An inflamed colon will react quicker to any food anywhere in the digestive tract. What goes in triggers the process/peristalsis.
If you have stool in the sigmoid or it's eventually moved to the rectum, you'll have a bm. Even if it's pooled blood....
It's not the food, per se, it's the very act of eating and digestion.
You're not on rectal meds....why?
You could consider to add a fibre supplement to bulk up the stool...that could help as well.
Stress (subjective) can definitely increase bowel activity...it can also encourage inflammation if it's already festering.