What you are describing sounds like dumping syndrome. This is generally associated with small intestine resection and gastric bypass surgeries. You had lower bowel surgery so this is not a true dumping syndrome but some of the preventive measures may be of benefit to you.
Try eating several small meals throughout the day. Limit the portions of carbohydrates with the meal. Eating an apple or applesauce will help with the diarrhea. Apples have apple pectin in them which will absorb some of the excess fluid in the stool. This should alleviate the diarrhea. Immodium is available for diarrhea over the counter. Have you tried this?
Is you doctor/surgeon aware of this? Be sure you notify them of this. They may have other suggestions for you.
I hope some of my suggestions offer you some relief. Let us know if you need more assistance.