You can see corn in your poop because the outside of the corn kernal is made of cellulose, a.k.a. dietary fiber, that stuff that's good for you because it isn't digested and you poop it out. Meanwhile the nutritious inside of the corn kernal has been easily digested by your body as normal.

The corn in your doody is not the nutritional content, it's the nutritional content's used empty packaging which helps clean the pathways on its way out.