There are several elements in nuts and seeds that negatively affect your digestion. For starters, the fat content can lead to diarrhea. The high fiber may also contribute to this condition, or else create a lot of bloating and gas. However, nuts and seeds also have a defense mechanism that makes them very difficult to digest.
Certain compounds, notably phytic acid and tannin, make it possible for seeds and nuts to travel through an animal’s system relatively undigested. This gives the seeds the greatest chance of surviving to eventually sprout. It may also make the eater, in this case you, pretty uncomfortable.