If You Need to Poop Right After Eating, Here’s Why

Erica Sloan
·11 min read

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Arguably one of the worst times to feel the urge to poop is in the middle of a meal or when you’ve just wrapped up. No one wants to deal with literal crap when the taste of, say, eggs or enchiladas still lingers. Not to mention the potential inconvenience of pooping right after eating if you’re having that meal anywhere outside of your home. But in your body, ingesting and excreting are intrinsically linked—opposite ends of a single GI tract. And putting food in your mouth can be the very thing that prompts waste to shimmy its way out.

This natural response is called the gastrocolic reflex: Filling your stomach automatically stimulates movement in your large intestine, or colon, which can give you that urge to go in as little as 15 minutes. “This is a normal way that our bodies are hardwired,” David Kunkel, MD, a board-certified gastroenterologist and codirector of the GI motility and physiology program at UC San Diego Health, tells SELF. He compares it to the patellar reflex. If you tap someone below their kneecap, their thigh muscle will contract—and just as reliably, if you eat something, your colon will start squeezing, he says.

How quickly and intensely that reflex happens, however, can vary. While some people might not sense the gotta-go feeling until a while after their last bite, others are interrupted by it mid-meal, “which can be very bothersome and interfere with quality of life,” Dr. Kunkel says. Read on to learn why the gastrocolic reflex happens, when it might kick into overdrive, and how to deal if it seems to strike at the worst possible moments.

The gastrocolic reflex makes you poop to create room in your intestines for the food you’ve just eaten.

The short timespan between eating something and pooping can make it seem as if the food you’ve just consumed is slipping right through you—but “the truth is, it takes a lot longer for things to move through your gastrointestinal tract,” Kyle Staller, MD, a board-certified gastroenterologist and director of the GI Motility Laboratory at Massachusetts General Hospital, tells SELF. Snaking through your colon alone can take more than 24 hours, he says. (ICYWW: The full length of your small and large intestines is upwards of 20 feet.)

Instead, pooping right after eating is more so the result of a chain reaction. As you eat, your stomach fills up and expands to make room for more food to gain entry. At a certain threshold, “stretch receptors in the wall of your stomach sense its increasing size, and that creates signals within the autonomic nervous system, which connect to the colon, causing rhythmic contractions,” Dr. Staller explains. Once that squeezing begins, all the food remnants in your colon (leftovers from meals you ate in the previous couple days) get moved along—and when that waste creeps closer to your butt, you get the urge to poop, he says. Your body’s goal with this process: push out the contents sitting in your colon to create space for the food heading its way.

The gastrocolic reflex is thought to be most powerful in infants, who tend to eat more often and have less control over their pooping tendencies. As we grow up and enter situations where it’s not so cool or convenient to have a bowel movement post-meal, we may subconsciously suppress that reflex, Dr. Kunkel says. But ultimately, it’s natural (and necessary) for the colon to get active after you eat.

If you get the urge to poop immediately after a meal, you could have an overactive gastrocolic reflex.

Sometimes, the normal reflex that prompts you to poop after eating can get exaggerated to the point where it really disrupts your life. For instance, the feeling regularly strikes when you’re mid-meal, hits you with such urgency that you might not make it to the bathroom, or triggers abdominal discomfort or cramping. Research suggests that all of the above is most typical in folks with irritable bowel syndrome (IBS), a condition marked by a set of GI symptoms that overlap with these, like bowel changes and pain with pooping. In particular, those with IBS-D (or, diarrhea-predominant) and IBS-M (or, mixed—meaning, both diarrhea and constipation) may have an overactive gastrocolic reflex, Dr. Kunkel says.

The factor linking this hypersensitivity and IBS? The nervous system. What causes IBS isn’t totally understood, but researchers suspect that it involves a glitch in communication between your gut and brain, meaning certain nerves that exist in either organ or along the path between the two are misfiring, Dr. Staller explains, setting off sensations of pain, discomfort, and bloating even though there’s nothing structurally wrong in the GI tract. In someone whose gut-brain interaction has gone haywire, it follows that the gastrocolic reflex—which also relies on nerve signals—may be on the fritz too, perhaps becoming abnormally sensitive, Dr. Staller says. In other words? The threshold for triggering this reflex may be lower in some people with IBS, Dr. Kunkel explains, so even a few bites of food could rev up your colon and spark an urgent, uncomfortable need to poop. (The reverse might occur in someone with IBS-C, or the constipation-predominant subtype: You’re more likely to have an underactive gastrocolic reflex that makes it tough to poop, Dr. Staller notes.)

The mind-gut link can also explain why your gastrocolic reflex might really act up when you’re stressed. As you eat food and nerve signals start telling your colon to move, your brain can either interpret that sensation as NBD, or it can panic and say, “‘Hey, I’m getting bad data from my gut, and I need to find a bathroom ASAP,’” Dr. Staller says. The latter option is more likely if you’re emotionally on edge. From that point, he says, it’s easy to get stuck in a negative feedback loop: The more you worry about gut discomfort or urgency, the more attentive you become to it…and the more potent it can feel in return. “I like to think of stress and anxiety never as the cause of any of these symptoms, but really as the volume control among those people who are probably already wired for trouble,” Dr. Staller explains.

