I was sort of hoping you'd google diversion colitis for more information. I'll have another go at explaining it, hopefully more clearly this time and from the beginning.
The lining of the colon consists of a layer of cells called colonocytes. These cells have an important part to play in colon health. For example, they regulate fluid and electrolyte transport, regulate colonic motility, regulate cell division and growth, etc. To do all that sh!t, however, they literally need sh!t. Your sh!t. From it, chemicals called SCFAs (Short Chain Fatty Acids) are produced, which provide the fuel the colonocytes need to function. The SCFAs are produced by bacterial fermentation of indigestible fibre and starch, which digestive enzymes have not been able to break down earlier on.
Now sometimes for medical reasons (e.g. Crohn's, colon cancer), part or all of the colon needs to be surgically removed. There are many different procedures and I'm not gonna name them. But sometimes as a result of surgery, you can be left with a rectum and a part of your colon (or even your entire colon) that has been disconnected from the rest of your GI tract - that is, they have
no stool passing through them whatsoever. They are completely empty. The inflammation which develops in that isolated part of the bowel is called diversion colitis.
Diversion colitis occurs because the colon
needs stool passing through it, in order to provide fuel for the colon cells. Without the stool there is no energy, the colon cells wither and die, and colitis is the result. It's not IBD; this happens in people who have never had Crohn's or UC.
In my case I had 90% of my colon removed, with the rectum left behind. The surgeon gave me an ileostomy, which I had for two years. During that time I developed diversion colitis (or proctitis, if you prefer) in my rectum. Diversion colitis usually goes away once the colon is surgically re-connected and stool starts passing through normally again. In my case I just got more Crohn's. I had the surgery for Crohn's by the way.
So basically, in a nutshell, it's possible that stool can irritate an inflamed colon. But not having any stool doesn't do it any good either.
PS: I was basically doing intermittent fasting (although not intentionally) for many years before I had my surgery. I did purposely try to eat less, because I noticed I felt less at death's door the less I ate (eating semed to produced a strong inflammatory response whenever the food reached my lower GI tract; I was always getting fevers in the evenings and sometimes in the daytime when I was really ill). I even went on liquid and semi-liquid diets: the strictest of these involved drinking elemental liquids, which were absorbed exclusively in the upper GI tract and none of it reached the lower half at all.
None of it worked, at least not in the sense of making my disease better. Instead it just got steadily worse over the years and I eventually had to have surgery. The only reason I was able to put it off as long as I did was because of steroids but in retrospect I'm not sure that was such a good idea.
Post Edited (NiceCupOfTea) : 5/14/2017 7:12:02 AM (GMT-6)