I'm IBS-C, too. If I eat lots of rice, bread, & potatoes, it makes me worse too. But I noticed that some of Heather's pointers do help me-- like staying away from dairy products & red meat & by eating low fat foods.
Diet alone has never helped me to be "normal." I have to take Miralax and occasionally Zelnorm to feel more normal. And I still have boughts of cramping, gas, &/or C even though I take those. But I have lots more good days than bad days!