People on the Keto Diet Have All Kinds of Problems Pooping

The high-fat, low-carb ketogenic diet can lead to constipation and diarrhea.
October 8, 2018, 9:18pm
Eldad Carin/Stocksy

If you’ve ever tried the ketogenic diet—that high-fat, low-carb, “miracle” diet—you’ve probably found yourself in one of two camps:

Camp number one: Those who can’t poop.

Camp number two (pun intended): Those who can’t stop pooping.

I know because I once spent four months on the diet and, well, dear readers, I was in camp one. And it was a strain.

Here’s the thing though: Because many of us go keto based off the advice of our friends, not off the counsel of our doctors, it’s not our doctors we consult when things go south (or, ahem, won’t). Instead? We turn to our friends. But not our real-life friends. Oh no—too mortifying.


Instead we type “how do I make myself stop/start pooping” into the search bar and wait for Dr. Google to dispense its advice. Here’s a Google Trend graph of “keto constipation” and “keto diarrhea” queries in the US over the past five years. (It would appear that more people are dealing with diarrhea than constipation.)

Screenshot: Google Trends

“As the moderator of the popular Facebook support group ‘Dirty, Lazy Keto,’ I receive all sorts of private messages from followers that are too embarrassed to post their concerns to the group,” says Stephanie Laska, the author of Dirty, Lazy, Keto: Getting Started, How I lost 140 Pounds. “I’ve realized that everyone loves to document and share photos of every meal with the message board, and on the opposite end they become embarrassed to talk about bowel movements or constipation.”

Laska personally struggled with bowel issues when she started on Atkins, which allows fewer veggies and advocates for more protein than keto. Atkins also has many packaged meal and bar offerings, which Laska says really gum up the whole system. Now that she’s eating a modified keto diet, which includes a lot of low-starch veggies like spinach and kale, “I’m proud to share my bowel movements are healthy and regular,” she says.

Which made us wonder: Is there anything wrong with eating lots of fat and protein and very little fiber? Should we be concerned that a trendy diet people are supposedly doing for their health has a side effect so common that it’s spawned entire threads (massive poops! pencil poops! poop potions!) on Reddit? And, how solid (SNORT) is the advice that these groups are giving?

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Here’s the good news: Constipation isn’t going to kill you. “Being constipated is not carcinogenic or anything like that,” says Nitin Ahuja, a gastroenterologist and assistant professor of clinical medicine at Penn Medicine. You could live out the next 15 years of your life grunting it out on your porcelain throne and that alone wouldn’t cause any major issues, though constipation of can lead to hemorrhoids—which are engorged rectal veins that can be provoked with the pressure of straining and worsened by passing hard stool. And you might be walking around feeling like a plugged-up firehose 24/7, so there’s that. (Ahuja says he hasn’t seen people on keto coming in for poop help, but he wonders if that’s related to the fact that the diet isn’t supported by many in the medical community, and patients may not be telling him about their fat-first eating habits.)

While constipation isn’t dangerous, Ahuja has other concerns about the keto diet’s effects on your gut. For one thing, chronic constipation is likely a symptom that you’re not getting enough fiber. Fiber makes you poop. There are two types of fiber: Soluble fiber adds bulk, while insoluble fiber draws water into the stool and helps accelerate its movement through your intestines, Ahuja says.

“We know from epidemiological studies that high-fiber diets seem to be protective against colon cancer,” he says, adding that we also know that high levels of meat consumption can be a risk factor for the disease. Especially processed meats, like bacon, which is a favorite keto food. Of course, these studies just show correlation, not causation, so we can’t yet say for sure if it’s the meat or the fiber causing the risk or the reward.


Ahuja also worries about what a drastic diet change does to your microbiome. “I get hesitant to make comments on the microbiome because a lot of what we know is still based on speculation,” he says. However, recent studies have shown that people on the FODMAP diet, a research-based protocol for managing irritable bowel syndrome (IBS), can have shifts in their microbiomes in just three to four weeks. Ahuja can’t imagine a scenario where that’s not also the case on the keto diet. Why does that matter? While research is still in its really infantile stages, there’s some evidence that the microbiome plays a role in your immune health, your metabolism, and possibly even in your mental health.

Ahuja says the most common constipation remedies he sees bandied about online aren’t dangerous. Laska, for example, usually recommends that people get off the “keto junk food,” like super-processed bars and cheese for every meal. “The bottom line is that you can’t game the system. There are no loopholes with a keto diet. You have to make your carbs count in the healthiest way possible,” she says. If adding more kale or broccoli (two low-carb veggies with tons of fiber) doesn’t do it, adding things like flax or chia seeds may help, too, she says. (However, for the strictest of diets, chia seeds may take up a good chunk of your carb count for the day.)

That’s the advice that Rebecca (last name withheld for poop privacy reasons) from Durham, North Carolina, got last year when she tried out the diet. “I tried making some chia pudding but it’s kinda gross when you can’t properly sweeten it,” she says, adding, “I also considered drinking psyllium husk in almond milk, but the taste is nasty.”

In the end? She gave up on the diet. Not just because trying to poop was like a daily cardio session, but because she had less energy during her workouts, and she had to limit some of her favorite kinds of produce. “In reality, keeping net carbs to 50 grams or less is pretty disheartening for a banana-, fruit-, tuber-, and root veggie-lover like me.”


Then, of course, there’s the other side of the keto-poop coin: The folks who get the runs. These people are probably overwhelming their bodies with fat, Ahuja says. If your pancreas can’t break the fat down fast enough, you’ll end up with diarrhea. The solution in that case is simple: Slow your roll on the butter, bacon, and MCT oil (that stands for medium-chain triglycerides; it's what people put in Bulletproof Coffee, alongside the butter). Again, Ahuja says that short-term loose stools are probably not dangerous, but are definitely annoying.

The takeaway here is that it’s probably not a horrible thing if you get your keto pooping advice from the Internet. However, Ahuja gives two stern warnings. You should see your doc if you can’t poop without using stimulant laxatives—which are something Ahuja likes to keep his patients away from because they can be habit-forming and may reduce your colon’s ability to do its job naturally if taken long-term. “The most common stimulant laxatives are bisacodyl and senna,” he says, adding that if you’re not sure what you’re taking is safe, talk to your doctor.

The second is that abusing laxatives has consequences. “I worry that the type of person who is likely to adhere to a really strict keto diet may also be the type of person who is likely to abuse laxatives.”

Finally, if there’s a sudden change in your ability to poop, know this: It may be a structural issue versus a dietary one. That’s something strangers on the Internet can’t help you diagnose. And please don’t let them try.

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