Introduction
Have you ever downed a cup of coffee and then suddenly needed to make a dash for the bathroom? It may seem like a strange coincidence at first, but there is a very strong link between coffee and pooping—in fact, the two are almost inextricably linked. From the way coffee stimulates contractions in your intestines, to the classic cup of joe being used as a ‘cure’ for constipation, the science behind why coffee drinkers frequently have to relieve themselves points to a complex yet interesting relationship between the two. So why exactly do coffee and pooping go hand in hand? Let’s unpack the science behind this phenomenon.
Physiological Effects
Behind the scenes, coffee works at giving your insides a bit of a massage—literally. The coffee stimulates your digestive system, which sends strong contractions through the walls of your intestines. This encourages the muscles in the walls of your intestines to move food, bacteria and other waste through your gut and toward the rectum and anus at a faster rate than normal. This is known as gastrocolic reflex, or GCR. In some cases, the stimulation from coffee can cause the muscles in the rectum to take on wider shapes, which can give you the sensation of needing to go number two.
Effect On Stool
The act of caffeinating won’t always cause you to move your bowels more quickly, however. How regularly you drink coffee affects your stool. If you are already a regular coffee drinker, your intestines likely become accustomed to the stimulant effect, meaning your muscles won’t be as likely to contract quickly and you won’t suddenly feel the urge to use the bathroom. Nevertheless, while you might not experience a sudden urge to poop if you are a regular coffee drinker, your stool may still be affected by the drink’s effects on the digestive system.
For one, the increase pressure from the GCR stimulated by the coffee can push your stool into the rectum sooner than usual during digestion. Furthermore, caffeine can slightly increase the amount of water that is absorbed during digestion, meaning that you will likely pass less watery stools after drinking coffee.
Caffeine Content
When it comes to examining why some people feel the need to poop after drinking coffee, it’s also important to consider the amount of caffeine you’re consuming. As a general rule of thumb, products with high caffeine content prompt stronger gastrocolic reflexes and have a greater tendency to make you need to run for the toilet. Different brands of coffee have different caffeine levels, making the effects on pooping all the more unpredictable—espresso and mochas, for instance, generally have high caffeine levels, and are more likely to soak up the water in your colon and make you feel like having a bowel movement.
Eating Habits
What you have (or haven’t) eaten throughout the day can also have a significant impact on your pooping behavior after snagging a cup of Joe. Depending on how full or empty your stomach is and how often you’re caffeinating, the digestion of food can be sped up and the impact of coffee magnified. The fuller you are, the less likely your intestines will be to contract in response to coffee—however if you’ve gone a while without eating, drinking coffee might mean your stomach contents travel faster than normal through the colon, causing a GCR plus more frequent trips to the bathroom.
Conclusion
The fact of the matter is that coffee is a stimulant, and as such it affects your gastrocolic reflex slightly differently for everyone. Coupled with your unique eating habits, the type of coffee you’ve consumed and the amount of caffeine it contains, each cup of coffee can have a different impact on your pooping behavior. Therefore, if you’re someone who finds themselves a lot more regular than normal after drinking coffee, consider using it as a tool—mindful moderation is key though! It’s important to balance enjoying a regular cup of coffee with monitoring the amount of caffeine intake and considering the effect it has on your digestion.
