I would like to start with advising that you should be checked out by your family practitioner prior to attempting to fast. 

   

It is best to start with the fasting aspect prior to any other discipline since it ties in all of the others. Understanding by practicing  will give the practitioner insight as opposed to a full belly. As your belly grumbles your senses will change.  It has been proven that one can survive without food for about three weeks and water for about three days. I cannot think of anyone including myself, who could not stand  to lose a little weight.  Fasting also gives the intestinal tract a break allowing it to cleanse itself of impurities. As long as you have clean water you will be fine for a good amount of time and food should be placed third in survival needs.
    Fasting has been practiced by many cultures since the beginning of the history of man but now alternative ways of cleansing our systems has reared its ugly head.  Some of these techniques/systems/herbal remedies have become popular because they can be done within minutes (swallowing a pill) as opposed to days of fasting. Enemas are one approach that have been popularized as a natural detoxifyer and cleanser. 
Some of these companies push different ingredients to attain a "deeper" cleansing like coffee grounds. The lower intestinal tract is very vascular and bypasses the liver (1st pass) which is how the bodies detoxifies and protects the system from poisoning. Many types of drugs can be administered this route for different reasons. It can also be the route of choice for addicts who are unable to use  the oral route or are looking to minimize the breakdown of the drug as it is being detoxified by the liver in the oral route.  Since this route bypasses the liver chances of over dosing increases dramitcally.  This can lead to lethal doses very quickly as a couple had experienced when a wife convinced her alcoholic husband to try since the medications he was taking were contraindicated with alcohol. He died later that night.

There has also been reported a trend where college students were ingesting alcohol via the rectal route. This new trend called "Butt Chugging" is very dangerous. The large colon is designed to reabsorb the liquid out of stool matter but when alcohol is infused  a person can increase their blood alcohol content by 5 times with ease since it bypasses the liver avoiding it from being filtered.  I felt it necessary to add this into this piece because of the lethal alternatives people might try out of disinformation. Now let's get back to the subject of fasting.

     First, fasting brings forth those primal feelings that one with a full belly could never comprehend. What is your state of awareness having overindulged yourself after a Thanksgiving meal? Are your senses as acute as before when you were waiting for the table to be set? Can you smell better when your are hungry or when you are full? What is the longest you have gone without having anything to eat ?  How acute is your sense of smell when you are very hungry? In what state do you feel most alive? With a full belly or an empty one? Fasting stimulates hunger which heightens the awareness of the practitioner of sights, sounds, smells as well as themselves and their environment. It is believed to be a primal mechanism to of helped our ancient ancestors to be more successful hunters.  It is always within us but becomes conscious to us in times of need.  It is in this state of consciousness that the practitioner can get a better perspective of how the wilderness really is.  By continuous practice and recognition of  being in this state the practitioner can then move on to the next phase which is the fundamental and instrumental part of living WITH the wild and not IN the wild.   Awareness