct the diet of a large number of persons, has been devised recently by Professor Fisher.[77] The method aims to save labor, and is likewise designed to visualize the magnitude and proportions of the diet. The food is measured by calories instead of by weight, a “standard portion” of 100 large calories being the unit made use of. In carrying out the method, foods are served at table in “standard portions,” or multiples thereof. In the words of Fisher, the amount of milk served, for example, “instead of being a whole number of ounces, should be 4.9 ounces—the amount that contains 100 calories. This ‘standard portion’ constitutes about two-thirds of an ordinary glass of milk. Of the 100 calories which it contains 19 will be in the form of proteid, 52 in fat, and 29 in carbohydrate.” In the carrying out of this plan, it is evident that the weight of any food yielding 100 calories becomes a measure of the degree of concentration. From the standpoint of fuel value, olive oil is probably one of the most concentrated of foods, approximately one-third of an ounce containing 100 calories. The following table, taken from Fisher’s description of his method, will serve to show the amounts of several foods constituting a “standard portion,” and also the number of calories in the form of proteid, fat, and carbohydrate:
| Name of Food and “Portion” roughly estimated. | Weight contain- ing 100 Calories. | Proteid. | Fat. | Carbo- hydrate. | Total. | |
|---|---|---|---|---|---|---|
| ounces | grams | calories | calories | calories | calories | |
| Almonds, a dozen | 0.53 | 15 | 13.0 | 77.0 | 10 | 100 |
| Bananas, one large | 3.50 | 98 | 5.0 | 5.0 | 90 | 100 |
| Bread, a large slice | 1.30 | 37 | 13.0 | 6.0 | 81 | 100 |
| Butter, an ordinary pat | 0.44 | 13 | 0.5 | 99.5 | . . | 100 |
| Eggs, one large | 2.10 | 60 | 32.0 | 68.0 | . . | 100 |
| Oysters, a dozen | 6.80 | 190 | 49.0 | 22.0 | 29 | 100 |
| Potatoes, one | 3.60 | 100 | 10.0 | 1.0 | 89 | 100 |
| Whole milk, two-thirds glass | 4.90 | 140 | 19.0 | 52.0 | 29 | 100 |
| Beef sirloin, a small piece | 1.40 | 40 | 31.0 | 69.0 | . . | 100 |
| Sugar, five teaspoons | 0.86 | 24 | . . . . | . . . . | 100 | 100 |
Obviously, to make use of the “calories per cent” method a table such as the above, covering all common foodstuffs and showing the weight of each food constituting a standard portion, together with the calories of proteid, fat, and carbohydrate in this portion, is necessary. The chief advantage of the method, however, is that it lends itself readily to geometrical representation and affords an easy means of determining the constituents of combinations of different foods by use of a simple mechanism, for a description of which reference must be made to the original paper.
Any attempt to follow a daily routine which accords with the true needs of the body leads necessarily toward foods derived from the plant kingdom, with the adoption of simple dietary habits, and with greater freedom from the exciting influence of the richer animal foods. There is, however, virtue in a simple dietary that appeals and satisfies, and in so doing testifies to the completeness with which it meets the physiological requirements of the body. A physician,[78] writing in the “British Medical Journal,” says: “I determined to give the minimum-of-proteid diet a fair trial in my own case. The result was that I was relieved of a life-long tendency to acid dyspepsia and occasional sick headache; my fitness for work, my appetite and relish for food, were increased, without any diminution, but rather a slight increase, in my weight. My practice extends over a wide area of rough mountainous country involving long journeys on cycle, on foot, driving, and in open boats, in fair and foul weather. The muscular exertion and endurance necessary for the work would seem to require a large proportion of proteid and a generous diet altogether, but since I began to experiment I have suffered less than formerly from fatigue, and seem to eat in all a smaller quantity of food. My diet consists of:
Breakfast, 8.30 A.M.—Oatmeal cakes, bread and butter, about 1 cubic inch of cheese or bloater paste, marmalade, and one breakfast cup of tea.
Lunch, 1.30 P.M.—Same as breakfast, with occasionally a boiled egg, and sometimes coffee instead of tea.
