I was diagnosed with irritable bowel syndrome (IBS) in the mid 1980’s. There were no diets or solutions offered along with my diagnosis and it was really frustrating!
In 2005, scientists at Monash University in Australia studying functional gut disorders like IBS discovered a relationship between consuming fermentable carbohydrates and digestive symptoms like gas, bloating, abdominal distension and pain, diarrhea, and even constipation. They coined a word for these particular carbohydrates: FODMAPs. The term was mostly used in research until a dietitian friend and colleague of mine, Patsy Catsos, wrote and published a book in 2008 called “IBS—Free at Last” which spurred the Low FODMAP revolution in the U.S.
I first heard the term from another colleague in 2010 and quickly learned as much as possible. I’ve been teaching the Low FODMAP diet ever since! I can honestly say that the Low FODMAP Diet has improved my patients’ symptoms more than any other diet I’ve taught in my 25+ year career.
Should I try the Low FODMAP Diet?
Yes, it’s definitely worth a try, especially if you have tried simple diet solutions like removing caffeine, fatty, and fried food and reduced intake of dairy products. But I will warn you… learning the Low FODMAP diet is like learning a new language. It takes research, planning, and practicing. You will likely make lots of mistakes. In the end, the FODMAP experiment will be worth it. Even if you don’t follow the diet perfectly, it should give you key information you want to know: does what you eat affect your digestive symptoms? Even if the diet doesn’t work, that is actually good information too; it tells your medical team we need to keep looking to find a different solution.
Ready to get started? Let’s go!
The FODMAP acronym stands for:
Fermentable
Oligo-
Di-
Mono-saccharides
And
Polyols
In simple terms, FODMAPs are certain short-chain carbohydrates—sugars, starches, and fibers—which some people, especially those with IBS, cannot digest and absorb properly. All FODMAPs cause digestive distress through the same mechanisms:
- Producing gas as intestinal bacteria “eat” or rapidly ferment the carbohydrate (making gas bubbles in the process). The gas stretches the intestinal wall and triggers nerves in the gut, causing abdominal pain, bloating, and distension.
- Pulling water into the intestine by osmosis, causing urgent watery diarrhea, or for those more prone to constipation, it feels like a water balloon in your belly.
Examples of FODMAPs
There are five main categories or “subgroups” of FODMAPs; all are carbohydrates which are fermented quickly by the intestinal bacteria.
| Fermentable | Common (but not all) food sources | |
| Oligosaccharides | Fructans | wheat, onions, garlic, inulin, chicory, and fructo-oligosaccharides (FOS) |
| Galactans/Galacto-oligosaccharides (GOS) | beans, soy, and nuts | |
| Disaccharides | Lactose (milk sugar) | Milk, yogurt, ice cream, cottage cheese |
| Monosaccharides | Fructose | high-fructose corn syrup, honey, agave, mango, sugar snap peas |
| And | ||
| Polyols | Sorbitol | Blackberries, yellow peaches, avocados |
| Mannitol | Cauliflower, mushrooms, celery, sweet potato | |
| Other sugar alcohols | Sugar-free gum, candy, cookies, liquid medication, chewable medication | |
Suggestions for Starting the Low FODMAP Diet
Prior to embarking on the FODMAP journey, I recommend doing some research, reading, and preparation especially because there are a lot of nuances. The internet is full of conflicting information about which foods are high or low in FODMAPs.
Monash University has equipment that measures the quantity of FODMAPs in food. This information is entered into an app that is available for purchase. I highly recommend the Monash Low FODMAP app to help you make appropriate food choices while following the FODMAP elimination diet. For example, a yellow spotted banana would be considered high in FODMAP, while a medium-sized firm/green banana would be suitable.
I completed specialized FODMAP training and recommend meeting with a registered dietitian nutritionist that has completed a similar course. Monash University has a has a searchable dietitian registry.
Planning
On the more practical side, once you decide to begin the FODMAP elimination diet, you will need to plan what you are going to eat.
I recommend evaluating your current diet for FODMAPs and see if simple swaps can be made:
| FODMAP Subtype | Common food eaten | Use instead |
| Fructans | Garlic | Garlic-infused oil (make or buy) |
| Fructans | onion | Green/spring onion tops |
| Fructans | wheat | Slow-fermented sourdough bread (without yeast or vinegar) or gluten-free bread |
| GOS | Cashews | Small servings of walnuts or almonds |
| GOS | Black beans | Small servings of chickpeas |
| Lactose | Milk or yogurt | Lactose-free milk or yogurt; plant-based yogurt |
| Fructose | Honey | Maple Syrup |
| Fructose | Watermelon | Cantaloupe |
| Sorbitol | Blackberries | Raspberries |
| Mannitol | Button mushrooms | Oyster mushrooms |
Shopping
Going to the grocery store is daunting if you have to read all the ingredient labels! I created a handout that includes common brand name foods that are Low FODMAP. Download the handout here. You can also download a food scanner app such as Fig or Spoonful.
Steps to Getting Started on The Low FODMAP Diet:
· Watch a video on how FODMAPs work in your body
· Read a book (check your local library!)
· Download the Monash University FODMAP App
· Familiarize yourself with the common foods containing FODMAPs. Download my handout here.
· Keep 3-5 days of food records and see where common higher FODMAP foods can be swapped out for lower ones
· Plan, prepare, and shop for Low FODMAP snacks. Need ideas? Download my handout here.
· Download a food scanner app like Fig or Spoonful to help make choices at the grocery store
· Locate a dietitian (and find out if your health insurance offers coverage for outpatient nutrition counseling)
· Need recipe ideas? Use some of my favorite resources: FODMAP Everyday, A Little Bit Yummy, and Kate Scarlata
· If you are overwhelmed by preparing your own Low FODMAP food, consider using a meal delivery service such as ModifyHealth
Keywords: irritable bowel syndrome, IBS, FODMAP Diet for IBS, Low FODMAP Diet for IBS, fermentable carbohydrates, dietary solutions for IBS, diet for diarrhea
