BG 6.16

6.16 न not? अत्यश्नतः of one who eats too much? तु verily? योगः Yoga? अस्ति is? न not? च and? एकान्तम् at all? अनश्नतः of one who does not eat? न not? च and? अतिस्वप्नशीलस्य of one who sleeps too much? जाग्रतः one who is awake? न not? एव even? च and? अर्जुन O Arjuna.Commentary In this verse the Lord prescribes the diet for the students of Yoga. You must observe moderation in eating and sleeping. If you eat too much you will feel drowsy? and sleep will overpower you. You will get indigestion? flatulence? diseases of the bowels and the liver. If you eat too little you will get weakness and you will not be able to sit for a long time in meditation. You should eat neither more nor less than what is actually necessary for maintaining the body in a healthy and strong state.It may mean also that success in Yoga is not possible for him who eats more than the antity prescribed in the text books on Yoga. They prescribe Half the stomach must be filled with food a arter with water and the remaining fourth must be empty for the free movement of air. This is the Mitahara or moderate diest for a student of Yoga.If you sleep too much you will become lethargic. The mind will be dull and the body will be heavy. You cannot meditate. If you sleep too little you will experience drowsiness. You will sleep during meditation. Keep the golden medium. You will have rapid progress in Yoga.

— vedicscriptures · exposition · source ↗

Regulation of diet and sleep is recommended herein for the yogīs. Too much eating means eating more than is required to keep the body and soul together. There is no need for men to eat animals, because there is an ample supply of grains, vegetables, fruits and milk. Such simple foodstuff is considered to be in the mode of goodness according to the Bhagavad-gītā . Animal food is for those in the mode of ignorance. Therefore, those who indulge in animal food, drinking, smoking and eating food which is not first offered to Kṛṣṇa will suffer sinful reactions because of eating only polluted things. Bhuñjate te tv aghaṁ pāpā ye pacanty ātma-kāraṇāt. Anyone who eats for sense pleasure, or cooks for himself, not offering his food to Kṛṣṇa, eats only sin. One who eats sin and eats more than is allotted to him cannot execute perfect yoga. It is best that one eat only the remnants of foodstuff offered to Kṛṣṇa. A person in Kṛṣṇa consciousness does not eat anything which is not first offered to Kṛṣṇa. Therefore, only the Kṛṣṇa conscious person can attain perfection in yoga practice. Nor can one who artificially abstains from eating, manufacturing his own personal process of fasting, practice yoga. The Kṛṣṇa conscious person observes fasting as it is recommended in the scriptures. He does not fast or eat more than is required, and he is thus competent to perform yoga practice. One who eats more than required will dream very much while sleeping, and he must consequently sleep more than is required. One should not sleep more than six hours daily. One who sleeps more than six hours out of twenty-four is certainly influenced by the mode of ignorance. A person in the mode of ignorance is lazy and prone to sleep a great deal. Such a person cannot perform yoga.

— vedicscriptures · exposition · source ↗