Poo is what your body doesn't need from the food you eat. Poo is food you ate that was either impure (which affects the color) or indigestible (which affects the shape/consistency) or simply a result of eating more than your body needed for physical sustenance. Fiber, incidentally, is indigestible material. Vegetables have a lot of fiber. Meat does not. How your body reacts to these different types of foods has a lot to do with your blood type. There are other factors as well, like carbohydrates—which digest in your small intestine, and proteins which digest in your stomach (which is why it's not a good idea to mix large amounts of protein and carbs—your proverbial meat and potatoes). So, you eat food of different kinds, it digests in different ways, and then what is left over ends up in your colon where the remaining fluids are drawn from it, turning digestive soup into solid poos. The amount of water and other liquids you drink will affect things greatly. The physical shape of your colon, determined largely by your breathing and exercise habits and posture and tension level, will then manufacture a unique and exciting poo. I bet the butthole, much in the way a PlayDoh toy works, shapes things some too. That's my basic understanding of the whole poo-nomenon." —Slap Maxwell, Sakebomb