Bhagavad Gita Verse 6.16

हे अर्जुन! यह योग न तो बहुत खानेवालेका, न बिलकुल न खानेवालेका, न बहुत शयन करनेके स्वभाववालेका और न सदा जागनेवालेका ही सिद्ध होता है|

There must be a constant balance in everything a Yogi does. Eating too much or eating very little, sleeping too much or sleeping very little, for example, are not methods of succeeding in this Yoga.