One of the biggest misconceptions about IBS is that FODMAPs are the only thing that trigger symptoms. While the low FODMAP diet can be incredibly helpful for many people, it’s not the full picture.
In fact, there are several non-FODMAP triggers that can aggravate IBS symptoms, even when your meals are technically “low FODMAP.”
Here are some common reasons your low FODMAP diet might not be working as well as you hoped.
1. Coffee
A lot of people are surprised to learn that coffee is considered low FODMAP, however “low FODMAP” doesn’t automatically mean “gut friendly.” Coffee, including decaf, can stimulate the digestive tract and speed up bowel movements. For some people with IBS, this can lead to:
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Urgency
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Diarrhoea
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Cramping
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Stomach discomfort
If you notice your symptoms flare after your morning coffee, it may not be the milk or sweetener causing the issue, it could be the coffee itself.
This doesn’t necessarily mean you need to give it up forever, but it may be worth experimenting with:
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Smaller serves
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Drinking it with food
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Switching to lower-caffeine options
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Reducing frequency
2. Fat Content
You can eat a completely low FODMAP meal and still feel bloated, heavy, or uncomfortable afterwards if the meal is very high in fat.
Fat naturally slows stomach emptying, which can leave you feeling overly full or nauseous. Then once it moves into the intestines, it can stimulate the gut quite strongly, something that people with IBS tend to be more sensitive to.
Common high-fat foods that may aggravate symptoms include:
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Large takeaway meals
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Fried foods
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Creamy sauces
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Very rich desserts
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Large amounts of oils or butter
This doesn’t mean fat is “bad” or that you need a low-fat diet. It’s usually more about the portion size and overall load in one sitting.
3. Alcohol
Many alcoholic drinks can be low FODMAP in certain serves, but alcohol itself can still irritate the gut. Alcohol may affect:
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Gut motility
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Intestinal permeability
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Digestion and absorption
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Gut sensitivity
This can trigger symptoms like:
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Diarrhoea
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Bloating
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Reflux
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Abdominal pain
For some people, it’s not noticeable until they’re already in an IBS flare. For others, even small amounts can be enough to trigger symptoms. If you feel like you’re “doing everything right” with FODMAPs but still struggling, alcohol is one of the biggest non-food things worth considering.
4. Fizzy Drinks/Carbonated Beverages
If bloating and pressure are major symptoms for you, carbonated drinks may be contributing more than you realise. The gas in fizzy beverages can cause extra stretching and distension in the digestive tract. People with IBS often have a more sensitive gut-brain response, even normal amounts of gas can feel painful or excessive.
This includes:
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Soft drinks
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Sparkling water
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Kombucha
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Energy drinks
Sometimes it’s not the ingredients in the drink causing symptoms, it’s simply the carbonation itself.
5. Spicy Food
Spicy foods are another example of something that can be low FODMAP but still trigger IBS symptoms. The compound responsible for the “heat” in chilli, called capsaicin, can irritate the digestive tract and worsen symptoms like:
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Abdominal pain
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Burning sensations
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Diarrhoea
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Urgency
This doesn’t mean everyone with IBS needs to avoid spice completely. Many people tolerate mild spice well, especially in smaller amounts or when balanced through a meal.
IBS is about more than just FODMAPs
The low FODMAP diet can be an incredibly useful tool, but it’s not meant to be viewed as the only answer to IBS. If your symptoms aren’t improving, it doesn’t necessarily mean:
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You’re “doing the diet wrong”
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You need to restrict more foods
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Your IBS is untreatable
Sometimes the missing piece is looking beyond FODMAPs and considering other gut triggers, eating habits, stress, meal size, exercise, sleep, and nervous system factors too.
IBS is a frustrating and forever changing condition to manage. The best way to know if something triggers your symptoms is by eliminating it one thing at a time, if you change too many things at once, you won’t know what has and hasn’t worked.