Dinner, 7 P.M.—Thick soup containing vegetables, with bread, followed by suet pudding or fruit tart; or vegetable stew, containing 2 or 3 ounces of meat, with boiled potatoes, followed by milk pudding and jam, and occasionally a cup of black coffee.”
This statement of personal experience is in close accord with statements that have come to the writer in hundreds of letters during the past two or three years, from persons who have for some reason chosen to follow a more abstemious mode of life. Such testimony has a certain measure of value in that it offers corroborative evidence of the beneficial effects of a moderate diet, more closely in accord with the actual demands of the body for food. It does not, however, carry quite that degree of assurance that scientific evidence, gathered by careful observers and controlled by weights and measures that hold the imagination in check, affords; and so we may turn to a different type of testimony, presented in an elaborate research by Dr. Neumann,[79] of the Hygienic Institute at Kiel, an experiment on himself extending through a total of 746 days.
The experiment was divided into three periods. In the first period of ten months the subject, with a body-weight of 66.5 kilograms, consumed daily on an average the amounts of food indicated in the following table. In this same table are also included the daily values, based on the preceding data, for a body-weight of 70 kilograms. Thirdly, the table likewise shows the amounts of utilizable food contained in the foodstuffs actually eaten, on the basis of 70 kilos body-weight.
AVERAGE DAILY FOOD FOR TEN MONTHS
| Actually consumed by the Subject, 66.5 Kilos | Calculated for a Body-weight of 70 Kilos | Utilizable Food for a Body-weight of 70 Kilos | |
|---|---|---|---|
| Proteid | 66.1 grams | 69.1 grams | 57.3 grams |
| Fat | 83.5 grams | 90.2 grams | 81.2 grams |
| Carbohydrate | 230.0 grams | 242.0 grams | 225.0 grams |
| Alcohol | 43.7 grams | 45.6 grams | 41.0 grams |
| Fuel value | 2309 calories | 2427 calories | 2199 calories |
During this period of ten months, the body-weight of the subject remained practically constant, or indeed showed a slight gain up to 67 kilograms. All the functions of the body, and the general condition of good health, were in no wise impaired; so that in the words of the subject, the amount of food eaten must have been sufficient for the needs of the body. Somewhat striking is the fact that of the 2309 calories in the daily food, more than one-fourth was derived from the beer consumed daily (1200 c.c.). Also noticeable is the relatively small amount of carbohydrate taken daily, only about one-half the quantity designated by Voit as the average requirement of German laborers. Finally, it is to be observed that during this period of ten months, the daily consumption of food as calculated for a man of 70 kilograms body-weight, based on the actual food consumption of the subject with a weight of 66.5 kilos, was not widely different from our own statement of 60 grams of proteid and 2800 calories. The tendency, however, in Dr. Neumann’s experiment was toward lower fuel values and somewhat higher proteid consumption.
In a second period of 50 days, with a slightly larger daily intake, Dr. Neumann observed that his body was laying by nitrogen, i. e., storing up proteid on a daily diet of 76.5 grams of proteid and with sufficient fat and carbohydrate to furnish a total fuel value of 2658 calories. In the final period of 8 months, the following data were obtained:
AVERAGE DAILY FOOD FOR EIGHT MONTHS
| Actually consumed by the Subject, 71.5 Kilos. | Calculated for a Body-Weight of 70 Kilos. | Utilizable Food for a Body-Weight of 70 Kilos. | |
|---|---|---|---|
| Proteid | 76.2 grams | 74.0 grams | 61.4 grams |
| Fat | 109.0 grams | 106.1 grams | 95.5 grams |
| Carbohydrate | 168.9 grams | 164.2 grams | 152.7 grams |
| Alcohol | 5.5 grams | 5.3 grams | 4.7 grams |
| Fuel value | 2057 calories | 1999 calories | 1766 calories |
During this period, it is to be noted that the fuel value of the day’s food averaged only 2057 calories, which for a body-weight of 70 kilograms would amount to less than 2000 calories. The proteid consumption, however, was larger than we have found to be necessary for a man of the above weight. Still, the facts are in harmony with the general principle that there is no necessity for a daily intake of food such as common usage dictates, there being obviously a wide difference between a minimal daily consumption of 118 grams of proteid and 3000 or more calories, such as is assumed to be needed by a man of 70 kilos, and 74 grams of proteid with 1999 calories. Under the latter conditions, the subject gained a kilogram in weight during the eight months, while the establishment of nitrogen equilibrium testifies to the now generally accepted view that it is quite possible for the body to establish nitrogen equilibrium at different levels, i. e., with different quantities of proteid food and different fuel values.
