6.16 (Tu, but) O Arjuna, Yoga na asti, is not; atiasnatah, for one who eats too much, for one who eats food more than his capacity; na ca, nor is Yoga; anasnatah, for one who does not eat; ekantam, at all. This accords with the Vedic text, 'As is well known, if one eats that much food which is within one's capacity, then it sustains him, it does not hurt him; that which is more, it harms him; that which is less, it does not sustain him' (Sa. Br.; Bo. Sm. 2.7.22). Therefore, a yogi should not eat food more or less than what is suitable for him. Or the meaning is that Yoga is not for one who eats more food than what is prescribed for a yogi in the scriptures on Yoga. Indeed, the antity has been mentioned in, 'One half of the stomach is to be filled with food including curries; the third arter is to be filled with water; but the fourth arter is to be left for the movement of air,' etc.
Similarly, Yoga is not for ati svapna-silasya, one who habitually sleeps too long; and Yoga is na eva, surely not; jagratah, for one who keeps awake too long.
How, again, does Yoga become possibel? This is being stated: