NUTRITION AND DIET
I
THE SCIENCE OF NUTRITION
The importance of some general knowledge of the principles of nutrition and the nutritive values of foods is not generally realised. Ignorance on such a matter is not usually looked upon as a disgrace, but, on the contrary, it would be commonly thought far more reprehensible to lack the ability to conjugate the verb 'to be' than to lack a knowledge of the chemical properties of the food we eat, and the suitability of it to our organism. Yet the latter bears direct and intimate relation to man's physical, mental, and moral well-being, while the former is but a 'sapless, heartless thistle for pedantic chaffinches,' as Jean Paul would say.
The human body is the most complicated machine conceivable, and as it is absurd to suppose that any tyro can take charge of so comparatively simple a piece of mechanism as a locomotive, how much more absurd is it to suppose the human body can be kept in fit condition, and worked satisfactorily, without at least some, if only slight, knowledge of the nature of its constitution, and an understanding of the means to satisfy its requirements? Only by study and observation comes the knowledge of how best to supply the required material which, by its oxidation in the body, repairs waste, gives warmth and produces energy.
Considering, then, that the majority of people are entirely ignorant both of the chemical constitution of the body, and the physiological relationship between the body and food, it is not surprising to observe that in respect to this question of caring for the body, making it grow and work and think, many come to grief, having breakdowns which are called by various big-sounding names. Indeed, to the student of dietetics, the surprise is that the body is so well able to withstand the abuse it receives.
It has already been explained in the previous essay how essential it is if we live in an artificial environment and depart from primitive habits, thereby losing natural instincts such as guide the wild animals, that we should study diet. No more need be said on this point. It may not be necessary that we should have some general knowledge of fundamental principles, and learn how to apply them with reasonable precision.
The chemical constitution of the human body is made up of a large variety of elements and compounds. From fifteen to twenty elements are found in it, chief among which are oxygen, hydrogen, carbon, nitrogen, calcium, phosphorus, sodium, and sulphur. The most important compounds are protein, hydrocarbons, carbohydrates, organic mineral matter, and water. The food which nourishes the body is composed of the same elements and compounds.