The Low-FODMAP Diet: Closest Thing to an IBS Diet?

13 min read



It seems like the only advice we ever get to improve our health is “diet and exercise”, even though we often need a lot more than what lifestyle modifications can provide. But could this be one of those times when diet is just what you need? Of all the diets and tricks out there, the low-FODMAP diet has genuine promise to help you manage your irritable bowel syndrome (IBS) symptoms.


As the saying from Hippocrates goes, all disease begins in the gut. But what he didn’t say is that the little microorganisms in our intestines that make up our microbiome are a large part of this disease puzzle—and a large part of why diet really does make a difference when it comes to IBS.


Gut Bacteria Like to Eat Too


Just like us, all the microorganisms that live in our gut need to eat to survive; essentially, what we eat, they eat. But not all bacteria desire the same foods. Some prefer carbohydrate-rich diets while others like specific forms of fiber or certain types of fat. As a result of all these differences, the bacteria that make up our gut microbiome can be affected by different types of food, which can have a dramatic impact on our health. This, of course, extends to people with IBS.


In today’s world where we’re constantly bombarded with different types of diets, it can be quite intimidating when it comes to figuring out what works best for ourselves. Unfortunately, the truth is not nearly as clear and exciting as we would like it to be. The reality is that understanding the interactions between our diet, microbiome, and conditions such as irritable bowel syndrome, inflammatory bowel diseases, or any intestinal pain or discomfort, is extremely complicated.


While there is some debate around the causes of IBS and its subtypes, the disorder is characterized by abnormal interactions between the gut and the brain. Therefore, IBS is linked with mental health issues as well as intestinal imbalances, whether it be an altered microbiome or the gut itself malfunctioning. Some studies even suggest that up to 63% of IBS related symptoms are triggered by dietary choices, so it’s logical for people to be worried about how their food consumption can hurt them rather than help them 1.


In fact, a lot of the symptoms of IBS are brought on as a result of the worrying and anxiety individuals feel due to the risk of feeling pain and discomfort after certain meals or activities 2. .Therefore, having a strong handle on what foods to avoid, and which to eat more of, can have a dual effect by also providing peace of mind. The less you have to worry about a symptom flare-up, the better off you’ll be! Diet certainly has a lot to do with this.


There is no comprehensive treatment or cure for IBS, so regulating your gut microbiome through the foods you eat is a solid place to start. As a result, it is common for people to try to initially restrict certain dietary elements such as lactose, gluten and fructose—things that are often found in items such as spicy dishes, fatty foods, alcohol and dairy products. Then there’s the diets that have been developed to limit specific dietary components for those with IBS. That’s where the low-FODMAP diet comes in.


The Low-FODMAP Diet


One of the most difficult things about dealing with IBS is knowing what to eat and what not to eat. If you have irritable bowel syndrome, you’ve probably experienced the frustration that can come from eating food. Perhaps something you may have enjoyed without much thought in the past becoming something of a land mine...Even if you have a handle on your food intake and IBS symptoms, slip ups happen, and problem ingredients can even be hidden in foods unexpectedly. This type of guessing game or accidental consumption of trigger foods can impact your intestinal peace of mind and trigger anxiety related to your IBS.


Given this challenge, it makes sense that people who live with IBS end up experimenting with different diets. There may not be a one-size-fits-all IBS diet, but many people experience positive results on a low-FODMAP diet. FODMAP stands for Fermentable Oligo-, Di-, Mono-saccharides and Polyols.


To put it simply, FODMAPs are a specific class of small indigestible carbohydrates. This means that instead of being digested normally, which allows for nutrients to be broken down and transported throughout the body, these carbs instead stay inside our intestines where they can then be consumed by our gut bacteria 3. The potential problem with this is that these bacteria are major producers of gases such as hydrogen, so when they eat foods rich in FODMAPs, there can be some issues. The release of gases made by these bacteria can lead to increased intestinal pressure and discomfort in the form of cramps, bloating, or flatulence and also cause changes in bowel habits 4.


Eating less FODMAPs not only combats this, but also helps regulate transit time (how long it takes for food to travel through the digestive tract), and gut motility (how well your gut muscles move food through the digestive tract), by preventing the gut from encountering foods it might be sensitive to 4.


