Nutrition may be conveniently divided into two phases--positive and negative--corresponding to periods of eating and periods of abstaining from food. Negative nutrition has received the terms fasting, inanition, starvation. Fasting and starving are separate phenomenai well demarked from each other. Inanition covers both these processes.

Fast is derived from the Anglo-Saxon word, faest, which means "firm" or "fixed." The practice of going without food at certain times was called fasting, from the Anglo-Saxon, faesten, to hold oneself from food. Like most English words, the word fasting has more than one meaning. Thus, the dictionary defines fasting as "abstinence from food, partial or total, or from proscribed kinds of foods." In most religious fasts abstinence from proscribed foods is all that is meant. We may define it thus: Fasting--is abstention, entirely or in part, and for longer or shorter periods of time, from food and drink or from food alone.

A misuse of the term, fasting, is quite common. I refer to the use of the word fasting when a particular diet is referred to. We read and hear of fruit fasts, water fasts, milk fasts, etc., when talking of a fruit diet, a milk diet, etc. A fruit fast is abstinence from fruit; a milk fast is abstinence from milk; a water fast is abstinence from water.

The dictionary defines a diet as a "regulated course of eating and drinking, a specially prescribed regime. The daily fare, victuals, allowance of food; rations." To "diet" is "to regulate or restrict the food and drink according to a regime; to eat carefully or sparingly. To take food; to eat."

Fasting, as we employ the term, is voluntary and entire abstinence from all food except water. "Little driblet meals," says Dr. Chas. E. Page, "are not fasting. There should not be a mouthful or sip of anything but water, a few swallows of which would be taken from time to time, according to desire." We do not employ the word fasting to describe a diet of fruit juice, for example.

Inanition is a technical term literally meaning emptiness, which is applied to all forms and stages of abstinence from food and to many forms of malnutrition due to various causes, even though the person is eating. Prof. Morgulis classifies three types of inanition according to origin, as follows:

1. "Physiological inanition which is a normal, regular occurrence in nature. The inanition constitutes either a definite phase in the life cycle of the animal, it is a seasonal event, or it accompanies the periodic recurrence of sexual activity." The cases of the salmon and seal and of hibernating animals are examples of this.

2. "Pathological inanition," which is in "various degrees of severity associated with different organic derangements"--obstruction of the alimentary canal (oesophageal stricture)," "inability to retain food (vomiting)," "excessive destruction of body tissues (infectious fevers)," and "refusal to take food either because of loss of appetite or mental disease."

3. "Accidental or Experimental Inanition." "In this category, of course, belong all individual experiences which have been the subject of carefully conducted scientific investigation."

To this should be added a fourth classification, a class with which Prof. Morgulis seems to be very largely unacquainted, which is largely or wholly voluntary but in which abstinence from food is not for mere experimental purposes, but for the promotion or restoration of health. I prefer to call this hygienic fasting. Others refer to it as therapeutic fasting. Fasting of this type is not wholly voluntary in acute "disease," except in the sense that all instinctive action is voluntary. It is the hygienic fast that we are chiefly concerned with in this volume, although we are going to make use of data gained from the other types of fasting that may be of service to us in better understanding and more intelligently conducting a fast.

In his Inanition and Malnutrition, Jackson says the term starvation "is more frequently used to indicate the extreme stages of inanition, leading to death." Unfortunately, this is too often not the case. Too often the term starvation is applied to the whole period of abstinence from food from the first day to the end in death.

Carrington says: "Many doctors speak of 'the fasting or starvation cure'--which simply shows that they don't know what they are talking about. Fasting is an absolutely different thing from starvation. One is beneficial; the other harmful. One is a valuable therapeutic measure; the other a death-dealing experiment."--Physical Culture, May, 1915.

A distinction must be made between fasting and starving, as will be seen as our study proceeds. Fasting is not starving. The difference between fasting and starving is immense and well demarcated. Dr. Hazzard expressed this fact in these words: "Starvation results from food denied, either by accident or design to a system clamoring for sustenance. Fasting consists in intentional abstinence from food by a system suffering from disease and non-desirous of sustenance until rested, cleansed, and ready for the labor of digestion."

Fasting is neither a "hunger cure" nor a "starvation cure," as it is sometimes called. Fasting is not starving. The fasting person is not hungry, and fasting is not a method of treating or curing "disease." Dr. Page says, "The term frequently applied--'starvation cure'--is both misleading and disheartening to the patient: the fact is he is both starved and poisoned by eating when the hope of digestion and assimilation is prohibited, as is, in great measure, the case in all acute attacks and more especially when there is nausea or lack of appetite."

Fasting is a rest--a physiological vacation. It is not an ordeal nor a penance. It is a house-cleaning measure which deserves to be better known and more widely used.