The diet made use of by Neumann was a mixed one, containing a great variety of animal and vegetable foods, but withal simple and moderate in quantity. Calculated per kilogram of body-weight, the average consumption of food material per day during the three periods was as indicated in the following table:
DAILY FOOD CONSUMPTION PER KILOGRAM OF WEIGHT
| Proteid. | Fat. | Carbohydrate. | Alcohol. | Calories | |
|---|---|---|---|---|---|
| grams | grams | grams | grams | ||
| First Period | 0.99 | 1.3 | 34.5 | 0.56 | 34.7 |
| Second Period | 1.10 | 2.3 | 33.4 | . . | 59.7 |
| Third Period | 1.00 | 1.5 | 23.4 | 0.07 | 28.5 |
The average of daily food consumption for the total of 746 days was as follows: 74.2 grams proteid, 117 grams fat, 213 grams carbohydrate, and 2367 calories. On such a diet, during this long period, equilibrium was satisfactorily maintained, thereby furnishing additional evidence that quantities of food way below the so-called normal amounts are quite adequate to meet the needs of the body. There is no conflict whatever between these results and our own; they both point in the same general direction. Perhaps the one thing that needs to be again emphasized, however, in view of the low fuel values used by Neumann, is that while they proved quite adequate in his case, the demand in this direction is governed largely by the degree of bodily activity. In fact, Neumann’s results with fuel values are in perfect harmony with the data obtained by us with professional men, but the writer is inclined to believe that for the majority of mankind, with the varying degrees of activity and muscular exertion called for, a somewhat larger number of heat units is desirable, and indeed on many occasions demanded.
Still, it is perfectly obvious that custom has greatly exaggerated the fuel values required in ordinary muscular work, and such results as are here presented tend to emphasize the true relationship between actual requirements and fuel intake. Further, it must not be overlooked that the rate of proteid katabolism is governed in large measure by the amount of non-nitrogenous food, and consequently a too narrow margin in the consumption of the latter will obviously result in a higher rate of proteid exchange. We are inclined to the belief that a satisfactory degree of bodily efficiency is more liable to be maintained with a somewhat larger consumption of carbohydrate food, combined with a reduction in proteid food to a level nearer our own figures. It will be observed that the average amount of carbohydrate taken daily by Neumann, during the 746 days, was only 213 grams, while the daily consumption of fat averaged 117 grams. These figures are interesting and instructive in many ways, especially as indicating the ease with which the body accommodates itself to a relatively low intake of proteid food, combined with a small proportion of starches and sugars. This relationship between carbohydrate and fat might well occur at times as a natural result of personal taste, but as a general rule it is probably better, from the standpoint of digestibility and general availability, for the daily food to contain a larger proportion of carbohydrate.
Under this head, I would lay special stress upon the value to the body of the natural sugars as well as of starch. We are inclined to deprecate the widespread use of candy, especially among children, and there is no doubt that the too lavish use of sugar in such concentrated form does at times do harm; but when eaten as an integral part of the many available fruits its use cannot be too highly lauded, for both young and old. Oranges, grapes, prunes, dates, plums, and bananas are especially to be commended, and in lesser degree peaches, apricots, pears, apples, figs, strawberries, raspberries, and blueberries. In all of these fruits, it is the sugar especially that gives food value to the article, while the mild acids and other extractives, together with the water of the fruit, help in other ways in the maintenance of good health. Where personal taste and inclination are favorably disposed, the first six fruits named can be partaken of freely, and the diet of the young, especially, can be advantageously modified by the liberal use of such articles of food.
