Diet

The foods you mentioned are considered "ruffage" and are extra fibrous (not necessarily high in fiber though) and that makes them much harder for the body to digest. We are supposed to avoid them after surgery to give the intestines a break while we heal. These types of foods are more likely to cause blockages as well and often cause more gas which is more painful right after surgery not to mention just plain old annoying. So they don't cause constipation or diarrhea (although leafy greens cause me diarrhea) its just a matter of fibrous matter being unkind to healing tissue. Since they can cause blockages, they should be reintroduced one at a time so you can see how they affect you and remember to chew really well.