too much can, and if you aren't used to eating it and then suddenly add it, it can
However, fiber helps you stay fuller, longer & takes up more space in the stomach while the other type keeps you regular. There's soluble and insoluble fiber....
My fiber intake is high right now (about 50 to 60g per day), lots of oats and veggies. The first couple of weeks were ridiculous, I took so many trips to the rest room. I think I am finally adjusting.