Of the other fruits, apples when thoroughly ripe are above reproach if properly masticated, but the raw fruit is somewhat indigestible when swallowed in too large pieces, and may cause trouble to a delicate stomach. A baked apple, on the other hand, is both savory and wholesome, and if served with sugar and cream, for example, constitutes a most healthful and satisfying article of food. Peaches, apricots, and strawberries as ripe fruits are likewise exceedingly valuable, but here personal idiosyncrasy frequently comes to the fore, especially with strawberries, and prohibits their free use. The peculiar acidity of these latter fruits is occasionally a source of trouble, which leads to their avoidance; but this is far less liable to happen with people living on a low proteid diet with its greater freedom from purin derivatives, or uric acid antecedents. Further, there is a tendency on the part of some individuals to suffer from acid fermentation with too liberal use of starches and sugar, but as a rule the advantages of ordinary starchy and natural sugar-containing foods cannot be overestimated. It is certainly wise to give them a conspicuous place in the daily dietary and to encourage their use, especially by children.
As has been stated in several connections, a diet which conforms to the true nutritive requirements of the body must necessarily lead toward vegetable foods. In no other satisfactory way can excess of proteid be avoided, and at the same time the proper calorific value be obtained. This, however, does not mean vegetarianism, but simply a greater reliance upon foods from the plant kingdom, with a corresponding diminution in the typical animal foods. This raises the question of the possible relation of diet to the bacterial processes of the intestine, knowing, as we do, that the latter are of primary importance in the causation of certain forms of auto-intoxication, etc. Recent studies have indicated that the bacterial flora of carnivorous animals is quite different from that of herbivorous animals, and this being so, it is easy to see how a predominance of vegetable or animal food may modify the bacterial conditions of the intestinal tract in man. Dr. Herter[80] has reported the presence in the intestines of cats, dogs, tigers, lion, and wolf of many spore-holding bacilli, as well as free spores and vegetative forms of anærobic organisms; some of which at least are decidedly pathogenic when injected into the subcutaneous connective tissue, leading to serious and even fatal results within twenty-four hours. With herbivorous animals, on the other hand, such as the buffalo, goat, horse, elephant, etc., the predominating organisms are of a different order from those found in the intestines of the carnivora; proving practically non-pathogenic, or only slightly so, when injected subcutaneously, and less disposed to produce putrefactive changes or other chemical decompositions.
In the words of Dr. Herter, “These differences in the appearance and behavior of the bacteria derived from typical carnivora and herbivora suggest that the habit of living upon a diet consisting exclusively of raw meat entails differences in the types of bacteria that characterize the contents of the large intestine. The occurrence of considerable numbers of spore-bearing organisms in the carnivora points to the presence of anærobic putrefactive forms in great numbers. The results of subcutaneous inoculations into guinea-pigs bear out this view and indicate that the numbers of organisms capable of producing a hemorrhagic œdema with tissue necrosis, with or without gas-production, are very considerable. . . . The observations recorded are of much interest in relation to the bacterial processes and nutrition of herbivorous as distinguished from carnivorous animals, and are significant furthermore for the interpretation of bacterial conditions found in man. The question arises whether the abundant use of meat over a long period of time may not favor the development of much larger numbers of spore-bearing putrefactive anærobes in the intestinal tract than would be the case were a different type of proteid substituted for meat.” While it may be said truly that observations of this character are as yet not sufficiently numerous or conclusive to warrant positive or sweeping statements, yet there is a suggestion here well worthy of thoughtful consideration in its general bearing on the nutrition of mankind.
Simplicity in diet, with or without complete abstinence from meat, is often resorted to as a means of relief from bodily ailments, and such cases sometimes afford striking illustrations of the adequacy and benefits of a relatively low intake of food. Cases of this sort, perhaps, are more frequently observed among elderly people, where the daily requirements are not so great as with younger and more active persons, but they offer evidence in support of our main thesis that dietary habits are no guarantee of bodily requirements. I have in mind the details of an exceedingly interesting case reported with much care by Dr. Fenger;[81] the case of a man who at 61 years of age, after a long period of poor health, brought himself quickly into a condition of sound health by a daily diet characterized by extreme simplicity and with an exceedingly low fuel value. The daily diet made use of during the fifteen years the subject was under examination consisted of the following articles:
1889–1892: 1 egg, 1 quart of oatmeal soup, 2 quarts of skim milk, 1 1/2 ounces of red wine, 1/4 ounce of sugar.
