Now we come to the true principle, namely Vital Economy. That which maintains health, and restores it when lost, is life. The fivefold food-medicine furnishes only the needed repair material. But the power that accomplishes these ends is life and life alone. This is evident from the fact that, without the vital response to the measures of health or cure, there is no cure. Those that ignore the life-power in their care of the sick do no good for them; on the other hand they do no harm. Life it is that does all the work, promoted and guided by Mother Nature, the hand-maid of God. When health is below par, it is life that restores it to its normal by efforts to eliminate foreign matter and to reduce the encumbrances that obstruct its functioning aright. A high level of health and ease in the cure of disease are both possible only when life-power is abundant, more than needful.

Also the one that has an abundance of vital power enjoys a high degree of the Natural Happiness mentioned before, and is therefore always contented and cheerful and free from the grossly weakening slavery to desires for mere pleasures. On the other hand the man with low vitality is miserable, whether he is engaged in work or not, as remarked by the epic poet, Milton, who composed the Paradise Lost.

Like water stored in a lake or reservoir and spent economically through sluices, vital power that is stored up in the body serves in all possible ways to safeguard health.

Also like money deposited in a bank and added to from time to time, vital power is available for all the urgent needs that may arise from time to time.

On the other hand, like the improvident one who mortgages his house and lands, the one that squanders his vitality by self-indulgence, actually mortgages his body to disease and death.

Life pervades and penetrates the whole of the living body that is unencumbered by foreign matter. (Even if some of this matter be not filth in a strict sense, it is a handicap to health, because matter in the wrong place is filth.) But in the encumbered body life-power is obstructed and hindered in its work by the foreign matter. Hence the necessity of keeping down the encumbrances and of making the body free from them by suitable hygienic means.

If the vital power be insufficient, due to improper and excessive expenditure, it can be made to suffice by sensible economy in the expenditure, reducing the waste of vitality through channels that can be profitably closed. For this purpose measures like continence (Brahmacharya), fasting or abstemious eating, are useful and necessary. By these measures the foreign matter is eliminated and the body lightened, and then more vital power flows into the body from its mysterious source, whatever it may be.

When there is abundant vitality, the body feels light, the tissues are clean, and the bodily figure is normal and comely. Quite otherwise are the effects if life-power is reduced to a low level. For life-power is lessened by filthy foreign matter and by drug-poisons. Herein we must remember the categorical statement of Dr Alonzo Clark that "every dose (of medicine) diminishes the patient’s vitality".

The greatest waste of power occurs in the work of food-disposal. By this waste life is greatly weakened, encumbrances increase and diseases occur again and again, become worse and worse.

It is true that weakness of life occurs after sexual indulgence also. But men become victims of lust, chiefly because they overeat, thereby poisoning their brains and thus producing discontent and cravings. Hence the practice of Dietetic Righteousness is fundamental to health of mind and body. And of Dietetic Righteousness, Vital Economy is the chief part.

The practice of moderation and self-control in the sex-life is usually understood to be the meaning of the term Brahmacharya, but we may consider self-control in all kinds of indulgence as included in the meaning of that word. It is the non-observance of Brahmacharya in this wide sense that tends to loss of health. And if the same course of wrong conduct be persisted in, where is the chance of the person recovering good health? But if he submits himself to the discipline that will be detailed here, and thus increase his store of vitality—his Vital Reserve—then to him Nature will vouchsafe good health.

By excessive attachment to enjoyments one comes to disregard the rules of hygienic living; and this leads to loss of vitality. By communion with the four higher sources of health—namely Ether, Air, Light, and Water—Vital Power is maintained. But it is by the encumbering toxic filth that communion is hindered. Of all these four, the Ether-power is the subtlest and most important. And more of this power is received by observing Brahmacharya in the wider sense given above. Perhaps Life is the same as this subtlest of all the five elements of creation. Hence access to this source of life must be kept up for the maintenance of a high level of vitality.

In the sexual life the married man must economise his vitality. That is his Brahmacharya, not absolute abstinence. It is said that the waste of semen is weakening. But it is the waste of vital power that is the real weakening of life. It is through loss of vital power that is the real cause of the weakening of life. It is through loss of vital power that the lustful man contracts horrible diseases, which are labelled as "syphilis" and treated by unlimited dosing with poisons like mercury, arsenic or antibiotics. But by Vital Economy and positive feeding these much-abused sufferers can be redeemed from the depths of incurable disease to which they are reduced by medical violence.

But of all the disciplines that are prescribed for men, the most important is Dietetic Righteousness, for the reason stated before, namely that other forms of unrighteousness arise from the constitutional defects caused by unrighteous eating. He that eats rightly is able to observe all the laws of righteousness. Indeed he is an all round righteous man as stated in the verse quoted from the Shri Bhagavatam. Food is eaten, and it eats; therefore its name is Annam, says the Taittiriya Upanishad. The significance of this text must be understood. What is eaten righteously is eaten and the end-products are eliminated, and hence health is unaffected. But if there be wrong eating, then it becomes toxic filth, which, being retained, is the cause of disease and death. The other text, which says that food is both medicine and poison, means the same thing.

Even wholesome food, if eaten in excess and without hunger, becomes toxic filth. So wholesome food must be eaten righteously. What is wholesome food is explained in the next chapter. This rule is for both the healthy and the sick. Examples have been given already in the discussion of the calorie theory, those of Luigi Cornaro, and the Brahmanas of the past ages. The abstemious eater obtains all blessings, namely health of body and mind, length of life and happiness. On the other hand the unrighteous eater loses both bodily and mental health.

The following story of one of the many experiments I made on myself will prove instructive. Once in 1915 or thereabouts I was overtaken by a nervous breakdown, for which I stopped eating and lived on tender coconut water for 15 days. Afterwards I planned to live on bananas and milk, sweetened with brown sugar—available then—for some months, for the sake of better health. At first I took about one litre of milk—two small-sized tumblers—and four bananas, twice daily. The very next day I felt great weakness and a sense of heaviness. It occurred to me to cut down the rations by half. I took only one tumblerful of milk and two bananas each time. At once the weakness and heaviness vanished and I was able to go on with this diet for about six months. This was to me a proof that when the food does not agree, the remedy will be to cut down the rations and must be adjusted to suit one’s capacity to digest and eliminate. This is how Vital Economy is to be practised. In this practise the calorie theory should be disregarded, because this theory is against the Order of Nature.

It happens that some unrighteous eaters are seemingly not seriously affected in health, so that doubts may arise as to the truth of the teachings of hygiene. These men boast of their "excellent health" in spite of wrong eating. But if scrutinised according to the science of encumbrances, given later, they would be found to be harbouring diseases in seed form, and often these men die suddenly and unexpectedly of diseases arising from these encumbrances. Also their progeny is far from healthy. We should rather look at the instances of high level health and longevity of those that live righteously, and the instances of renewed health by reform of habits according to hygiene.