For a dietitian employed in a gastroenterology practice, the low FODMAP dietis easily one of the most effective tools I have for managing a variety of digestive symptoms, from bloating and abdominal pain to excess gas and diarrhea.
For people with Irritable Bowel Syndrome (IBS) in particular, the low FODMAP diet has a very high success rate: some 70% of individualsexperience marked improvement in their symptoms on the diet.
And once the Elimination Phase offers ‘proof of concept’ that your symptoms are worsened by one or more high FODMAP foods, you can proceed with systematic challenges to identify which families of FODMAP—and in what quantities—aggravate you personally, such that you need only restrict your diet of those foods that trigger symptoms.
When The Low FODMAP Diet Is Not Enough
Stool Burden and the Low FODMAP Diet
While a dietary intervention that benefits 70% of people with IBS seems like a home run, it does beg the question: what if you’re among the minority of people who don’t experience adequate relief from it? Where does that leave you?
There are many reasons why someone with chronic abdominal bloating, pain or bowel irregularity may not feel relief on a low FODMAP diet. But in my clinical experience, there is one that’s hands down more common than the rest: a high stool burden. As in, being backed up. Or to put it bluntly: being quite literally full of sh*t.
Yes, You Can Be Full Of Sh*t
You can be full of sh*t, or as we like to say, FOS. Because when your colon is packed full of stool—and the pockets of trapped gas that often get stuck behind that stool—you can eliminate all the FODMAPs in the world and still be a distended, bloated, painful, gassy, miserable mess. People who have historically tended toward the constipated side often aren’t surprised to hear me tell them that their lack of response to the low FODMAP diet could suggest a high stool burden.
They’ve long recognized that even low FODMAP foods that are high in fiber—like salads, popcorn, peanuts, seeds and berries—seem to feel a whole lot worse than low fiber alternatives like eggs, meat, peanut butter, bread and rice. They also recognize that the severity of their bloating improves somewhat when they are able to move their bowels well—and even more so if they are blessed with a bout of diarrhea that cleans them out more than usual. But even after a great poop, the bloating starts to build again within hours, once they resumeeating.However, I have a significant number of patients who are quite surprised to learn that they may be FOS. These are people who may move their bowels daily—sometimes even more than once. ‘How can I be constipated when I poop daily?’ they often ask me.
The answer really comes down to inputs versus outputs: how much fiber do you consume daily, and how does this compare to the amount of stool you eliminate daily? If more is going in than is coming out on a consistent basis, you can easily become backed up without even realizing it.
What Goes In Should Be Coming Out – But Doesn’t Always
It’s not abnormal for a patient who follows a whole foods/plant-heavy diet to need to move their bowels 3-4 times per day (and occasionally, even more often!) Similarly, many of my patients who follow various forms of elimination diets—whether grain free , Whole 30 or low carb—wind up eating a whole lot of vegetables and nuts to compensate for the missing food groups in their diet. These diets tend to be very high in fiber—which is objectively health-promoting, but not necessarily well-tolerated by all. Since fiber is indigestible by nature, all that goes in must come out.
Some signs that you might be FOS–even if you move your bowels daily—include:
You wake most days mildly bloated/distended, and it keeps building as the day progresses
You end every day visibly distended and often uncomfortable, in pain and/or farting a lot, no matter what you eat
Elimination diets have had only a modest impact on your symptoms
You may have the urge to move your bowels multiple times per day, but only tiny little bits come out (and sometimes, nothing comes out at all)
Even when you do go, you may feel like your bowel movements are incomplete—that there’s more in there that needs to come out but can’t
Your bloating and distension is worse after a large volume or high fiber meal, and more modest after liquid meals, small portions or low fiber meals
We Can Prove You Are FOS
If you suspect that you may be carrying around a high stool burden, a doctor can verify this with basic imaging: X-rays, ultrasounds or CT scans are all able to capture the amount of retained stool in your colon. A gastroenterologist can often tell just by looking at and palpating (pressing on) your abdomen. The question is: what to do about it once its confirmed?
