A patient’s guide to the FODMAP diet.

As with many things I write about as a Gastroenterology fellow, my topics come from my friends and family. Recently, at my parent’s dinner party, the topic of the FODMAP diet was thrown around. Many of my mother’s friends were curious about this “diet.”

I would like to start out by saying calling the FODMAP plan a diet is a misnomer. The FODMAP diet is NOT for losing weight. Instead, its purpose is to identify triggers for abdominal symptoms. FODMAPs or Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols are a collection of carbohydrates found in food that can be poorly absorbed by some people.


Fermentable Gut bacteria ferment undigested carbohydrates to produce gas
Oligosaccharides Fructans found in foods such as wheat, rye, onions, garlic and legumes/pulses.
Disaccharides Lactose found in dairy products like milk, soft cheeses, and yogurt
Monosaccharides Fructose found in honey, apples, high fructose corn syrups
Polyols Sorbitol and Mannitol found in some fruit (peaches, cherries) and vegetables (cauliflower, snow peas).

It’s also used in artificial sweeteners (sorbitol)

This poor absorption leads to chronic, relapsing symptoms including lower abdominal pain or discomfort, bloating, flatulence, distention, and altered bowel habits (ranging from diarrhea to constipation). The main reasons that symptoms arise is twofold. Firstly, FODMAPs pull extra water into your digestive tract causing bloating and diarrhea. Secondly, bacteria in the intestine fermet FODMAPs and produce gas. This extra water and gas leads to cramping and abdominal pain.

If you’re having these symptoms, talk your doctor. Armed with your history and a negative workup with no abnormal pathology, your physician may diagnose you with Irritable bowel disease (IBS). It’s actually a pretty common diagnosis. In the United States, it is estimated that 10-15% of patients suffer from IBS. Once you have this diagnosis, your physician will recommend the FODMAP dietary regimen.  

The “diet” begins with a 2-6 week period of restriction of all FODMAPs. When you start to avoid certain fodmaps remember to read the ingredients in food products very closely to be thorough. The next difficulty is knowing what FODMAPs are in each type of food: For example, if you wanted to eat an apple, knowing that it has fructose and polyols is important. Here is a list of foods that are high in FODMAPs. It might be overwhelming seeing all of these restrictions. Here is a list of foods that are low in FODMAPS. Real sensitivity to a certain FODMAP will mean quick improvement in symptoms with cessation.

Then slowly reintroduce these FODMAPS one at a time. Continue to avoid the remaining FODMAPs to really isolate your triggers. Start with a normal amount of food and then titrate up to determine how much of this trigger can cause symptoms. For example, you are reintroducing yogurt. You should start at half a serving and titrate up to one serving to determine at what quantity triggers symptoms. Don’t forget to track your food and your symptoms. If you want a sample tracking sheet, you can print the PDF in the link below.

Personally I love this website for a thorough explanation of the FODMAP diet and free resources including a sample tracking sheet (Here).

If you have tried the FODMAP dietary regimen, let me know your experiences!



3 thoughts on “A patient’s guide to the FODMAP diet.

Add yours

  1. Hi KEERTHI, this is kalpesh uncle from Ahmedabad.first nice to read about your FODMAT diet.very interesting and useful to know more about .keep posting all your finding on this article.


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