what I learned from FODMAP elimination and reintroduction

As I mentioned recently, I’ve had IBS (Irritable Bowel Syndrome) for three years now and have struggled to get the symptoms under control. My number one issue is bloating, and although it doesn’t interfere with my life the way, say, unpredictable diarrhea would, it’s still a significant annoyance. (Diarrhea and constipation are very common IBS symptoms but not ones that trouble me.) My belly puffs up easily so my clothes need to have a bit of stretch or they don’t fit. It’s a bit of a blow to body image and it makes me not want to take photos. I’m sure part of that is vanity and subscribing to society’s notion of what is or isn’t attractive, but I also I don’t feel like I look like myself.

I did some research online and found a book that looked promising (Patsy Catsos, IBS — Free at Last!, 2nd ed. (Portland, ME: Pond Cove Press, 2012). It looks at the role that FODMAPs (fermentable oligo-, di- and monosaccharides, and polyols) may play in IBS symptoms. FODMAPs are basically fermentable simple carbs. (FYI Monash University in Melbourne is the leader in FODMAP research, so their resources are the most reliable. The Catsos book is based exclusively on Monash research but it’s getting a little out of date now.)

There are five categories of FODMAP carbs:

  • lactose, found in milk and some milk/dairy products (a simple carb [disaccharide/two sugar molecules, in this case galactose + glucose])
  • fructose, found mostly in fruit (a simple sugar [monosaccharide/one molecule])
  • fructans, wheat and onions are top sources (a simple carb [oligosaccharide/three or more fructose molecules, up to a maximum of 10)
  • galactans, legumes/pulses are a top source (a simple carb [aka galacto-oligosaccharide/three or more galactose molecules, up to a maximum of 10)
  • polyols, none of which I’d heard of other than sorbitol, but they’re naturally occurring in some fruits and vegetables like prunes, mushrooms, dates and avocados (aka “sugar alcohols” though they’re neither a sugar nor an alcohol)

In the first phase, you eliminate (the majority of) FODMAPs for two weeks with the goal of getting things settled down. It only took about a week before the bloating pretty much stopped, hooray! I don’t ordinarily weigh myself often but I’ve now gotten into a routine of weighing daily, which revealed I’d also been retaining water. I had almost resigned myself to having to buy new clothes to fit my different circumference, but it looks like that won’t be necessary now.

I’ve now done all five challenges. I found it difficult to get enough food containing the target carb in one day to give a good test and so I may retest a couple categories. That said, I observed that lactose and polyols didn’t cause a reaction, fructose and galactose caused a mild to medium reaction, and fructans caused a strong reaction. For me the usual reactions are bloating and gas, but it’s possible that the problem FODMAPs also affect my energy and mood.

(To be clear, none of these carbs are inherently “bad”. What the FODMAP testing shows is that each person’s metabolism is unique, and what results in optimum function for one person may be much less than optimum for someone else.)

My big takeaway so far is that I need to tread very cautiously with fructans. The North American diet gets about 70% of its fructans from wheat and about 25% from onions. My strategy is to start with cutting out wheat; onions will get scrapped only if necessary. And since my issue with wheat is not a gluten allergy (celiac disease), it’s not going to do me any harm if I get trace amounts of wheat in my diet from prepared foods. All the IBS does is cause inconvenience, and it’s up to me which inconvenience (bloating versus the hassle of avoiding certain common foods) I avoid and which I accept.

I’m getting a checkup next week and when I speak to the doctor I’ll ask him what testing, if any, is available here for these different categories of carbs. I’ve certainly learned something from trial and error, but I’d like more rigorous testing so I get clearer results.

This isn’t the only issue I have with carbs. I’ve also had difficulties with hypoglycemia over the years.

Food Matters

11 thoughts on “what I learned from FODMAP elimination and reintroduction

    1. This is a pretty big issue for me right now – I just finished the self-testing after 7 weeks. If discussing it helps someone else, so much the better.


  1. Promising news. I’ve been trying different floors like garbanzo just for flavor and moving more to plant based. I dont think cutting out wheat would be as troublesome as it would have been in the past.


    1. Yes, I’m encouraged this can actually be figured out now. Plant-based is good, I’m with you there.

      It’s hard to say about wheat. Certainly we have more options now from being open to other cuisine traditions, but we also rely more heavily on prepared foods, and most of them prove problematic for this issue. For me, I think low wheat is manageable primarily because I’ve gotten in the habit of keeping my carbs low for other reasons. I’m going to miss cake though.


  2. Thank you so much for this. This has made me realize even more that I should be thinking about returning to my LCHF diet, as my tummy and bowels were so much better when I did that. I just need to find the strength to do it… and every time I say that to myself, I add: I guess your tummy is not hurting enough yet… :/

    Rebel xox


    1. I’m glad you found this helpful in some way. It’s hard to make major changes to our eating habits (or any habit, for that matter). Don’t feel that you have to overhaul everything at once – just one change at a time, here and there, will add up. In fact, you don’t have to overhaul everything – if your issue is anything like mine (not allergies), you can decide what foods are worth suffering discomfort for. There’s no rule that you have to eat “perfectly”.


    1. Interesting. I haven’t reacted to small amounts of garlic and I suspect I wouldn’t react to onions if I limited myself to the same quantities as garlic. But onions and garlic are like the foundation of Western civilisation.

      I’m doing OK with excluding wheat, and maybe that’s because I didn’t eat much to begin with because of the hypoglycemia. I generally find that knowing a food will make me feel crappy makes me want it less. But then I know a place to get these really good chocolate croissants…


  3. I always feel better by limiting my wheat. I have had various food intolerances over the years and I am not certain if it is the gluten in wheat but the bloating stops when I eat less wheat products.


    1. I think on the numbers, it’s more likely to be IBS resulting from the carb in the wheat rather than the gluten (which is a protein). You might want to have a closer look at your situation because the two issues have different treatments: e.g. if gluten is the problem then you can have gluten-free wheat flour, but if the carb is to blame then gluten-free wheat flour will likely still set you off. There’s no simple test for FODMAP issues but celiac disease (re gluten) can be established or ruled out with a simple blood test.

      Liked by 1 person

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