Why a single cup of coffee is enough to make you go to the bathroom?

You know this situation. You finish your morning coffee, brush your teeth and get ready to leave, but suddenly your get a call from the Mother Nature. And she wants you to poop. Some people can‘t stay an hour after a single cup of coffee without dashing to the bathroom. But why? Is just a normal black coffee a potent laxative?

It actually technically isn’t. You see, caffeine is a potent diuretic. It means that it is able to drive away liquids out of your system. In other words, if you drink too much coffee, you may become dehydrated. The more coffee you would drink, the more dehydrated you would get, unless you would replenish yourself with a good supply of water. This also means that drinking coffee is more likely to cause constipation than diarrhoea, right? I mean, you should actually be facing a completely different problem, but instead you are making a trip to the bathroom.

Coffee technically is not a laxative, because it does not make your poop very soft – it does not make it hold water. In fact, it has little to do with your poop. Instead it stimulates your intestines to perform their daily dance called peristalsis. It is a rhythmical movement of the gut, pushing the poop out of the system. Peristalsis is encouraged by eating or drinking. Coffee, however, stimulates like a good full meal. Your intestines somehow are tricked into thinking that you are eating and they start making some more space for the upcoming load. And it is probably thanks to caffeine – caffeinated coffee stimulates peristalsis 23 % more than the decaf beverage.

And so material in your intestines gets pushed outwards faster, which reduces the time it stays in your gut. The problem with that is that your intestines actually absorb moisture from your poop. Because of quicker peristalsis less water gets absorbed and more stays within the material. Softer faeces, as you know, are more eager to leave your body. And that’s where that coffee effect is from.

But that’s not all. Your cup of coffee might contain some additives, such as artificial sweeteners, excess sugar and, of course, milk – all of these products also have some laxative effect. Of course, a lot of people might not even know what we are talking about this. It is because different people are affected differently by caffeine and many don’t even have to go to the bathroom just after finishing a cup of coffee. Meanwhile others are halfway through their first cup of the day and just have to go.

But what about that diuretic effect? Well, studies have shown that while caffeine is a powerful diuretic, coffee isn’t. There is around 150 mg of caffeine in a small cup of coffee and a lot of water. While caffeine may be driving water away from our bodies, it is not much more by volume than there is in that cup of coffee. Still, if you drink too much coffee, you will be dehydrated.

So now you know. When coffee is making you awake, it also wakes up your intestines and they go straight to work.