Gemd,
So this is my opinion and in no way based on fact, just experience. I've had an ileostomy for 23 years now. If you understand how a stoma is formed, it might make more sense. The contents of the small intestine are more liquid like and still have some stomach acid. The large intestine would soak up the water/acid in the waste, making more solid poo's.
Think of it this way. An ileostomy stoma is formed by pulling your small intestine through the abdomen wall, cuffed or folded like a shirt sleeve and then sewn to the abdomen. Before the surgery, my small intestine was used to just free flowing waste going into the large intestine. But when the stoma is formed, the ability for the waste to flow freely is basically cut into half if not more because of a smaller opening for the waste to get out. Not to mention, your body naturally tries to close the hole or wound through your abdomen that the stoma is sticking out of. This is another reason why second surgery's are sometimes required to relocate the stoma site.
Because the hole in a stoma is smaller, it has a harder time passing larger chunks of food that weren't thoroughly chewed up like corn, peanuts or naturally fiberous foods. And when your body is trying to process naturally fiberous foods, they can start backing up insided the small intestine because the stoma can't get the food out fast enough, causing obstructions and/or blockages and of course the pain that comes with it.
So to avoid the risk of getting an obstruction/blockage, ostomates have to learn all over again on how to properly chew their food. No more woofing down food. The more the food is broken down before it reaches your stomach the better. You'll absorb more nutrients from it as food is fuel, you will actually get that "full" feeling faster and you will substantially reduce the risk of forming obstructions/blockages.
Again, this is just my opinion/experience. Hope it helps.
Bain