CHAPTER XXI
DIET STANDARDS
(Discusses various foods and their food values, the quantities we need, and their money cost.)
I think there is no more important single question about health than the question of how much food we should eat. It is one about which there is a great deal of controversy, even among the best authorities. We shall try here for a common-sense solution. At the outset we have to remind ourselves of the distinction we tried to draw between nature and man. To what extent can civilized man rely upon his instincts to keep him in perfect health?
Let us begin by considering the animals. How is their diet problem solved? Horses and cattle in a wild state are adjusted to certain foods which they find in nature, and so long as they can find it, they have no diet problem. Man comes, and takes these animals and domesticates them; he observes their habits, and gives to them a diet closely approaching the natural one, and they get along fairly well. But suppose the man, with his superior skill in agriculture, taking wild grain and planting it, reaping and threshing it by machinery, puts before his horse an unlimited quantity of a concentrated food such as oats, which the horse can never get in a natural state—will that horse's instincts guide it? Not at all. Any horse will kill itself by overeating on grain.
I have read somewhere a clever saying, that a farm is a good place for an author to live, provided he can be persuaded not to farm it. But once upon a time I had not heard that wise remark, and I owned and tried to run a farm. I had two beautiful cows of which I was very proud, and one morning I woke up and discovered that the cows had got into the pear orchard and had been feeding on pears all night. In a few hours they both lay with bloated stomachs, dying. A farmer told me afterwards that I might have saved their lives, if I had stuck a knife into their stomachs to let out the gas. I do not know whether this is true or not. But my two dead cows afford a perfect illustration of the reason why civilized man cannot rely upon his instincts and his appetites to tell him when he has had enough to eat. He can only do this, provided he rigidly restricts himself to the foods which he ate in the days when his teeth and stomach and bowels were being shaped by the process of natural selection. If he is going to eat any other than such strictly natural foods, he will need to apply his reason to his diet schedule.
In a state of nature man has to hunt his food, and the amount that he finds is generally limited, and requires a lot of exercise to get. Explorers in Africa give us a picture of man's life in the savage state, guided by his instincts and very little interfered with by reason. The savages will starve for long periods, then they will succeed in killing a hippopotamus or a buffalo, and they will gorge themselves, and nearly all of them will be ill, and several of them will die. So you see, even in a state of nature, and with natural foods, restraint is needed, and reason and moral sense have a part to play.
What do reason and moral sense have to tell us about diet? Our bodily processes go on continuously, and we need at regular intervals a certain quantity of a number of different foods. The most elementary experiment will convince us that we can get along, maintain our body weight and our working efficiency upon a much smaller quantity of food than we naturally crave. Civilized custom puts before us a great variety of delicate and appetizing foods, upon which we are disposed to overeat; and we are slow observers indeed if we do not note the connection between this overeating and ill health. So we are forced to the conclusion that if we wish to stay well, we need to establish a censorship over our habits; we need a different diet regimen from the haphazard one which has been established for us by a combination of our instincts with the perversions of civilization.
Up to a few years ago, it was commonly taken for granted by authorities on diet that what the average man actually eats must be the normal thing for him to eat. Governments which were employing men in armies, and at road building, and had to feed them and keep them in health, made large scale observations as to what the men ate, and thus were established the old fashioned "diet standards." They are expressed in calories, which is a heat unit representing the quantity of fuel required to heat a certain small quantity of water a certain number of degrees. In order that you may know what I am talking about, I will give a rough idea of the quantity of the more common foods which it takes to make 100 calories: one medium sized slice of bread, a piece of lean cooked steak the size of two fingers, one large apple, three medium tablespoonfuls of cooked rice or potatoes, one large banana, a tablespoonful of raisins, five dates, one large fig, a teaspoonful of sugar, a ball of butter the size of your thumbnail, a very large head of lettuce, three medium sized tomatoes, two-thirds of a glass of milk, a tablespoonful of oil. You observe, if you compare these various items, how little guidance concerning food is given by its bulk. You may eat a whole head of lettuce, weighing nearly a pound, and get no more food value than from a half ounce of olive oil which you pour over it. You may eat enough lean beefsteak to cover your plate, and you will not have eaten so much as a generous helping of butter. A big bowl of strawberries will not count half so much as the cream and sugar you put over them. So you may realize that when you eat olive oil, butter, cream, and sugar, you are in the same danger as the horse eating oats, or as my two cows in the pear orchard; and if some day a surgeon has to come and stick a knife into you, it may be for the same reason.
The old-fashioned diet standards are as follows: Swedish laborers at hard work, over 4,700 calories; Russian workmen at moderate work, German soldiers in active service, Italian laborers at moderate work, between 3,500 and 3,700 calories; English weavers, nearly 3,500 calories; Austrian farm laborers, over 5,000 calories. Some twenty years ago the United States government made observations of over 15,000 persons, and established the following, known as the "Atwater standards": men at very hard muscular work, 5,500 calories; men at moderately active muscular work, 3,400 calories; men at light to moderate muscular work, 3,050 calories; men at sedentary, or women at moderately active work, 2,700 calories.
In the last ten or fifteen years there has arisen a new school of dietetic experts, headed by Professors Chittenden and Fisher of Yale University. Professor Chittenden has published an elaborate book, "The Nutrition of Man," in which he tells of long-continued experiment upon a squad of soldiers and a group of athletes at Yale University, also upon average students and professors. He has proved conclusively that all these various groups have been able to maintain full body weight and full working efficiency upon less than half the quantity of protein food hitherto specified, and upon anywhere from one-half to two-thirds the calory value set forth in the former standards.