Miss CC-I think it's a little bit of both, but if you have researched as much about gluten and grains as I have, you would see gluten is very damaging to the intestinal wall and creates inflammation in many people (for many people they don't even know it until longterm it creates problems).  Gluten and other grains are not easily digested and can deplete us, not to mention wreaking havoc on the pancreas and blood sugar dance that goes on in our bodies after we eat.  Since our guts are "leaky" the grains and proteins in gluten aren't properly broken down and they leak into our bloodstream creating an inflammatory response by the immune system. Cutting it out helps to calm down the immune system so it can help restore balance and heal inflammation in the body (such as our bladders).  We IC'ers avoid bread to help starve the yeast mainly and some believes that, after our guts are healed, one may go back to consuming those foods in moderation. My plan it to be gluten free for life, even though I know I may tolerate it better as time goes on.  I have altered my lifestyle enough to where I do not need it, crave it, or want it due to the risk of creating more imablance and inflammation.  Not to say bread causes IC, that is not at all what I mean, but the gluten and yeast exacerbates the gut imbalance and bogs down the immune system, as well as the liver, spikes insulin and impedes digestion. I think many of us will struggle with the "potential" for yeast overgrowth for many years, although we may be back in balance and symptom free. Eating yeast, to me, seems like not a great idea once I've healed. Breads are also very acidic in the body and since keeping a healthy pH balance is critical for us, I prefer to get my acid from meats and occasional rice and potatoes and balance with loads of veggies, which are alkaline. Hope that is helpful.