Ayurveda suggests doing Pancha Karma at the end of the seasons to prevent accumulation of detritus in not just the G I Tract but also the entire body.
In PK you eat a specific diet for a 3 to 5 days prior to what we used to refer to as 'the holy sh*t' which is some combination (nowadays) of castor oil and or senna and or triphala ( a three fruit dried prepared medicinal).
The preparatory diet simply slows down digestion and softens, burns out and flushes the 'stuff' attached to the GIT.
This part of the process gets rid of the GIT crap and softens and lubricates it for the next process which is cleaning the whole body.
On the day of the flush you take a very hot bath. It is so hot that you have to keep a bowl of cold water next to the tub and put a towel of the cold water on your head to keep your brain from overheating causing fainting etc. Sit in there for twenty minutes and then get out and take the laxative/purgative mixture which of course results in the aforementioned HS.
Then you don't eat or drink anything except what is prescribed by the Vaidya/technician till a specified period of time has passed.
The emptying of the colon will proceed as per your body type and you count the # of evacuations and their volume and liquidity.
Based on what results you get, the next steps will be indicated in the instructions.
Eating prior to the end of the period specified will result in some serious discomfort.
It is very wise to slather on some Vaseline around you anal orifice to protect the delicate surface from being scored by the purgation process. Ie. you will have a very sore/raw asshole if you don't.
Next process is to go through the various processes to clean out your body via a number of traditional methods which are of course indicated by your body type. Use of herbs, massage, rest, quiet atmosphere, steam, enemas, etc all done in a systematic way that is done in groups of two days, ie 1, 3, 5 7, 9 etc days, basically as many as you want to have (pay for) which might be a function of your state of health or state of your pocketbook.
You come out the other end squeaky clean and very rested.
Doing a cleanse that is not apropos for your body type is a very bad idea. You can do minor to major damage, depending on what you do. Some of the colon cleanse clinics I read about make me cringe, even the ones run by Allopathic Doctors because they don't understand that different body types need different treatment.
However having said all of this, I agree with Eve and Van's assessment that the right approach is diet. Prevent the tiger before it shows up at your door.