Understanding the Low FODMAP Diet
by Dr. Megan Taylor
Low FODMAP Diet: Confused? You are not alone!
DISCLAIMER: The below is meant for educational purposes only and should not be taken as a medical recommendation to initiate a Low FODMAP Diet. Dietary modification is not appropriate for all individuals, and you should ALWAYS discuss any plans for dietary restriction, even temporary, with your healthcare provider in order to determine if this approach is safe for you.
A Low FODMAP Diet is one of the most well-studied diets in the management of Irritable Bowel Syndrome (IBS). Based on current research, 52-84% of patients report a reduction in their IBS symptoms when eliminating dietary FODMAPs (Liu, et al. 2020). FODMAP stands for Fermentable Oligosaccarides, Disaccharides, Monosaccharides, and Polyols - ie, specific types of carbohydrates that are fermentable gut microbiome. Following a Low FODMAP Diet means that you eliminate or eat a low amount of foods rich in these particular carbohydrates, as a way to reduce fermentation, and therefore reduce the types of symptoms that fermentation produces - bloating, distention, abdominal pain, flatulence, stool changes, and more.
However, unlike an anti-inflammatory diet, which eliminate relatively sensical food categories and is relatively straightforward (if not exactly easy) to follow, the Low FODMAP Diet often feels incoherent and difficult to grasp. This is because it eliminates big swaths of seemingly unrelated foods groups that have just one thing in common - their “fermentability” - which just isn’t straightforward. Some examples of FODMAP rich foods include:
Oligosaccharides (ie, fructans [FOS], galacto-oligosaccharides [GOS]): wheat, rye, onions, garlic, legumes (beans) and lentils, ripe bananas, mangos, watermelon, and others
Disaccharides (ie, lactose): milk and milk products (unless fermented/aged for at least 24 hours)
Monosaccharides (ie, fructose): honey, high fructose corn syrup, fruit juice, dried fruits, and many fruits, such as watermelon, apple, pear, and others
Polyols (ie, sorbitol, mannitol): avocado, stone fruit (ie, apricots, peaches, cherries, etc), blackberries, apple, pear, winter squash, button mushrooms, watermelon, and others
Additionally, serving size of these foods matters! For example, 1/4 of a medium sized avocado is generally considered low FODMAP, while 1/2 of the avocado would be considered moderate in its FODMAP content. When following a Low FODMAP Diet, we are not simply eliminating all of the foods that contain FODMAPs, but rather reducing their intake. This allows for a lot more dietary diversity than what might initially met the eye!
Lastly, not everyone will experience fermentation reactions to ALL FODMAP groups. So, you might have a long history of tolerating lactose-containing dairy just fine, but still do find that you struggle with other higher FODMAP food groups like beans, alliums, or brassicas. This is key for the re-introduction phase
Not particularly intuitive, right? But don’t let this overwhelm you! This diet really CAN be life changing and is worth a try for anyone suffering from IBS. Follow three simple steps when it comes to the low FODMAP Diet:
Low FODMAP Diet Phase: Lower your FODMAP intake by eliminating high FODMAP foods for 4-6 weeks, using some of the resources below
Reintroduction Phase: After following a Low FODMAP Diet, re-introduce higher FODMAP foods, one group at a time and track your symptoms to identify which groups or particular foods, you might be reacting to
Personalize your diet for the long-term: Use this phase to continue to modify and adjust your FODMAP intake to minimize symptoms in the long-term. If you are finding that you are reacting to just a small handful of foods, experiment and determine what servings sizes, if any, you can tolerate and incorporate those foods regularly.
Some tools that can make it easier:
Check out the Low FODMAP Diet App (insert link: https://www.monashfodmap.com/ibs-central/i-have-ibs/get-the-app/ ) - this app should be your “go to” source for FODMAP content in foods and a diary for re-introduction and symptom tracking
Check out the Monash University for several step-by-step guides for implementing a low FODMAP Diet and re-introduction: https://www.monashfodmap.com/3_step_fodmap_diet/
Work with a Registered Dietician who is Certified in the Low FODMAP Diet, like West Seattle’s own Michelle Babb, RD at Eat.Play.Be (hyperlink to:https://eatplaybe.com ), or has extensive experience navigating this diet
Note, the Low FODMAP Diet is NOT meant to be a long-term diet, as it is not nutritionally replete in some important key dietary nutrients (Staudacher, 2017) AND does not support a rich and diverse large bowel microbiota (So & Staudacher, 2022). If, during the reintroduction phase, you discover that you cannot tolerate big groupings of FODMAPs, this may point to an underlying condition, such as Small Intestinal Bacterial Overgrowth (SIBO), that needs to be treated. Instead of continuing to follow the extremely limited Low FODMAP Diet, instead, reach out to your healthcare provider to explore why you might be reacting to so many foods!
Looking for additional support?
Schedule a visit with one of our providers to learn more and get support!
see you in clinic,
Dr. Taylor
Resources:
Liu J, Chey WD, Haller E, Eswaran S. Low-FODMAP Diet for Irritable Bowel Syndrome: What We Know and What We Have Yet to Learn. Annu Rev Med. 2020 Jan 27;71:303-314. doi: 10.1146/annurev-med-050218-013625. PMID: 31986083.
So D, Loughman A & Staudacher HM (2022) Effects of a low FODMAP diet on the colonic microbiome in irritable bowel syndrome: a systematic review with meta-analysis. Am J Clin Nutr 116, 943–952
Staudacher HM. Nutritional, microbiological and psychosocial implications of the low FODMAP diet. J Gastroenterol Hepatol. 2017 Mar;32 Suppl 1:16-19. doi: 10.1111/jgh.13688. PMID: 28244658.