If fruit, succulent vegetables, or cooked food, containing much water be freely used, and there be little perspiration, it is possible to do without drinking; but there is danger of taking insufficient water to hold freely in solution the waste products excreted by the body.
Aerated drinks, except a very few of the best, and non-alcoholic beers and wines, are generally unwholesome, from their containing preservatives, foaming powders, artificial flavourings, &c.
Stimulants.—Tea and coffee contain an alkaloid theine, besides volatile oils, tannin, &c. Cocoa contains the milder alkaloid, theobromine. They stimulate the heart and nervous systems; tea and coffee have also a diuretic effect. Formerly they were erroneously thought to lessen tissue waste. These alkaloids, being purins, are open to the general objections named elsewhere. Stimulants do not impart energy or force of any kind, but only call forth reserve strength by exciting the heart, nervous system, &c., to increased activity. This is followed by a depression which is as great, generally greater, than the previous stimulation. Except, perhaps, as an occasional medicine, stimulants, should be avoided. Analysis of cocoa shows a good proportion of proteids and a very large quantity of fat. The claim that it is a valuable and nutritious food would only be true if it could be eaten in such quantities as are other foods (bread, fruits, &c.). Were this attempted, poisoning would result from the large quantity of alkaloid. The food value of half a spoonful or thereabouts of cocoa is insignificant. Certain much advertised cocoa mixtures are ridiculous in their pretentions, unscientific in preparation, and often injurious.
Cereals.—The most valuable is wheat, from its proteid being chiefly in the form known as gluten. From its tenacity, gluten enables a much better loaf to be produced from wheat than from any other cereal. The outer part of the grain is the richest in mineral matter and proteid. Wheatmeal bread shows a considerably higher proteid value than white. A large proportion of the proteid in the outer coats of the wheat berry is, however, not digested, and in some experiments the waste has been enough to quite nullify its seeming advantage over white bread. Coarsely ground, sharp branny particles in bread irritate the intestines, and cause excessive waste of nutriment; but finely ground wheatmeal is free from this objection, and is beneficial in preventing constipation. The comparative value of white and brown bread has been much discussed; it depends both on the quality of the bread and the condition of the digestive organs. Experiments on the digestion of bread and other things, have often been made on persons unaccustomed to such foods, or the foods have been given in excessive quantity. To those accustomed to it good wheatmeal bread is much pleasanter, more satisfying, and better flavoured than white; indeed, the latter is described as insipid. Most bakers' bread is of unsatisfactory quality. Flour and bread contain very little fat, the absence of which is considered a defect. This is remedied by the addition of butter, fat or oil, or by nuts, &c., which are rich in oil. These may be mixed with the flour prior to cooking, or used afterwards.
Oats contain a substance called avenin, apparently an alkaloid, which has an irritating action; the quantity is variable. It is to this that the so-called heating effect of oatmeal on some persons is due.
Prepared Cereals or Breakfast Foods.—Analyses were made of 34 of these cereal preparations by Weems and Ellis (Iowa State College Agricultural Bulletin, 1904). They report that the foods possess no nutritive value in excess of ordinary food materials; that the claim made for many pre-digested foods are valueless, and no reliance can be placed on the statement that they are remedies for any disease.
Oatmeal and other cereals are sold in packets as being partially cooked. We do not doubt that they have been subjected to a dry heat, but this has scarcely any effect on their starch and other constituents. The difference is a mechanical one. In rolled oats the grains are so cracked and broken, that on boiling with water, the water readily penetrates and more quickly cooks them throughout. There are other prepared cereal foods, but we doubt whether they are thoroughly cooked after the short boiling directed on the labels. They are a great convenience where it is difficult to get the time necessary for cooking the ordinary cereals. Coarsely ground wheat is too irritating when made into porridge, but there are some granulated wheats sold in packets, which are quite suitable. The Ralston breakfast food is excellent. They are rich in the phosphates and salts, found in the outer part of the grain. One cereal preparation called Grape Nuts, has had its starch converted into maltose and dextrin (maltose being a sugar), by a scientific application of the diastase of the grain. It is consequently easier of digestion and requires no cooking. It is beneficial for some forms of indigestion. There are several competing foods of less merit, the starch being less perfectly changed; one at least of which is objectionably salt. Properly cooked starch is readily digested by healthy persons, and for them malted food is of no special value.
