There are many diets available for gut issues. One of the diets that has the most scientific evidence to support it is the low-FODMAP diet, or just called the FODMAP diet. The FODMAP diet identifies certain common molecules present in natural foods that can cause intestinal inflammation and pain in certain individuals – those with IBS, Crohn’s, and Ulcerative Colitis (UC) – and removes them as much as possible from the diet.
While it is important to know upfront that switching to a FODMAP diet will likely not solve ALL of you intestinal issues, it can definitely help with any pain, bloating, or inflammation you are experiencing without being too restrictive of a diet once you get used to it.
However if your intestinal inflammation is because you happen to be very sensitive to gluten, for example, or happen to have profoundly increased intestinal permeability (i.e. a “leaky gut”), then removing FODMAPs from your diet likely isn’t going to benefit you a whole lot. Getting to the root of your issues will.
Furthermore, the studies thus far show symptomatic improvement by switching to a low FODMAP diet for IBS patients, but it does not cure the issue or necessarily place patients into remission.
A meta-analysis in 2017 showed that a low FODMAP diet resulted in “…a statistically significant pain and bloating reduction compared with those receiving a traditional diet…A significant reduction in abdominal pain and bloating were described by patients receiving a low-FODMAP diet compared with those receiving a high-FODMAP diet.” (1)
There are diets out there that are similar to the FODMAP diet. One of which is the Specific Carbohydrate Diet. However, the low FODMAP diet currently has more scientific evidence to support it for symptom relief.
So What is the Low FODMAP diet?
FODMAP stands for fermentable oligosaccharide, disaccharide, monosaccharide, and polyol. It was originally hypothesized that these poorly absorbed carbohydrates and polyols that are present in natural foods get rapidly fermented by the gut bacteria, which can contribute to increased intestinal permeability. Intestinal permeability has also been shown to correlate with IBS. (3)
By removing or limiting these food components from the diet, the person will likely experience significantly less cramping, pain, and bloating. This may be because many pathogenic forms of bacteria (or even friendly forms that have just overgrown) can consume these short-chain fermentable carbohydrates, grow from them, and sometimes excrete waste products that can cause damage to or inflame the intestines.
How do You Go About Implementing The FODMAP diet?
There are usually three phases to the FODMAP diet, and how one goes about these phases depends on the philosophy of the doctor and the preferences or needs of the patient.
The three phases are:
The approach to these three phases that is most often used is the top-down approach. In this approach, you would eliminate essentially all of the FODMAPs possible in your diet [elimination]. After you have achieved good symptom relief, you would slowly add in one food at a time (I would suggest about one new food every two weeks as sometimes symptoms take a while to show up) [reintroduction]. Once you tease out which foods you can have and which you can’t, you then settle at your maintenance phase.
I would suggest still trying to introduce more foods that have FODMAPs in them over time to see if you are still reacting to them.
The other way to approach this diet is with the bottom-up approach.
Using this approach, you would only eliminate the foods highest in FODMAPs first. Then after staying here for a while, you would monitor yourself to see if you need to eliminate more or if you can start reintroducing some foods back in.
This bottom-up approach is a more “gentle” way of going through the stages of the diet, and it also helps to avoid some of the drawbacks associated with low FODMAP dieting.
Drawbacks to low FODMAP dieting
The major drawback to eating a low FODMAP diet is the potential for your gut microbiome to change in a negative way. This has been shown in the literature and is quite a common occurrence:
“Literature suggests that the changes in fecal bacterial seen from a reduced FODMAP in-take seem to mimic those seen in patients with Crohn’s disease.” (4)
This is not a good thing, because the type of bacteria that you have in your gut plays a big role in gut health and inflammation. Thus, while going on a low FODMAP diet can definitely help to reduce symptoms, the question remains: Is going on a low FODMAP diet for an extended period of time actually going to make it harder to go back to a regular diet because the gut microbiome will be in even worse shape?
In other words, is it a short-term help that could exacerbate long-term issues?
How to Mitigate This Drawback!
For most people, the safest way of going about the FODMAP diet is the bottom-up approach, as described above.
This is because the way that the low FODMAP diet messes with the gut microbiome is by reducing both short-chain carbs that feed the gut bacteria from the diet as well as the polyphenols that are naturally present in those whole foods (the polyphenols can positively modulate the gut microbiome). (5)
The other way that you can help to either mitigate or completely nullify the negative changes on the microbiome is by choosing better foods to eat while still eating low FODMAP.