Beyond an overeager gastrocolic reflex, there are a few other GI scenarios that could send you straight to the bathroom post-meal, such as food poisoning or a food intolerance (for instance, to gluten or dairy). In these cases, though, you’d likely wind up with urgent diarrhea, as your body is either fighting a pathogen or struggling to digest certain nutrients, respectively. (You’ll want to see a doctor if you’re experiencing diarrhea that persists for several days, blood in your stool, or symptoms of dehydration.)

Here’s how to tame an overactive gastrocolic reflex and calm the urge to poop right after eating.

It’s worth reiterating that it’s perfectly normal to have to poop after eating—and if you aren’t bothered by it, there’s absolutely nothing you need to do about it. But if, on the other hand, your bowel is yanking you away from the dinner table mid-conversation or just making it tough to comfortably finish a meal, know that there’s plenty you can do to pacify your gastrocolic reflex. Follow these tips whenever you’d like to avoid a post-food deuce.

Cool it on the coffee

Aside from making you more alert, coffee is perhaps best known for its poop-inducing powers—and that’s exactly what we’re trying to avoid here. Research shows that coffee has a direct effect on your colon, triggering those contractions that push waste along in as little as four minutes. Hence, the record speed of the coffee shits.

Studies have also found that caffeinated and decaffeinated types can spark that movement, Dr. Staller says. Researchers think that certain coffee compounds prompt the release of hormones like cholecystokinin that supercharge the gastrocolic reflex. In any case, you’d do best to steer clear of anything coffee-containing if you’re looking to slow things down.

Eat a bunch of smaller portions, versus fewer big ones

As Dr. Kunkel puts it, “volume matters.” The greater the quantity of food you’re sending to your stomach at a given time, the more space it’ll take up there, and the more stretch you’ll create—which is what sets off that reflex in your colon, he explains. To be clear, this isn’t to say eat less. But eating smaller meals more frequently might keep your gut from hitting that trip wire as often, Dr. Kunkel says.

Go easy on the high-fat foods

Don’t get us wrong: Fats are an integral part of any diet, playing an essential role in your brain and nervous system functioning and helping you absorb fat-soluble vitamins that support your bones, teeth, hair, and skin. But it’s also true that eating a whole bunch of them in one meal can send your gastrocolic reflex into overdrive.

That may be, in part, because fat is calorically dense (meaning it contains more calories per gram than the same amount of carbs or protein), which causes it to empty more slowly from your stomach, Dr. Kunkel says. More food filling up your belly for longer just ups the chance that you flip on those stretch receptors and trigger things to get moving farther down in your colon.

It’s also possible that certain components of fats, much like coffee, may stimulate the release of cholecystokinin and other hormones that play a role in the gastrocolic reflex—making it all the more likely that a high-fat meal sends you straight to the toilet. Again, that’s not to say that you should avoid fats entirely, Dr. Kunkel emphasizes. Instead, he suggests experimenting to figure out what amount seems to cause symptoms for you.

Turn to medication

In some cases, changing what or how you eat might not have much of an effect. After all, we’re talking about contractions in the muscle of your gut that you can’t directly control. That’s where antispasmodic medicine might come into play, Dr. Staller says. These meds, which include dicyclomine (Bentyl) and hyoscyamine (Levsin), can help calm down your colon muscle so it isn’t squeezing so hard—and pushing things out so quickly.

Dr. Staller often suggests people take anti-spasm drugs before entering a situation where they really want to avoid a poop emergency. “The hope is that the gastrocolic reflex still happens but in an attenuated way, so that they’re able to at least delay their symptoms to a time when it’s more socially acceptable to run to the bathroom,” he says.

Because these drugs require a prescription, you’ll have to see a primary care doctor or gastroenterologist if you’re interested in this approach. They can help you weigh the benefits with potential side effects (which include dizziness and headaches) and choose the option that’s best for you, given your health history and any other drugs you’re taking.

Seek out longer-term IBS care

A doctor can also help you determine if your post-meal urgency is tied to IBS—and if so, whether it might be a better tack to treat the condition more broadly. That might look like implementing other lifestyle adjustments (such as shifting to a diet that’s low in hard-to-digest carbs, doing more aerobic exercise, or engaging in stress-reducing tactics), or taking a type of antidepressant called a neuromodulator (e.g., Elavil or Norpramin) that helps “turn down the volume on abnormal nerve function,” Dr. Staller says.

There are also plenty of effective non-drug interventions, he adds, like cognitive behavioral therapy for IBS and gut-directed hypnotherapy, both of which address the connection between your gut and brain and aim to change how you respond to symptoms. (Your doctor may be able to refer you to a GI-focused therapist or psychologist who offers one of these treatments, or you can search for one near you in this database.)

Ultimately, the gastrocolic reflex is “often one part of the larger IBS symptoms complex,” Dr. Staller says, “and treating the bigger picture can be very effective at making these gastrocolic reflex issues go away as well.” This kind of care won’t offer in-the-moment relief, but over time it can reduce your likelihood of having an ill-timed urge to poop in the first place.

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Originally Appeared on SELF

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