woman in a yellow hoodie holding her stomach in pain due to IBS

What Is IBS?

Irritable bowel syndrome (IBS) is a familiar term that may not be fully understood by many. It is not a disease but is considered a functional disorder depending on symptom presentation. The American College of Gastroenterology has created criteria for diagnosis which includes recurrent abdominal pain (at least one day per week) accompanied by changes in stooling patterns (either frequency or form/appearance of stool). Bloating is often a common symptom but this is not required for a formal diagnosis. It is hard to estimate the prevalence of IBS due to the likelihood of being under-diagnosed, but some estimates are as high as 17 percent of the population. Women are two times more likely to present with symptoms than men.

There are three main subtypes:


Indicating more loose stool or diarrhea, is classified by having more than 25% of your bowel movements being loose or watery and less than 25% of your bowel movements being classified as hard or lumpy.


Indicating more hard stool, is classified by the opposite presentation. More than 25% of your bowel movements are hard or lumpy and less than 25% of your bowel movements are loose or watery.


Indicates a “mixed” or “alternating” form of IBS. This subtype is classified by having both hard/lumpy stools and loose/watery stools.

How To Treat IBS

The American College of Gastroenterology has provided updated clinical guidelines for treating IBS with a range of recommendations that vary based on strength of evidence and supporting research1. It is important to note that the first step in understanding if you have IBS is to work with a gastroenterologist first. If you have an IBS diagnosis and are not experiencing relief, working with a registered dietitian can help identify an individual eating and nutrition plan that can help with symptom management.

Rule out potential problematic concerns or diagnoses that can present with similar symptoms- this requires a visit to a gastroenterologist

Unfortunately, GI symptoms alone may not be enough to rule out other diagnoses like celiac disease, inflammatory bowel disease, or even cancer. Each can present with similar symptoms and require additional testing. Red flag symptoms that should be investigated right away include: blood in the stool, anemia, unintentional weight loss, consistent bowel movements throughout the night, fever, or worsening symptoms that are not going away. If you are above the age of 50 and have sudden, abnormal bowel movements, that can also be a red flag to reach out to your doctor about. 

Do NOT do an elimination diet on your own- this requires guidance and support from a registered dietitian

Some doctors, or more recently, social media influencers, may recommend cutting out certain food groups or following a low fodmap diet without any formal instruction and guidance. Long-term elimination without reintroduction adds risk for deficiency and negative influence on quality of life. A proper elimination diet takes time and expert oversight followed by specific reintroduction over a few weeks and everyone’s reintroduction phase will look different. As tempting as it may be to do this on your own, consider gaining additional support to help you find the best nutrition intervention for you!

Complete a symptom log and food diary

Collect the data. This will be something your registered dietitian will likely ask of you to help you have an individual plan. The more data you have the easier (and quicker) it will be to find if there are any food triggers influencing your symptoms.


Consider the gut-brain connection

Research is investigating the link between emotional and mental well-being and the gut. We can thank our vagus nerve for stomach butterflies and many GI symptoms similar to IBS. In fact, some research is even supportive of utilizing interventions like CBT or hypnotherapy for managing IBS symptoms. IBS has more recently been deemed a “disorder of gut-brain interaction” that can be further influenced by biology and lifestyle. If you find that your GI symptoms have increased alongside some seasons of high stress, anxiety, life change, or changes in mental health, this could be something to investigate and find helpful support for.


If you are still not finding relief, your dietitian may recommend going back to your medical provider and asking about ruling out other etiologies that can be mis-diagnosed as IBS.

These include:

    1. SIBO- small intestinal bacterial overgrowth
    2. Bile acid diarrhea
    3. Pelvic floor dysfunction
    4. Nickel allergy
    5. Histamine intolerance
    6. Congenital Sucrase Isomaltose Deficiency
woman holding her stomach in pain from IBS

Our team of registered dietitians can help you feel more equipped with understanding how nutrition may be impacting your IBS. If you feel like you need extra support and guidance, reach out to our scheduling team today!

Kelly Myers

Kelly Myers


Kelly is a Licensed and Registered Dietitian Nutritionist with a passion for helping individuals and families. She completed her Bachelor’s Degree in Food Science and Human Nutrition from the University of Florida before moving to Saint Louis to complete her Dietetic Internship and Master’s degree in Nutrition and Dietetics at Saint Louis University.



  1. Lacy BE, Pimentel M, Brenner DM, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021;116(1):17-44. doi:10.14309/ajg.0000000000001036
  2. Camilleri M. Diagnosis and Treatment of Irritable Bowel Syndrome: A Review. JAMA. 2021;325(9):865–877. doi:10.1001/jama.2020.22532
  3. Black CJ, Thakur ER, Houghton LA, Quigley EMM, Moayyedi P, Ford AC. Efficacy of psychological therapies for irritable bowel syndrome: systematic review and network meta-analysis. Gut. 2020;69(8):1441-1451. doi:10.1136/gutjnl-2020-321191