Peace be to you
Bretherin when we fast from something, we desire that which we obstain from, especially if we fast for great periods of time.
If we fast from ice cream and we walk down a road with ice cream pallers we will crave that which we gave up.This is the Flesh.
After fasting for long periods of time you will fufill the verse paul speaks of,being content in any state we are in, with Gods help of coarse.
In romans7,Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth?Wherefore, my brethren, ye also are become dead to the law by the body of Christ; that ye should be married to another, even to him who is raised from the dead, that we should bring forth fruit unto God.<-------------------We die with Jesus to Flesh
These chapter explains the actions of the flesh in all of us;
http://www.kingjamesbible.com/B45C007.htm
But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.
In james,4
From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members?Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not.Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts.
Therefore to him that knoweth to do good, and doeth it not, to him it is sin.
heb,5
sin dwelleth in us all,Ask for revelation on romans7,Remeber the Godhead here.
Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.
Love a friend in God