1892–1894: 2 eggs, 1 quart of oatmeal soup, 2 quarts of skim milk, 1 1/2 ounces of red wine, 1/4 ounce of sugar.
1894–1900: 3 eggs, 1 pint of oatmeal soup, 2 quarts of skim milk, 1 1/2 ounces of red wine, 1/4 ounce of sugar, 2 ounces of plum and raspberry juice.
1900–1903: 3 eggs, 1 pint of barley soup, 3 pints of sweet milk, 1 pint of buttermilk, 1 1/2 ounces of red wine, 1/4 ounce of sugar, 2 ounces of plum and raspberry juice.
It will be observed that during these fifteen years the subject partook of no meat whatever, and further, that the diet was wholly in fluid form. At the close of this long period, the subject, being then 75 years of age, was reported as well and in good health, with satisfactory physical condition for a person of his years. He was a man of small body-weight, only 42 kilograms, but during this period of voluntary restriction in diet, he suffered no loss. It is perhaps worthy of comment also that all through this lengthy period no salt was taken other than what was naturally present in the simple foods made use of. The point to attract our attention especially, however, is that for fifteen years, during which the quality and quantity of this man’s food was carefully observed, body-weight, general good health, and physical vigor were all maintained, together with freedom from the ills of previous years and with a daily diet characterized by extreme simplicity. The chemical composition of the diet was likewise peculiar, particularly in its exceedingly low fuel value. The following table shows the amounts of proteid, fat, and carbohydrate consumed daily during the four periods designated:
| Period. | Proteid. | Fat. | Carbo- hydrate. | Calories. | Calories per Kilo- gram. | Proteid per Kilo- gram. |
|---|---|---|---|---|---|---|
| grams | grams | grams | grams | |||
| 1889–1892 | 79.8 | 21.7 | 152.0 | 1125 | 26 | 1.90 |
| 1892–1894 | 85.2 | 27.0 | 152.0 | 1200 | 28 | 2.03 |
| 1894–1900 | 87.0 | 30.1 | 150.1 | 1230 | 29 | 2.07 |
| 1900–1903 | 84.4 | 73.7 | 148.3 | 1600 | 38 | 2.00 |
Especially noticeable here is the low intake of fat and carbohydrate, with the corresponding low fuel value, and also the relatively high consumption of proteid, averaging 2.0 grams daily per kilogram of body-weight. Dr. Fenger concludes that for a man of this age and weight, with the relative inactivity characteristic of old age, a heat value in the intake of 30 calories per kilogram of body-weight is quite sufficient for the needs of the body. This may be quite true, but to maintain nitrogen equilibrium under such conditions requires a larger intake of proteid food than is desirable. It will be observed that in the last period of four years a very decided change in the diet was instituted; proteid was diminished somewhat, but the noticeable change was the decided increase in fat, produced in large measure by the substitution of whole milk, with its contained cream, for skim milk. In the words of Dr. Fenger, this change was necessitated by the appearance of gout in the subject. From superficial examination of the dietary of the preceding eleven years there would seem no occasion for criticising the subject for high living, and yet I believe we are quite within the limits of reason in saying that the proteid exchange for a subject of this body-weight was altogether too high. The heat requirements of the body were being met in an unnecessarily large degree from the breaking down of proteid material, with consequent formation of excessive nitrogenous waste, among which uric acid was plainly conspicuous.
One comment to be made here is that meat and other rich purin-containing foodstuffs are not the only source of gout and uric acid. Excessive proteid katabolism, both exogenous and endogenous, is a possible source of danger in this respect, and the above subject, though living on an exceptionally simple diet, was consuming far more proteid per kilogram of body-weight than was necessary or desirable. Increase of fatty food naturally served to diminish the rate of proteid katabolism, and this could have been advantageously accompanied by a still greater reduction in the amount of proteid ingested, and a larger addition of non-nitrogenous foodstuffs. In old age, there is naturally a slowing down of the metabolic processes, and both nitrogen equilibrium and body equilibrium can be satisfactorily maintained by a relatively small intake of food and with gain to the body; but there is every reason to believe that economy in proteid food can be more advantageously adopted than economy in non-nitrogenous foodstuffs.
