It's not just in your head; that rush to bathroom after drinking a cup of coffee is real. Coffee can definitely get our bowels moving, and knowing why coffee makes you poop can help you better plan your morning (a coffee trip after an early meeting or exam might be smart). It's perfectly healthy to go to the bathroom a couple times a day, so drinking coffee can actually be beneficial for maintaining regular bowel movements. The tricky thing about digestion is that sometimes the body can act up, leading to pains, cramping, soft stool, or constipation, and unfortunately there are some serious effects of coffee on digestion that are to blame for tummy troubles. 

"Your colon is a muscle, and since caffeine stimulates muscles, caffeine intake can stimulate peristalsis––the rhythmic contractions of the GI tract. This can result in diarrhea or loose stools for some or a comfortable bowel movement for others," explains Lori Chong, registered dietitian at The Ohio State University's Wexner Medical Center.

"Coffee has caffeine, and caffeine can boost your metabolism. Caffeine can act as a laxative. This is why drinking coffee can cause some people to have a bowel movement not long after consumption," explain Dr. Charles Galanis, a Board Certified Surgeon in Chicago and Robert Dorfman, Research Fellow at Northwestern Division of Plastic & Reconstructive Surgery. 

However, the opposite can be true as well. "Caffeine can act as a diuretic and increase urine production, thereby conceivably contributing to dehydration and possible constipation as a result," Galanis and Dorfman say.

So, where do we go from here? 

Drinking coffee will affect digestion, for sure, but taking these measures can reduce the likelihood of such bowel extremities. "It is therefore important to have adequate water intake to avoid such problems," advise Galanis and Dorfman. Plus, digestion can slow when drinking coffee. "Caffeine has also been shown to increase production of hormones like adrenaline and noradrenaline, which give you the sensation of more energy and cause your heart to beat faster. In doing so, this can decrease blood flow to the intestines, thereby slowing the process of digestion," Galanis and Dorfman explain.

As with most tasty, godly things in life, moderation is key when it comes to coffee. "Ultimately, caffeine is acidic, so be careful not to consume too much of it, or you may potentially damage the lining of your digestive tract. Too much caffeine consumption may induce ulcer formation and inflammation of the gastric wall, and this may be particularly bad in patients with Crohn’s disease or irritable bowel syndrome," warn Galanis and Dorfman.

Keeping in mind all the science behind coffee, as long as you're mindful of intake and know your body, there's no reason to forgo that glorious jolt.