Why does drinking coffee in then morning sometimes cause immediate evacuation of bowels and/or bladder and other times have no effect?

Question

I know that coffee is a diuretic but I don’t understand why the effects can vary so much day to day

In: Biology

Answer 1

coffee triggers the release of cholecystokinin; which tells the body to make the lower GI work. since most people will normally have to poo in the morning, coffee drinking can facilitate the urge and bodily actions

since most people do not poo in the evening, there is nothing to evacuate when the lower GI is triggered with that after dinner coffee