I've had IBS my entire life. I had IBS-D until I was about 21 when, over about a 2 week period of time, it changed to IBS-C. I'm now 31 and I've dealt with IBS-C for the last 10 years, getting progressively worse. I mean worse to the point that I usually would only have a movement once every 7-10 days. Regardless of exercise, water intake, fiber, probiotics, trying to go, etc.
I became interested in elimination diets and books about IBS last year and learned from my IBS books that IBS is not one diesease, but a collection of similar symptoms. Often it is unidentified food intolerances (like lactose intolerance). People can be intollerant to just about any food or family of food. That discovery led me to start reading about elimination diets, with the intention of doing one to discover what intolerances may cause my IBS. Unfortunatly (or fortunately), what I discovered is that birth control can have unforseen effects on the body, like in my case, causing my IBS to change from D to C. Multiple books recommended getting off birth control before attempting an elimination diet because that could be all that is causing the problems. After reading everything I could find on the topic for about 6 months (this seems to be a debated topic), I asked my doctor to change my birth control to something with less hormones. It was a difficult decision because I had had problems with other birth controls in the past and the one I was on was awesome for me. Dependable, light, no spotting. I hated to change. My doctor encouraged me though and said that it could absolutely be a cause. After a month I can tell you it was the right decision. I am trending back towareds IBS-D, but I have movements at least every other day now, even if they are urgent. I am much happier. When I stabilize, I think I will start an elimination diet, because, obviously I still don't have normal digestion, but at least I'm getting back to how God made me.
I know that this is only my experience, but I just wanted to put it out there for everyone else to know about. My experience may help you or not, but at least you can be informed.
In the long run, we shape our lives and we shape ourselves. The process never ends until we die, and the choices we make are ultimately our responsibility.--Eleanor Roosevelt