Gastrocolic reflex:
If you’ve noticed that you often have to poop right after you eat, you might wonder if food just goes straight through you. It’s not that: It’s your gastrocolic reflex. It’s an automatic trigger in your digestive system that tells your bowels to move old food out to make room for the new. It’s perfectly normal, but it can differ between people. [Cleveland Clinic]
I shan’t share. Noted in “What you put in your coffee can have an outsize impact on your health,” Trisha Pasricha, MD (WaPo):
Leave time for a bowel movement
Have you heard of the gastrocolic reflex? It’s a physiological phenomenon by which substances enter the stomach and within minutes trigger contractions in the colon. Because of it, people often experience the urge to have a bowel movement shortly after meals, which, of course, can cause some social discomfort but is perfectly healthy and normal.
Coffee — and even decaffeinated coffee — has been found to be a potent trigger of the gastrocolic reflex in many people. If this describes you, plan your routine accordingly. Instead of chugging your coffee every morning only to sit in rush-hour traffic for the next hour, perhaps you should start sipping from a travel mug once you’re closer to your destination.
