[In an elevated, lofty tone] Since the beginning of time mankind has had an affinity for bathroom humor.
Okay, maybe not the very beginning of time, but certainly nearly as long as humans have been creating literature and art. Keith Thomas, in a brilliantly researched essay on farting in the 17th century, shows the length and size of the obsession, and convincingly argues that it originated not with the lower classes, but with the educated elite: “From Ben Johnson to Jonathan Swift, highly educated poets turned out scatological verse; while the joke books and drolleries abounded in guns, trumpets, cracks, blasts, thunderbolts and ill winds blowing no good” (19). In the middle ages, in the medieval mystery plays, the character of the devil would often enter and exit the stage with a fart. One of the greatest poets in the English language, Geoffrey Chaucer, wrote what is perhaps the most famous and hilarious fart joke ever in “The Miller’s Tale”:
This Nicholas anon leet fle a fart,
As greet as it had been a thonder-dent
That with the strook he was almooost yblent
(Nicholas let fly a fart, and it was so loud and powerful, like thunder, it nearly blinded Absalom)
Today, the internet is overflowing and ripe with memes about coffee drinking and pooping, and there are some hilarious images to be found simply by Googling those terms. Consumers are even able to purchase any number of items around the popular meme “Coffee Makes Me Poop”, from coffee mugs, to t-shirts, bumper stickers and hats. Is there anything to this, other than infantile humor? If you are among the thirty percent (30%) of Americans who report the urge to purge after their morning joe, you may even think to yourself, with a little giggle, “It’s funny cuz it’s true”. And while surveys may be anecdotal, thirty percent is not an insignificant number. A more impressive number is eighty-three. That’s the estimated percentage of people on the planet who consume coffee daily (USA Today). Coffee ubiquitously unites us all. Or, nearly all. You know what those 17% of non-coffee drinkers are called? Unemployed! (Recent circumstances excepted.) So, how much truth is there to, or how well does science back up, the “Coffee Makes me Poop” meme?
The truth is that the ingestion of just about any digestible food stuffs, particularly in the morning, triggers a quickening in the bowels. With respect to coffee, caffeine is probably not the culprit, as these effects happen even in the absence of the world’s most popular mood enhancer. An article from Men’s Health, for instance,tells us that while caffeinated coffee is 63% more likely to cause these effects than hot water, it’s only 23% more likely to happen vs decaf. The culprit, or culprits, then, are (probably) a combination of compounds in coffee, which are, as of yet, incompletely understood.
Coffee reaches the stomach only seconds after being ingested, at which point the action begins. Scientists don’t know exactly what happens, but the theory goes something like this: of the hundreds of compounds present in a brewed cup of coffee, one or more of them triggers “the production of certain hormones in your body, such as motilin—which stimulates gut contractions—or gastrin, which causes the secretion of acid in [the] stomach” (Sgobba, Matthews). Additionally, most people drink coffee in the morning, when colons are already most active. Combine this with a little breakfast food and the sluices open up. It’s also possible that the acid in coffee may hasten the process. “Coffee has a compound called chlorogenic acid that triggers higher stomach acid levels and also higher production of gastric acid. It could be that the overall acidity bump makes the stomach dump its contents out more quickly than usual” (WAPO). Yet another idea suggests that lactose might be a culprit. Certainly, coffee alone doesn’t contain lactose, but most people (about 68%) drink coffee with some form of whitener/dairy product. With nearly 70% of the world’s population embracing the last socially acceptable form of intolerance, it’s easy to see why scientists point to dairy as a possible factor: side effects include stomach pain, bloating and diarrhea. Being lactose intolerant doesn’t mean giving up dairy altogether, however. It also doesn’t mean you’re going to shit your pants every time you have ice cream or a ‘cuppa’. For the most part, lactose intolerance is easily managed, and symptoms are usually mild, including some mild discomfort and a possible urge to poop (Mayo Clinic). Scientists are not 100% certain, but these, for now, are their best guesses as to what makes us want to poop after our morning joe.

One other component that many sources fail to mention is caffeine’s effect on the body more generally. Again, scientists have conclusively shown that decaf, and even drinking hot water, also call the colon to action. That being said caffeinated coffee does seem to have a more powerful effect, and by a significant margin. In a book called The World of Caffeine: The Science and Culture of the World’s Most Popular Drug, authors Weinberg and Bealer reveal that, “caffeine is fat soluble and passes easily through all cell membranes”, it is therefore, “quickly and completely absorbed from the stomach and intestines into the blood-stream, which carries it to all organs. This means that, soon after you finish your cup of coffee or tea, caffeine will be present in virtually every cell of your body.” (Mind officially blown!) This includes, of course, the cells of the colon, small intestine, and the entirety of the digestive tract. Better keep the porcelain gods in your prayers if caffeine is part of your morning routine.

While it’s probably true that caffeine, or coffee more generally, is not the sole catalyst that makes us poop, being the stimulant that it is, and being present in virtually every cell of our bodies, it certainly is a catalyst. It’s almost certainly more likely the case that morning activity in all forms, combined with eating and a very likely chance of being slightly intolerant to lactose, factor into the equation.
What’s the take away from all this? If you have a long commute in the mornings, don’t rush out the door with your java in hand; wake up early and give your body the time it needs to avoid suffering encopresis in your Prius, or getting a ticket because, suddenly, you have the cold sweats, goose flesh, amidst the foamy, roiling deep, and feel the need for speed—to get to the nearest loo, that is. If you find yourself in such a situation, it may seem a good idea to cut loose from some of that pressure. Rest assured, this is a mistake.
Though his hand is invisible, I want to thank Michael Formichelli for his editorial suggestions, and for contributing wit, humor, and a new vocabulary term for all of us: “encopresis”, or, for us peasants, “shitting one’s pants”.
Get out there… But not too soon
MB
Works Cited
Feltman, Rachel. “Here’s Why Coffee Makes You Poop. Washington Post. https://www.washingtonpost.com/news/speaking-of-science/wp/2015/08/10/why-does-coffee-make-you-poop/
Refermat, Emily. “The Consumer Coffee Cup.” Vending Marketwatch. https://www.vendingmarketwatch.com/coffee-service/article/12353928/the-consumer-coffee-cup
Sgobba, Christa and Melissa Matthews. “The Reason Coffe Makes You Poop”. Men’s Health. https://www.menshealth.com/health/a19547837/why-coffee-makes-you-poop/
Thomas, Keith. “Bodily Control and Social Unease: The Fart in Seventeenth-Century England.” The Extraordinary and the Everyday in Early Modern England. Angela McShane and Garthine Walker, eds. Palgrave Macmillan, 2010.
Weinberg, Bennett Alan and Bonnie K. Bealer. The World of Caffeine: The Science and Culture of the World’s Most Popular Drug. Routledge, 2002.