No good purpose would be served by entering into more detail on the question of nutrients, and doubtless the average man will be better satisfied to know how to apply in a practical manner the information he has already acquired. Fortunately perhaps for himself, Nature has already taken this matter out of his hands by decreeing that experience guided by a healthy appetite is the most convenient method for selecting the most appropriate articles of diet. Each nation has solved this problem for itself in very much the same way, and the results are of the most interesting character.

Volumes have been written upon this subject, and its study is most entrancing, as it is only natural to associate the success or failure of a nation with the food which supplies or fails to supply its energy and vitality. It is difficult, however, to draw any practical conclusions in connection with this question without special reference to climate and occupation, and it is found that a low temperature and hard physical labour necessitate a greatly increased quantity of food. With an indoors occupation where the temperature is hardly less than the average out-of-doors summer temperature, the requirement of food will not vary much. Where, however, the indoor worker perspires very freely, then more food will be necessary to compensate for the large amount of heat carried off by evaporation of the perspiration.

Size and weight are of course important in determining the quantity of food, and for this reason the average woman eats about 20 per cent, less than the average man, whilst a child from five to ten years eats about half the quantity of the average man.

From the theoretical point of view, excessive labour should create a greater demand for the so-called energy-producing foods, fats, and carbohydrates, but experience teaches that proteins are called for in proportionate quantities. During the first week of a holiday and after a protracted illness there is a greater demand for proteins in the form of animal food, but this is soon gratified as indicated by the appetite returning to the normal. The greater indeed the amount of muscular exertion, the greater is the quantity of food required.

Mental work, on the other hand, does not seriously encroach upon the reserves, as is evidenced by the fact that it appears to have very little effect in increasing the excretion of waste matters. Although it is well to recognise that there is no special brain food per se, nevertheless brain workers require an easily digested ration with a slightly augmented proportion of protein.

The scientific method of measuring the amount of food required is not of much value to the man at the dining-table. It is sufficient to state that the average business man pursuing a more or less sedentary occupation requires daily about 3 ounces of protein, 2 ounces of fat, and 12 ounces of carbohydrates. These quantities are of course water-free, and do not take into account the fluid originally contained in the food stuff or added during the process of cooking. Roughly speaking, this is about 75 per cent. more, so that such an individual would eat in the course of a day a little over 4 lbs. of food in the condition in which it is served at the dining-table. Doubtless this is an eye-opener for many people, especially those who are in the habit of thinking and saying that they hardly eat anything at all, but it is quite a usual matter for a lusty young fellow to eat daily from 7 to 8 lbs. of food as served in the ordinary course at meal-times.

Specimen Menu For A Day

The following is a specimen of the food actually consumed in a day by a fairly active professional man, weighing 10 stone 7 lbs., and no doubt will be more acceptable than many pages of instructions:

Breakfast, 8.15 a.m.

This makes a total of 58 1/2 ounces, or nearly 4 lbs. of food. Probably most business men consume a great deal more than this without obtaining much additional energy for their daily work, and a careful scrutiny of the amounts will reveal items which look ridiculously attenuated.

But although the body is able to accommodate itself to one or more occasional heavy meals, it is never wise regularly to eat even a little more than is essential to supply its requirements. The secret of successful nutrition is to vary the quantity and character of the food according to the amount of work. After hard muscular exertion a proportionately greater quantity of cereal such as rice, sago, or tapioca pudding, or even beans, peas, and lentils, may be consumed, whereas during a long series of sedentary working days, sweets, pastries, and most starchy foods must be reduced to a minimum, and easily digested protein foods such as chicken and white fish be selected.

During cold weather, pork, duck, eel, salmon, mullet, and other fatty fish, with an extra supply of bacon and butter, will best provide the caloric necessities, whilst during the heat of summer fatty foods of all kinds should be reduced to a minimum, and fruits and vegetables substituted.

Some kind of raw food should be eaten every day, if not at every meal, and for this purpose fruits in the ordinary form, or with vegetables in salads, will be found most convenient. To encourage mastication, some dry food such as Force, Triscuit, Grape Nuts, biscuit, or zwieback should be eaten at each meal. Not more than half a pint of fluid should be drunk, preferably in sips at the close of each meal, with two cups of weak China tea unaccompanied by food in the afternoon, and half a pint of hot water first thing in the morning and last thing at night.

Where it is necessary to economise time in the middle of the day, lunch may be made to consist of a milk pudding with some stewed fruit, and then a typical English dinner of soup, fish, joint, sweets, bread, cheese, and dessert may be indulged in not later than 7 p.m. It will be noted that the detailed menu provides for midday dinner with one item of animal food, whilst supper contains the other. This is intended for those who have leisure to spare for the digestion of such a meal, but those who are not compelled to use their muscles much would be well advised to exclude the animal food in the evening, or at least substitute an egg.

Many persons over middle age will find that they are incapable of eating even as much as is mentioned in the specimen dietary, whereas younger men, especially those who indulge freely in exercise, may be able safely to eat quite twice as much. If consistent over-eating be eschewed at all times, and all sources of toxaemia be eliminated, then such misadventures as a gouty old age, rheumatism, and so-called "chill" on the liver need never be experienced.