Finally, we may call attention to the many possibilities of an intelligent modification of the daily diet to the temporary needs of the individual. The season of the year, summer and winter, the climate, the degree of activity of the body, the state of health, temporary ailments, etc., all present special conditions which admit of particular dietetic treatment. In hot summer weather, for example, there is plainly less need for food than in the cold winter season, especially for fat with its high calorific value. During the cold part of the year, the lower temperature of the surrounding air, with the tendency toward greater muscular activity, calls for more extensive chemical decomposition in order to meet the demand for heat, and the energy of muscular contraction. There is perhaps no special reason for any material change in the amount of proteid food consumed in the two seasons, except in so far as it may seem desirable at times to take advantage of the well-known stimulating properties of proteid to whip up the general metabolism of the body, in harmony with the principle that all metabolic processes may need spurring to meet the demands of a greatly lowered temperature in the surrounding air.
Fuel value, however, should be increased somewhat during the winter months in our climate. Fat promises the largest amount of energy, but there is more of a tendency to store up excess of fat than of carbohydrate, hence the latter foods have certain advantages as a source of the additional energy needed during cold weather. In warm weather, it should be our aim to diminish unnecessary heat production as much as possible, though it must be remembered that the body is to be maintained approximately at least in equilibrium, and this calls for an adequate amount of food. Lighter foods, however, may be advantageously employed, such as fruits, vegetables, fresh fish, etc. Fats and fat meats especially are to be avoided, not only because there is no specific need for them, but particularly on account of a greater sensitiveness of the gastro-intestinal tract during the hot seasons of the year, that is liable to result in a disturbance whenever undue quantity of rich or heavy food is taken. Further, in hot summer weather we may advantageously live more largely on foods served cold, and thereby avoid the heat ordinarily introduced into the body by hot fluids and solids. These, however, are all obvious physiological truths, constituting a form of physiological good sense the application of which calls for no special expert knowledge.
Less obvious, though no less important, is the partial protection that can be afforded to weakened or disabled kidneys by judgment and discrimination in the matter of diet. In acute or chronic nephritis, forms of so-called Bright’s disease, is there not danger of overtaxing organs already weakened by placing upon them the daily duty of excreting large amounts of solid nitrogenous waste, as well as of the various inorganic salts which are so intimately associated with many of the organic foodstuffs? The consumption of excessive and unnecessary amounts of proteid food simply means the ultimate formation of just so much more urea, uric acid, etc., which must be passed out through the kidneys. In the words of Bunge, “There is no organ in our body so mercilessly ill treated as the kidneys. The stomach reacts against overloading. The kidneys are obliged to let everything pass through them, and the harm done to them is not felt till it is too late to avoid the evil consequences.” It would seem the part of wisdom, therefore, to adjust the daily intake of proteid food to as low a level as is consistent with the true needs of the body, in those cases where the kidneys are at all enfeebled, or where it seems desirable to exercise due precaution as a possible means of prevention.
Equal care is frequently called for in connection with the mineral matters which enter so largely into many natural foodstuffs, or which are introduced as condiments. As an illustration, we may note one or two peculiarities in the distribution of sodium and potassium salts in the tissues of the body. Potassium is an indispensable constituent of every living cell, and the latter has the power of absorbing and holding on to such amounts of this particular element as may be necessary for the functional activity of the tissue of which it is a part. Sodium, on the other hand, stands in a different relationship to living structures. It is widely distributed, but in the higher animals, as in man, sodium salts are most abundant in the fluids of the body, notably in the plasma of the blood. Herbivorous animals have a strong liking for sodium chloride or common salt, but this is not true of carnivorous animals; indeed, the latter animals have a great dislike for salty articles of food. Vegetable products are all rich in potassium salts, whereas ordinary animal foods, such as meat, eggs, milk, and blood, are relatively poor in this element.