As stated above, fermentable carbs (i.e. pre-biotics) and polyphenols/phytonutrients (for example, the flavonoids in blueberries that make them “blue”) help to positively modulate the gut microbiome quite significantly. (6) Having as much of these as possible while still removing high FODMAP foods will help reduce digestive discomfort while still allowing the beneficial bacteria to be fed with pre-biotics and will inhibit the growth of the pathogenic bacteria with the polyphenols.
So consider the following two meals, both of which are low in FODMAPs, and try to think about which would be better for the health of your microbiome:
Meal 1: A few eggs with cheddar cheese on it with gluten-free white toast with butter on it on the side.
Meal 2: A few eggs with cheddar cheese with some clementines and grapes on the side.
Hopefully, you can see that meal 1 is almost completely devoid of polyphenols, whereas the oranges and the grapes provide the much-needed polyphenols/phytonutrients necessary to keep the gut healthy while on this restrictive diet.
Furthermore, trying to incorporate foods that are low in FODMAPS but high in fiber will give the bacteria in your gut some food to stay healthy. Combining this pre-biotic fiber with fruits and vegetables high in polyphenols will furthermore make it even more likely that the beneficial bacteria will thrive and the pathogenic bacteria will be controlled. So try incorporating foods like whole oats, quinoa, brown rice, broccoli, and other foods high in fiber.
So What Foods to Eat on a Low FODMAP Diet?
Here is a very nice list to start with taken from ibsdiets.org: click here to download the PDF
Try to study that list and get a good idea of what is high in FODMAPs and low in them. Remember, this isn’t a lifelong commitment, but it could help you figure out which foods may be bothering you most.
Remember to include a variety of fruits and vegetables. Both are high in polyphenols and help to make this diet work better in the long term. For example, organic spinach not only has an abundance of polyphenols but is also high in fiber and micronutrients!
How to Start?
With a top-down approach, you would just simply try to eat nothing on the “High FODMAP” list and only eat from the “Low FODMAP” list. Eventually, you will be adding foods higher in FODMAPs back in your diet during the “reintroduction” phase as detailed above.
With a bottom-up approach, which may be safer for most people who are not in an emergency situation with their IBS symptoms, you would start out by only eliminating the foods highest in FODMAPs first. See how you feel after just eliminating the most aggravating foods before you start taking away even more food from your diet.
The foods highest in FODMAPs include (based on how much we typically consume, not based on the amount per ounce):
- Wheat, amaranth, barley, and rye
- Garlic and onions
- High FODMAP fruits and vegetables (from the list above)
- Legumes and lentils
- Sweeteners high in fructose (again, see the list above)
- High FODMAP diary (from the list above)
If you want to start the low FODMAP diet with the bottom-up approach, slowly cut out a few foods, but not too many, and monitor how you feel for a couple of weeks. If you notice some improvement but want more, then try cutting out some more high FODMAP foods until you get to a comfortable place.
One good app to use to help you with this process is the Monash FODMAP app. It takes into account not only the type of food you are eating but also the amount. For example, 2 slices of wheat bread might be too many FODMAPs for you, but 1/2 of a slice might sit well with you. It is a good app to get you started.
While limiting your intake of high FODMAP foods will not cure your IBS or gut issues and it isn’t the only solution by far, it can be a very useful tool in your toolbox. Just remember about the drawbacks of removing high FODMAP foods, and try to incorporate as many polyphenols and as much fiber as you can within the confines of the diet.
Go ahead and leave a comment, question, or any experience you have had regarding the low FODMAP diet!
- Altobelli E, Del negro V, Angeletti PM, Latella G. Low-FODMAP Diet Improves Irritable Bowel Syndrome Symptoms: A Meta-Analysis. Nutrients. 2017;9(9)
- Donnellan CF, Yann LH, Lal S. Nutritional management of Crohn’s disease. Therap Adv Gastroenterol. 2013;6(3):231-42.
- Zhou Q, Zhang B, Verne GN. Intestinal membrane permeability and hypersensitivity in the irritable bowel syndrome. Pain. 2009;146(1-2):41-6.
- Halmos EP. A low FODMAP diet in patients with Crohn’s disease. J Gastroenterol Hepatol. 2016;31 Suppl 1:14-5.
- Klinder A, Shen Q, Heppel S, Lovegrove JA, Rowland I, Tuohy KM. Impact of increasing fruit and vegetables and flavonoid intake on the human gut microbiota. Food Funct. 2016;7(4):1788-96.
- Y. Desjardins; BLUEBERRIES AND FRUIT POLYPHENOLS MODULATE THE GUT MICROBIOME AND MAY PREVENT AGE-RELATED DYSBIOSIS , Innovation in Aging, Volume 1, Issue suppl_1, 1 July 2017, Pages 1363, https://doi.org/10.1093/geroni/igx004.5011