CHAPTER I.
TIMES OF EATING.
The selection of food only one element in sound digestion—Other conditions essential—Times of eating—No stated hours for eating—Five or six hours of interval between meals generally sufficient—But must vary according to circumstances—Habit has much influence—Proper time for breakfast depends on constitution, health, and mode of life—Interval required between breakfast and dinner—best time for dinner—circumstances in which lunch is proper—late dinners considered—their propriety dependent on mode of life—Tea and coffee as a third meal—useful in certain circumstances.—Supper considered.—General rule as to meals.—Nature admits of variety,—illustrations—but requires the observance of principle in our rules.
Having in the first part of the present work traced the progress of the food through its successive stages of preparation for becoming a constituent element of the animal frame, and examined the structure and nature of the various organs engaged in digestion, I shall now endeavour to turn the exposition to account, by making it as far as possible subservient to a closer and more rational observance of the laws of digestion, and to a better adaptation of diet and regimen to different ages, sexes, and constitutions, than that which is generally prevalent. I am deeply sensible of the imperfections which will abound in this part of the work; but, at the same time, I am so strongly impressed with the urgent importance of the subject, and with the success which will infallibly attend its further investigation on sound physiological principles, that I consider the likelihood of personal failure to be of very secondary importance, when compared with the benefits which will accrue to society from the exertions of others whose labours may be more profitably directed by an acquaintance with the guiding principles unfolded in these pages.
According to the popular notion of dietetics, the selection of the proper kind of food seems to constitute the only condition required for the enjoyment of healthy digestion. Hence medical men are constantly questioned whether this or that article of diet is good or bad for the stomach, while curiosity rarely if ever extends so far as to inquire whether Nature has annexed any other conditions which also it may be expedient to know and to observe. In reality, however, the choice of aliment is but one out of many circumstances which require to be attended to; and it often happens that the same food which is digested with ease when the collateral conditions are fulfilled, will remain for hours on the stomach unaltered when they are neglected. Some of these conditions, therefore, I shall now endeavour to point out. And first, of
Times of Eating.—If we look to the exposition of the objects of eating already given in treating of appetite, it will be obvious that Nature intended us to regulate our meals by the demands of the system, and not to eat at stated hours as a matter of course, whether nourishment were required or not. If we are engaged in occupations which induce a rapid expenditure of material, or if growth is going on so fast as to require unusually ample supplies, food ought to be taken both more frequently and in larger quantity than when we are differently circumstanced; or, in other words, food ought to bear a relation to the mode of life and circumstances of the individual, and not be determined by a reference to time alone.
In reality, however, the animal economy is constituted with so strong a tendency to periodical activity, that as great an approximation as possible ought to be made to fixed times of eating. In general little difficulty and much advantage attend the arrangement; because where the mode of life is regular and nearly the same throughout a whole class, the same waste will go on, and consequently the demand for a supply of nourishment in all the individuals composing it will be felt at nearly the same intervals, subject only to such variations as are induced by original differences of age and constitution. As regards each class, therefore, regularity in the recurrence of their meals is not less natural than advantageous; and it is only when we attempt to combine a given order of diet with different and even incompatible modes of life that Nature refuses to sanction the arrangement.
So strong indeed is the tendency to periodicity in the system, that appetite returns for a time at the accustomed hour, even after the mode of life, and consequently the wants of the system, have undergone a change; and if not gratified it again subsides. Ultimately, however, it calls with too strong a voice to allow of its being thus disregarded.
Nature has accorded to man considerable latitude in fixing the interval within which the demands of appetite must be gratified, and in this provision has obviously had in view the infinite variety of circumstances in which he may be placed in the discharge of his numerous duties. As a general rule, five or six hours should elapse between one meal and another—longer if the mode of life be indolent, shorter if very active. Digestion occupies from three to five hours, according to the nature of the meal and circumstances of the case, and the stomach requires an interval of rest after the process is finished, to enable it to recover its tone, before it can again enter upon the vigorous performance of its function. Appetite, accordingly, does not begin to shew itself till some time after the stomach has been empty, and if food be taken before it has recovered its tone, the secretion of gastric juice and the contraction of its muscular fibres are alike imperfect, and digestion consequently becomes impaired. If, again, food be taken before the digestion of the preceding meal be completed, the result will be still worse; because the whole of the gastric juice which the stomach can secrete being already engaged in the solution of the first meal, the one subsequently taken necessarily remains unsupplied, and consequently liable to undergo the same chemical change—fermentation—which would occur in it if exposed out of the stomach to an equal degree of heat and moisture. And, therefore, Dr Kitchener, in alluding to the advantages arising from giving the stomach an occasional rest, truly and forcibly remarks, that “unless the constitution is so confoundedly debilitated that the circulation will not run alone, abstinence is the easiest—cheapest—and best cure for the disorders which arise from indigestion or intemperance.” (P. 160.) In these cases, indeed, abstinence is to the exhausted stomach what repose is to the wearied muscles, and hence the benefits resulting from it.
The interval between each meal ought to be longer or shorter in proportion to the quantity eaten, and to the more or less active habits of the individual; and it would be absurd to fix the same standard for all. A strong labouring man, whose system is subjected to great waste from being engaged all day in hard work, will require not only more frequent but more copious meals than an indolent and sedentary man; and those who eat very little will require to eat at shorter intervals than those whose meals are heavy. An invalid on restricted diet may thus require to eat every four hours, where formerly, with a more copious diet, once in six hours was sufficient. Some indeed are so constituted as to require only one or two abundant meals in twenty-four hours.