Knowledge concerning diet and digestion, both valuable and useless, can be had without asking.
The grocer sends you with your purchases a pamphlet on nourishment; a restaurant menu furnishes a few thoughts on mastication; warnings against coffee drinking glare at you in the street cars; library shelves are crowded with books on health, food, and so on. When we go out to luncheon or have guests to dinner, matters of diet and digestion are talked of so freely that we seem to eat with a chart of the digestive tract before our mind's eye, and we suspiciously watch while innocent food, which unobserved might have given vitality and cheer, becomes a cause of weariness and depression.
To know enough to feed a family wisely, agreeably and economically without becoming over-careful, or perhaps a faddist in regard to food is indeed very difficult. For one thing, avoid fixed rules and arbitrary ideas in catering. Digestions are as different as noses and thumb signatures; one can, therefore, neither invariably forbid one thing nor insist upon another. On the contrary, digestions are as alike in general as noses and thumb signatures, and it is, therefore, unnecessary and harmful that any member of a family should be especially provided for and cooked for unless that person is an invalid living upon a prescribed diet.
I believe a simple and successful rule for those who have nothing to do with the meals except to eat them is: Eat what is set before you and find something amusing to say or to think about. It is a little difficult at first, both to eat things one does not especially care for, and to think up something amusing, but it soon becomes a habit. Meals are not times for stoking an engine, even with the most thoughtfully selected fuel, but times for the renewal of life. There is a meditative by-path which leads off from this thought concerning the reasons that meals are in some cases the most sacred and spiritual rites of religion. We must not wander there, however, but may note in passing the reason for saying Grace at meals which is suggested by this thought. A Grace blesses a gift of new life and is a thanksgiving for it.
But that meals shall fulfil their office of renewing life and gladness, it is necessary that the woman who selects and arranges them shall have some knowledge and shall expend some care. It need not be elaborate knowledge, nor burdensome care, just a usual quantity of each.
It has been discovered that human bodies are composed of chemical elements just as are cabbages and doctors' prescriptions. Some of the elements of which we are composed are oxygen, hydrogen, carbon, nitrogen, phosphorus, sulphur, iron, potassium, calcium, and there are others yet. It would seem a simple matter to find out just how much of each of these things we contained and then to keep up the supply by eating or inhaling them in the required quantities, but you can be sure there is nothing as dull and matter-of-fact as that in this interesting creation. We are not doctors' prescriptions, we are even a bit more remarkable than cabbages, and it is not just correctly measured proportions of oxygen, nitrogen and potassium that we need, but energy, and heat, and flesh, and blood. Therefore, it is that when we consult some wise table of statistics in which the nourishing value of food is given, we do not find it given in terms of oxygen and hydrogen and the rest, but in terms which indicate heat, energy and building material.
Tables of the composition of foods are usually made in the following terms: Refuse, Water, Protein, Fat, Carbohydrates, Ash. Added to these there will often be a division headed "Calories." The calorie nevertheless is not a food substance, it is the unit by which energy-giving heat is measured. Just as a ribbon is measured in yards and molasses in cupfuls, so heat is measured in calories.
"Refuse" means that part of food which cannot be eaten or which could not be used by the body if it were eaten, as bones, fibres, seeds, parings, pods and shells.
"Protein" is an inclusive word for the chief substances in food which the body can use in rebuilding itself as use wears it out.