Bhagavad Gita Chapter 6 Sloka 15 and 16

Bh.ch.6.15
Thus constantly applying his mind to Me, the yogi of a disciplined mind attains the everlasting peace, consisting of supreme bliss, which abides in Me.
Explanation
The fruit of Dhyanayoga practised as above is stated below.
A practicant of meditation should thoroughly discipline his mind as told in the previous verse.
Then he will be able to put and fill his heart, soul, mind, body, intellect and all with God and reality of God like an unbroken flow of oil.
At this stage, it is possible for him to attain the supreme goal of everlasting peace which means infinite and peerless joy that reside in God.

Bh.ch.6.16
Arjuna, this yoga is neither for him who overeats, nor for him who observes a complete fast; it is neither for him who is given to too much sleep; nor even for him who is ceaselessly awake.
Explanation
The next two verses lay down rules regarding the diet, recreation, sleep etc suited to the practise of Dhyanayoga
This is an important sloka which clears number of doubts about meditation
Meditation can be attempted by anybody
It is easy
The above verses clearly indicated the inner characteristics one has to develop
What about the physical requirements?
What should he eat, how much should he eat, how much sleep is required ---are the points discussed in this verse.
For each and every act, there are dos and don’ts –is it not?
Here the God narrates about DONT’S
This yoga of meditation does not suit to
Persons who overeats
Here one has to remember the famous saying:
One who eats only once in a day is called a yogi
One who eats twice a day is called a bogi
One who eats thrice a day is called a rogi
When it is so, what about a person who eats without break whatever he gets!!
He will eat and sleep and repeat the same. It will end in lethargy – then where is time and mood for meditation

Similarly, when one does not eat and observe complete fast , he feels strained severely in his energy, mind, senses and vital organs leading to all around depletion of energy and naturally, the practicant can neither sit steadily nor can he fix his mind on god. He cannot succeed on meditation. But after practicing for number of years, there may be possibility for this state as we see in puranas.

Next, a reasonable amount of sleep is required for a person to keep his body and mind alert and fresh.
But if one sleeps excessively, then it produces dullness and he becomes a victim of lethargy

At the same time if one does not sleep at all, what will happen?
He will never be able to overcome exhaustion of body and attain freshness.
They will result in disorders of various kinds with respect to his body and mind.

So a practicing meditationist should reasonably eat and sleep to feel healthy to carry on meditation for reasonable length of time.