Pulse, or Legumes, includes haricots and other beans, peas and lentils. The proteid contained is that variety known as legumin, which is either the same, or is closely allied, to the casein of milk and cheese. Pulse is very rich in proteid, the dried kinds in general use, contain 24 or 25 per cent. The richest is the soy-bean, which is used in China and Japan, it contains 35 per cent., besides 19 per cent. of fat. Pulse requires thorough cooking, haricots taking the longest time. Split lentils are cooked sooner, and are better digested; this is chiefly due to the removal of the skins. The haricots, bought from small grocers who have a slow sale, are often old, and will not cook tender. Pulse is best adapted to the labouring classes; the sedentary should eat it sparingly, it is liable to cause flatulence or accumulation of gas in the intestines, and constipation. Haricots are easier to digest when mashed and mixed with other food. Pulse was formerly stated to leave much undigested residue. Recent experiments have shown that it is satisfactorily digested under favourable conditions. Strümpell found beans in their skins to leave a large proportion of proteid matter unabsorbed. Lentil meal mixed with other food was digested in a perfectly satisfactory manner. Another experimenter (Rubner) found that when even the very large quantity of 1-1/8 pound of dried split peas per day were eaten, only 17 per cent. of proteid matter was unabsorbed, which compares very well with the 11 per cent. of proteid left from a macaroni diet, with which the same man was fed at another time. Had a reasonable quantity of peas been eaten per day, the quantity undigested would probably have differed little from that of other foods.
Nuts are, as a rule, very rich in oil and contain a fair proportion of proteid; when well masticated they are a very valuable food. Walnuts are one of the best, and the kernels can be purchased shelled, thus avoiding much trouble. They can be finely ground in a nut-mill and used for several purposes, mixed in the proportion of about two ounces to the pound of wheatmeal they produce a rich flavoured bread. They can also he used in sweet cakes and in rich puddings to increase their food value, lightness and taste. Pine kernels being very oily, can be used with flour in the place of lard or butter.
Fruits are generally looked upon as luxuries, rather than as food capable of supplying a meal or a substantial part of one. They are usually eaten only when the appetite has been appeased by what is considered more substantial fare. Fresh fruits contain a larger proportion of water than nearly all other raw foods, and consequently the proportion of nourishment is small; but we must not despise them on this account. Milk contains as much or more water. Certain foods which in the raw state contain very little water, such as the pulses and cereals when cooked absorb a very large quantity; this is particularly the case in making porridge. Cabbage, cauliflower, Spanish onions and turnips, after cooking contain even 97 per cent. of water. Roast beef contains on an average 48 per cent., and cooked round steak with fat removed 63 per cent. of water. It is customary at meal times to drink water, tea, coffee, beer, wine, &c. When a meal contains any considerable quantity of fresh fruits there need be no desire to drink. Notwithstanding that fruits contain so much water, a dietary consisting of fruits with nuts, to which may be added bread and vegetables, will contain less water than the total quantity usually consumed by a person taking the more customary highly cooked and seasoned foods. An advantage is that the water in fruits is in a wholesome condition, free from the pollution often met with in the water used for drinking purposes. Raw fruits favour mastication, with its consequent advantages, whilst cooked and soft food discourages it. Plums and what are termed stone fruits, if eaten in more than very small quantities, are apt to disagree. Persons with good digestions can take fruit with bread, biscuits and with uncooked foods without any inconvenience. Fruit is more likely to disagree when taken in conjunction with elaborately cooked foods. Many cannot take fruit, especially if it be acid, at the same time as cereal or starchy substances, and the difficulty is said to be greater at the morning's meal. If the indigestion produced is due to the acid of the fruit preventing the saliva acting on the starch, scientific principles would direct that the fruit be eaten quite towards the end of the meal. The same consideration condemns the use of mint sauce, cucumber and vinegar, or pickles, with potatoes and bread, or even mint sauce with green peas. Bananas are an exception, as not interfering with the digestion of starch. Bananas are generally eaten in an unripe condition, white and somewhat mealy; they should be kept until the starch has been converted into sugar, when they are both more pleasant and wholesome. Nuts and fruit go well together. For a portable meal, stoned raisins or other dried fruit and walnut kernels or other nuts are excellent.