If you’re lucky, resolving a case of “backed up bloating” (as I like to call it) may just require giving your bowels a bit of a nudge with some gentle over-the-counter support from osmotic laxatives like magnesium or Polyethylene glycol 3350 (MiraLAX), stimulant laxatives like senna or bisacodyl (Dulcolax), or some combination thereof.
Often, scaling back a bit on your fiber intake is helpful as well. No need to add flax AND chia to your already fibrous oatmeal with berries. Have a half soup and half salad for your plant-based lunch instead of a giant entrée salad. Get your nut fix from nut butters rather than raw, whole almonds. Eat more of your veggies cooked as opposed to raw. In my practice, I refer to this as a “GI Gentle” diet.
Let’s Talk Pelvic Floor Dysfunction (PFD)
But if you struggle to move your bowels better even with the support of an assertive bowel regimen, it may be worth considering the possibility of pelvic floor dysfunction (PFD). PFD is a term that refers to a variety of functional problems with the nerves and muscles that support the organs in your pelvic region, and that must coordinate in a specific way to enable you to move your bowels completely and easily. (I tend to think of it as ‘plumbing problem,’ as opposed to a motility problem.).
For a condition you may not ever even have heard of, PFD is surprisingly common. The best estimates I’ve seen suggest that it affects about 17% of women and 5% of men, but prevalence increases after age 40. PFD is also much higher among women who have given birth—and especially among women who have given birth vaginally. Among people who experience chronic constipation, PFD is a pretty common culprit, responsible for an estimated 30-40% of cases. In my clinical practice, I have observed that certain patients seem especially prone to being affected by PFD. These include people with histories of anorexia, emotional or sexual trauma; anxiety; “holding it in” as children (fear of moving their bowels at school or in toilets other than those in their own homes); and even those who have formal training as ballet dancers. However, I’m not aware of any research studies to have quantified whether there is indeed an increased risk among people in these groups that support my subjective observations.
PFD Is Not Just One Thing
There are different types of PFD, and they are, in turn, treated differently. One type of PFD, called dyssynergic defecation, is generally treated with a specific type of pelvic floor physical therapy coupled with biofeedback, which helps “retrain” the nerves and muscles associated with pooping so they can coordinate properly again. A pelvic floor physical therapist might also teach you different toileting positions and breathing techniques to help you evacuate more effectively.
A type of PFD in which the anal sphincter is not relaxing properly may be treated with Botox injections or rectal valium suppositories.
PFD caused by a rectocele, which is a weakening of the muscular wall separating a woman’s vagina and her rectum, can be treated in a variety of non-invasive ways—from bulking fiber supplements to physical therapy to small support devices called pessaries. Severe cases can be repaired surgically.
Given the variation in types of PFD and appropriate treatments, one can appreciate how important diagnostic testing would be in order to clarify the nature of the issue.
It’s pretty common for people with chronic bloating and other GI issues to automatically assume that their symptoms are a result of a food intolerance or sensitivity. But the relatively common occurrence of a high stool burden as a culprit for chronic bloating is an important reminder that this is not always the case.
By continuing to eliminate more and more foods in a quest to identify an elusive ‘trigger food’ that may not exist, you may find yourself on a fruitless quest for an answer you won’t find… and destroying your relationship with food and eating in the process.
If you continue to struggle with painful bloating and visible distension despite a rigorous trial of the low FODMAP diet—or other commonly recommended dietary eliminations– consider whether you might actually just be FOS. (Rest assured that you’re in excellent company if you are, and we will still love you no matter what). Once properly diagnosed, most causes of a high stool burden are treatable through some combination of fiber modification, medication, physical therapy and/or biofeedback.
Want to learn more about Fiber and IBS? Check out our article here or download this 23 page e-book for 99 cents.
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