Luckily, for people who don’t have IBS, FODMAPs don’t tend to cause many problems. However, because those with IBS have a very sensitive gut, the excess water and gas released from the digestion of FODMAPs can result in the frustrating symptoms of IBS. Furthermore, gut bacteria known to produce high amounts of gas have been found to be more abundant in IBS patients, making the digestive symptoms even more severe 5. Therefore, it is the combination of IBS patients having more problematic bacteria such as Bifidobacteria and difficulty digesting FODMAPs that makes reducing FODMAP consumption important for people with IBS 4.


FODMAPs are found in different types of food that are often everyday staples for many: onions, apples, soy milk, honey and cashews being a few examples. In general, all FODMAPs can theoretically trigger IBS symptoms, but not necessarily all of them will: each person’s gut microbiome is different, and so are their reactions to different FODMAP foods 4. For a more complete list, check out Monash University’s “3 step FODMAP Diet guide”.


Following a low-FODMAP diet requires just about as much forethought as one might expect.

Since many FODMAP items are common and in generally healthy food options, those looking to experiment with and try out the low-FODMAP diet should consult a registered professional such as a physician or dietitian to make sure that food restrictions are appropriate and done responsibly. This will also help to maintain a healthy daily consumption of key nutrients.


Although this is significantly more drastic than the usual no chocolate or no bread diets we’re accustomed to hearing about, the low-FODMAP diet, when pursued correctly, has the potential to greatly reduce intestinal pain and discomfort for those who need it most. For this reason, it is frequently suggested that people on the diet eliminate all FODMAPs for 4-8 weeks (called a “global restriction”), then begin to slowly reintroduce certain foods back into their diet, allowing people to observe which foods result in digestive issues. This helps the individual better gauge their tolerance to different foods and create a personalized plan that uniquely caters to their specific needs; while at the same time ensuring that their personalized food regimen provides enough nutritional value 4.


At this point, you might already be making plans to cut the apple pie, lose the onion breath, and say bye bye to FODMAPs. But not so fast…


This is a good time to ask, should you follow this diet?


While the restrictive nature of the low-FODMAP diet may convince you it’s a cure-all, this is sadly not the case. Just as is the reality with all health interventions, they don’t work for everyone. Monash University, whose researchers developed the low-FODMAP diet in the first place, have reported that 75% of people in their study who avoided FODMAPs experienced relief from their IBS symptoms. They also reported that participants who found the diet effective had less bloating, pain, constipation, and diarrhea within 2-6 weeks. So it's no wonder the low-FODMAP has been heralded as the IBS diet! But don’t forget: it’s crucial that you seek support from health professionals to ensure that you can try this diet safely and maintain it properly. Having a strong understanding of your illness and knowing your body will help you get the best guidance.


However, due to the complexity of approaches such as the low-FODMAP diet, they commonly lack substantial evidence for their long-term benefit, even though short-term relief from symptoms is commonly seen. Future studies will certainly be needed to understand the relationship between our diet and our microbiota, including a deeper understanding of how our gut microbiome changes over time in relation to the symptoms patients experience. This is especially important in the case of IBS patients where symptoms are known to vary over time even for a single individual, which can explain why the formula for how to treat IBS remains so elusive.


Now, if you’re going to put all that work into changing your diet, you’re probably going to want to know if it’s working. With Phyla’s comprehensive gut health solution, you can track how a low-FODMAP diet is affecting your gut health, from your microbiome to your quality of sleep and daily symptoms. Start tracking your meals and symptoms on our free app and sign up for our new microbiome testing service to see how, over time, your diet and lifestyle is affecting your gut health. With personalized dietary recommendations, you’ll even be able to pinpoint exactly which foods to eat more of and which to avoid, which helps take out some guesswork.


Download our app today on iOS or Android!


For more information on a low FODMAP diet, read Monash University’s article, “FODMAPs and Irritable Bowel Syndrome”. Monash University did the original research to come up with the concept of FODMAPs.


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1 https://www.ncbi.nlm.nih.gov/pubmed/11244249

2 https://onlinelibrary.wiley.com/doi/10.1111/nmo.13828

3 https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works

4 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019579/

5 https://www.ncbi.nlm.nih.gov/pubmed/21820992