How do I become more regular?

I only poop every 1-2 days. I eat alot of food, but I don't past the food until it's all been reduced to dry, very compact stools. I know the ideal stool is moist, and comes frequently. I literally eat 2 cups of cooked oatmeal every morning, I munch on the odd raw vegetable, and I eat ALOT (I mean like 2-3 pounds) of potatoes every day, as well as a lot of meat. I excercise alot, but I have been slowing down and I feel it is linked to how few bowel movements I have. I have tried Metamucil, but it literally just sat in my gut like anything else. I just felt like I had over eaten, and it took just as long or longer to use the washroom (I took the whole thing.) Someone told me that I needed to drink more water, so I have been drinking like 12 gles a day. Nothing is working and I think it is really starting to effect my energy levels. Please, any ideas will be helpful.