I started having problems about 10 years ago. after a couple years I realized I had developed an intolerance for lactose. It wasn't too bad. I could drink milk or eat ice cream, but I couldn't have anything with cheese or cream sauce or anything like that (macaroni and cheese was one of the worst!)
Eventually, the intolerance went away after I was sick and didn't eat any dairy at all for a week. But after that, I would still experience times of being very irregular. I would eat something that didn't even have dairy in it and then have horrible stomach cramps and have to run to the bathroom. I alternated between almost-constipation and very loose stool. It's been worse in the past year, though. My lactose intolerance is coming back, but even when I don't eat dairy, I still get those stomach cramps when I'm almost finished eating or even a couple of hours after eating. Sometimes I get them right after drinking a glass of water!! And no, it's not cold water. When I was a kid growing up, I used to go to the bathroom every 3 days. Now I usually go every day, sometimes up to 3 times a day (with cramping every time). I don't think it's a specific food (besides dairy, which I try to avoid now) that gives me those lower abdominal cramps, since I get it even when I drink water sometimes.
Oh, another thing I've experienced a few times in the past year is what seems like a soreness in my colon. It get a dull ache in the middle of my lower abdomen that almost feels like period cramps, but when I sit, it's like I can feel it get worse with pressure on it.
Aah, my brother has Crohn's. Sometimes I wonder if I have it, but his symptoms seem a lot worse than mine. Plus when he had his first major flare-up he lost 80 lbs. I haven't had any weight loss. I'll look into it, though.