Set the alarm to "snooze" a few times, roll out of bed, and most people's first thought will usually be, “damn I need a coffee.” A familiar routine? Well you may also be accustomed to the sudden need to use the toilet pretty swiftly after your first coffee too – but why does coffee make us need to poop so bad?

Caffeine is normally fingered as the culprit to this sudden intense urge to use the restroom, but most of us don’t experience the same urge after a Coke or Mountain Dew. So what’s different about coffee?

Scientists aren’t entirely sure which of coffees’ 2000 compounds cause a laxative effect, and so quickly, but what they do know is what the mystery chemical is doing to the body to bring about the effect. It will be increasing levels of certain compounds such as gastrin, which is found in the colon, and cholecystokinin, a compound which regulates how often we go.

And according to ACSReactions, only a third of the population experience this effect from coffee – a lot less than one may expect!