It is so with yoga practice as well, whether one is practicing asanas, pranayama or dhyana (meditation); the ability to attain siddhi (mastery) in one's yoga practice depends on the ability to tap and harness the prana in our body. Everything we do in the asana practice -Ujjayi breath, bandhas etc. harness the prana. The flow of prana makes the body malleable, fit for tapping into higher states of consciousness. There are many things that block the flow of prana, the chief among them is a bad diet. This is why mitahara (light, sattvic diet) is recommended for the yogi in all yogic texts that go into some details on various yogic practices.
2) The various yoga texts on Mitahara (moderate diet)
Swami Sivananda of Rishikesh pointed out, “Heavy food leads to a dull, tamasic state that induces sleep. There is a general misconception that a large quantity of food is needed for health and strength. Much depends on the power of assimilation. Most diseases are due to an unwholesome diet and overeating”.
The hatha yoga pradipika says,