The most compelling link between Yoga and Diet   in the scriptures

Even though in the last half century, our notions of a yogi are of people who are able to wrap themselves up in pretzel shapes with muscle flexibility brought about by training, and/or natural capabilities,  throughout the scriptures, the one aspect of yoga that is stressed far more than asanas is an "appropriate" and "moderated quantity" diet. The Hatha Yoga Pradipika calls this Hita Mita Ahara. 

In this article, we will see what a "moderated quantity" is and what an "appropriate" food is, as expounded in the worlds longest and what many people consider to be the greatest epic, Mahabharata. Even though it is called an epic, which by definition can also be fictional, in Sanskrit it is known by the term Ithihasa, which means "a happening that is narrated as such". This excerpt is from the Anushasana Parva (Dana Dharma sub-chapter) of the Mahabharatha. Here, Bheeshma, considered to be a great Yogi, for having conquered his senses, and for his vow of celibacy (the reason he was called Bheeshma, the one who took the terrible vow) , and the greatest warrior in the Mahabharata, instructs Yudhishtra, the soon to be crowned king, on the guidelines for ruling a kingdom, on Dharama (Virtue) and of all, most importantly, answers Yudhishtra's six questions on the nature of Daivatam (Vishnu Sahasranamam), that which is worthy of worship and the ultimate destination of a man or woman. 

On the subject of Dharma, Bheeshma, while lying on a bed of arrows pierced on his body, tells Yudhishtra about two important things if he needs to elevate himself on the path of yoga - i) fasting and eating one or at most two meals a day ii) Vegetarianism. 

1) Fasting and skipping meals periodically 

Yudhishtra asks Bheeshma, "How can one who is poor and cannot perform a Yagna (ritual worship of the supreme with oblations to a fire followed by a large donation of food and essentials to the poor and the needy), reap the benefits of a Yagna ?". Bheeshma tells him that this is achieved through fasting and eating less. This is called Upavasam in Sanskrit. Says Bheeshma, if a person eats one meal a day for a year then he/she reaps the benefit of the greatest Yagna. If this is not possible, one should eat one meal a day on alternate days. He goes on, then to say, that even eating one meal a day every 15 days and two meals a day on the other days will give significant benefits. If one eats just two meals a day for 6 years one attains a Siddhi of some kind.

References on Intermittent Fasting from the Mahabharata  

1) Section 107 of Anushasana Parva of the Mahabharata, translated into English by K.M. Ganguli, page 5261

2) Mahabharata Upanyasam in Tamil by Velukkudi Krishnan, Listen at 1:00

3) Mahabharata chapter 107 of the Anushasana Parva in sanskrit. 

2) Vegetarianism 

All texts including the Bhagavad Gita refer to meat as a "Tamasic food", i,.e. food that induces dullness and is therefore not suitable for people who are on the path of  spiritual pursuit. But what about others who are not on a spiritual path, those who are warriors or those whose work involves a lot of physical labor, don't they need meat to perform these activities  ? This is the question that comes up in the minds of most people. Read what the greatest warrior of Mahabharata, Bheeshma, says to Yudhishtra when Yudhishtra asks him, "Isn't meat required for the warrior's valor ?".

Bheeshma tells Yudhishtra that he had given up eating meat a long time back and explains why it is not desriable to eat meat not just for the yogi on a spiritual path but for everyone else also. 

"Well-dressed, cooked with salt or without salt, meat, in whatever form one may take it, gradually attracts the mind and enslaves it. How will those foolish men that subsist upon meat succeed in attaining finer states of mind", says Bheeshma.

"By committing a slaughter, one becomes guilty of it. By inciting others to it one becomes guilty. By mentally committing an act of slaughter, one becomes guilty of it. By eating meat, one feels the desire for meat increasing. A taste or predilection for meat is thus created. Hence, the best course is total abstinence."

"There is nothing on earth that is superior to flesh in point of taste. There is nothing that is more beneficial then flesh to persons that are lean, or weak, or afflicted with disease, or addicted to sexual congress or exhausted with travel. Flesh speedily increases strength. It produces great development. But, O delighter of the Kurus, the merits are great that attach to men that abstain from it. Listen to me as I discourse to thee on it. That man who wished to increase his own flesh by the flesh of another living creature is such that there is none meaner and more cruel than he. In this world there is nothing that is dearer to a creature than his life. Hence (instead of taking that valuable possession), one should show compassion to the lives of others as one does to one's own life. "

3) Conclusion

Thus spake Bheeshma, the one who took the terrible vow (of celibacy), he who was given the boon of leaving his body at a time of his choice, he the longest lived of the Kuru dynasty. The exposition of Bheeshma to Yudhishtra, the then soon to be crowned king, on all aspects of life and ruling a kingdom in the Dana Dharma Parva (Chapter on Charity and Virtue) of the Anushasna Parva  (Chapter on Resuming the rule) is considered to be one of the greatest collection of guidelines and rules for living.

Bheeshma, the one who could not be conquered, decided it was time to give up his body on the battlefield and gave this exposition while lying severely injured on a bed of arrows, and waited for Uttarayana, the right time to depart his body.