It is claimed that the abundance of potassium salts in vegetable foods is the cause of the apparent need for sodium chloride by herbivorous animals, and in lesser degree by man. This is explained by supposing that when the salts of potassium reach the blood by absorption of the vegetable foods, an interchange takes place with the sodium chloride of the blood plasma. “Chloride of potassium and the sodium salt of the acid which was combined with the potassium are formed. Instead of the chloride of sodium, therefore, the blood now contains another sodium salt, which did not form part of the normal composition of the blood, or at any rate not in so large a proportion. A foreign constituent or an excess of a normal constituent, i. e., sodium carbonate, has arisen in the blood. But the kidneys possess the function of maintaining the same composition of the blood, and of thus eliminating every abnormal constituent and any excess of a normal constituent. The sodium salt formed is therefore ejected by the kidneys, together with the chloride of potassium, and the blood becomes poorer in chlorine and sodium. Common salt is therefore withdrawn from the organism by the ingestion of potassium salts. This loss can only be made up from without, and this explains the fact that animals which live on a diet rich in potassium, have a longing for salt” (Bunge). It is certainly a fact worthy of note that man takes only one salt as such in addition to those that are naturally present in his food, and it is equally significant that sodium chloride is by no means lacking in ordinary foodstuffs. If the individual lives entirely on animal foods, he has no desire for salt, but as soon as he adopts a vegetable diet the craving for salt shows itself. Vegetable foods, however, are not all alike in their content of potassium salts; some, like rice, contain relatively little, while others, like potatoes, peas, and beans, are comparatively rich in this element.
We may recognize in these statements a physiological demand for a certain amount of salt, especially when vegetable foods enter into the daily dietary, but there is no justification for the employment of such quantities as are generally made use of. Where the vegetable food is largely rice, a small fraction of a gram of salt is really sufficient for all physiological purposes; and in those cases where ordinary cereals, legumes, potatoes, etc., constitute the chief part of the dietary, a few grams of salt, at the most, will suffice to meet the daily needs. Common usage, however, frequently raises the amount consumed to 25 grams or more per day, the bulk of which is at once eliminated through the kidneys; thereby entailing a certain amount of renal activity, which must, it would seem, constitute something of a strain upon organs ordinarily hard worked at the best. “Do we not impose too great a task upon them, and may it not be fraught with serious consequences? When on a diet of meat and bread, without salt, we excrete not more than from 6 to 8 grams of alkaline salts in twenty-four hours. With a diet of potatoes, and a corresponding addition of salt, over 100 grams of alkaline salts pass through the kidneys in the day. May not there be danger in this? The habit of drinking spirituous liquors, which moreover is reckoned one of the causes of chronic nephritis, also brings about the immoderate use of salt, and thus one sin against nature leads to another” (Bunge).
The moral we would draw (from these observations) is that in weakened conditions of the kidneys there is reason in reducing the rate of proteid exchange to the lowest level consistent with the maintenance of equilibrium and the preservation of strength and vigor, thereby diminishing the amount of nitrogenous waste to be eliminated and the consequent strain upon these organs. Further, there is suggested moderation in the amount of salt to be used daily, and some circumspection in the amount and quality of vegetable foods consumed in order to regulate more effectually the quantity of saline waste to be handled by the kidneys. These conclusions are just as worthy of consideration as the more obvious rule that in diabetes or glycosuria proper precaution must be observed in the eating of carbohydrate foods. In gout and rheumatism, accumulated physiological knowledge teaches plainly the necessity of avoiding those foods that are rich in purin-containing compounds. Uric acid owes its origin in part at least to substances of this class; and as an ounce of prevention is worth more than a pound of cure, we may by proper moderation in the use of such foods save ourselves from the disagreeable effects of accumulated uric acid deposits.
In conclusion, the nutrition of man, if it is to be carried out by the individual in a manner adapted to obtaining the best results, involves an intelligent appreciation of the needs of the body under different conditions of life, and a willingness to accept and put in practice the principles that scientific research has brought to light, even though such principles stand opposed to old-time traditions and customs. The master words which promise help in the carrying out of an intelligent plan of living are moderation and simplicity; moderation in the amount of food consumed daily, simplicity in the character of the dietary, in harmony with the old saying that man eats to live and not lives to eat. In so doing there is promise of health, strength, and longevity, with increased efficiency, as the reward of obedience to Nature’s laws.