The low FODMAP diet (LFD) is a popular diet among people with gut health issues, especially those with irritable bowel syndrome (IBS). It’s a highly effective diet in the right circumstances, but not everyone will reap its benefits. If you find yourself wondering, why is the low FODMAP diet not working for me?’, then check out the potential reasons below.
You don’t actually have IBS
It can he incredibly tempting to do a quick Google search of your symptoms, identify your problem, and move on to interventions so you can feel better fast. But while Dr. Google is easy, free and super helpful, it’s not always right. Any doctor will tell you that diagnosis is far more nuanced than simply comparing a list of symptoms to a list of criteria.
If you decide you have IBS without consulting a physician, it’s quite possible that you got it wrong and don’t actually have IBS. As a result, you may waste a lot of time and money chasing diets, supplements and other strategies that don’t work. It also means you’ll suffer far longer than you should before you feel better.
So go talk to your doc about your symptoms.
One of the challenges of diagnosing IBS is that the symptoms overlap with other gut conditions, like celiac disease, inflammatory bowel disease, and colon cancer. Some non-gut conditions share symptoms with IBS too, like ovarian cancer and endometriosis. Even simple lactose intolerance can be mistakenly labelled as IBS if you’re not thoroughly assessed.
If your family physician diagnoses IBS and evidence-based interventions don’t help (eg. low FODMAP diet, fibre therapy, cognitive behavioural therapy, gut-directed hypnotherapy, etc), consider asking your family doctor for a referral to a gastroenterologist (a doctor who specializes in gut health) in case there’s something more to your symptoms.
Flawed resources
Online lists of low and high FODMAP foods are notoriously incorrect, usually because they’re out of date. This means that you may not be following the low FODMAP diet accurately enough to see changes in your symptoms.
FODMAP content in foods can change over time depending on where the plant grew, climate influences, plant varieties farmers use, and seed modifications to make the plants more resistant to pests and disease.
Researchers at Monash University, where the low FODMAP diet originated, are constantly testing new foods for FODMAP content and re-testing old ones. This makes the Monash FODMAP app the most comprehensive and up to date resource.
Another problem with these lists is that they don’t usually include all the foods that have been tested, so you could end up with a pretty limited list of “allowed” foods.
My pet peeve with these food lists is that they take a black and white approach to the diet by telling readers to “eat this, not that”, when in actuality you CAN enjoy high FODMAP foods in low FODMAP serving sizes.
To ensure you’re following the low FODMAP diet as accurately as possible, use the Monash University FODMAP app instead of any online lists or dated handouts.
High expectations
The low FODMAP diet can improve symptoms in 50-87% of people with IBS, so although most people will feel better on the diet, not everyone will benefit. Similarly, research finds that the LFD improves symptoms rather than eliminates them.
It’s important that you’re aware of this because your attitude and expectations going into the diet will shape your assessment of whether or not it worked for you.
If you think it will eliminate symptoms but instead you find your abdominal pain rating goes from 8/10 to 5/10, you might think it failed, when in actuality it reduced your pain. Ultimately, you need to decide if a pain rating of 5/10 represents adequate symptom improvement for you.
Another important thing to note is that the LFD improves abdominal pain, gas, bloating and diarrhea, but it seldom improves constipation. So folks with IBS-C may be sorely disappointed if the expectation is that the LFD will relieve constipation.
Restaurant food
People who eat out often will struggle to reduce their FODMAP intake adequately to feel the effects of the diet.
One reason for this is that garlic and onion seem to be in everything, and they’re pretty common symptom triggers. They’re difficult to remove from foods because they’re often part of the foundational sauce, spread, rub, etc that makes the meal so delicious. This makes fructans (the FODMAP group to which garlic and onion belong) difficult to reduce sufficiently for a successful elimination phase.
You don’t have to stop eating out altogether when following the low FODMAP diet, you just need to have a plan. Check out my post “Eating Out Low FODMAP” for tips and restaurant ideas.
You’re (unknowingly) already following a low FODMAP diet
People with IBS tend to cut out a wide range of foods in an effort to calm unruly digestive symptoms. Since gluten-free and dairy-free diets are common among IBS sufferers, it’s not too difficult to unknowingly end up on a lower FODMAP diet.
When it comes time to further cut back on FODMAPs during the elimination phase of the diet, symptoms may not improve drastically. This will probably leave you feeling like the diet didn’t work.
A Monash FODMAP trained dietitian can assess the FODMAPs (amounts and types) in your current diet and advise you on how to move forward.
Mental health may be the primary trigger
IBS is a disorder of gut-brain interaction. Basically, this means that the bi-directional communication between the brain and the gut isn’t functioning optimally. As a result, sensations in the gut are heightened and your brain interprets this as pain.
For some IBS sufferers, food actually takes a backseat to negative emotional states like depression, anxiety and stress when it comes to gut symptoms. If you overlook the importance of your mental health in symptom generation, the LFD may not be terribly effective for you.
One way to combat this is by prioritizing your mental health via evidence-based interventions like cognitive behavioural therapy and gut directed hypnotherapy. Once you’re feeling more stable you can try the low FODMAP diet if any lingering symptoms continue to plague you.
Other lifestyle factors
Other lifestyle factors can also affect GI symptoms. One such factor is eating at irregular times or not eating much throughout the day and then overloading your gut with a big meal and evening snacks before bed.
A diet high in processed foods can influence symptoms too since processed foods tend to be high in fat and sugar and low in fibre. Poor sleep, a sedentary lifestyle, and high alcohol intake may also contribute.
If any of these factors play a significant role in your symptoms and you attempt the low FODMAP diet, you may not see great outcomes and falsely attribute that to the diet.
It’s best to improve diet quality and lifestyle first before embarking on the low FODMAP diet for two reasons:
- Lifestyle changes might improve gut symptoms enough that you won’t feel the need to do the LFD.
- You’ll have a more accurate gauge of how your body responds to the LFD if other factors aren’t muddying the waters and influencing symptoms.
If you tried the low FODMAP diet and it didn’t work for you, is it possible any of the above factors played a role?
xoAndrea, RD
