If you are wondering “What is the Low FODMAP Diet?” or looking to learn more about FODMAPs, this page is a great place to start. This guide was written by an IBS-specialist dietitian and is updated regularly.
Essentials of the Low FODMAP Diet
The low FODMAP diet is an elimination diet designed to help decrease the digestive symptoms experienced by people with IBS. Unfortunately, it is not a cure for IBS. Research has found that approximately 3 out of 4 people with IBS have their symptoms improved on this diet.
The diet has three phases, and it is essential to complete each phase. It is important to note that it is NOT a weight loss diet. It is also not the only option for IBS symptom management. This article summarizes the key points of the low FODMAP diet.
NOTE: This diet was made to be completed with the help of a Registered Dietitian. Always talk to your doctor and/or dietitian before making dietary changes.
What are FODMAPs?
FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols) are a group of carbohydrates found in food that are highly fermentable. The fermentation of FODMAPs by bacteria in the bowel (also known as the production of gas) is a normal and healthy part of digestion. For people with IBS however, eating foods high in FODMAPs may trigger symptoms such as excess gas, bloating, distension, cramping, constipation and/or diarrhea.
Some foods contain no FODMAPs, some foods contain only one type of FODMAP, and some foods contain multiple types of FODMAPs. Reducing the amount of high FODMAP foods in your diet may help improve IBS symptoms. Every person is unique, and every person with IBS has a different reaction to each type of FODMAP.
Types of FODMAPs
There are 5 types of FODMAPs:
- Lactose – found primarily in dairy products (e.g., milk, yogurt, etc.)
- Fructose – found primarily in certain fruits, vegetables, and sweeteners (e.g., mango, asparagus, honey, agave, etc.)
- Fructans – found primarily in certain fruits, vegetables and grains (e.g., garlic, onion, wheat, etc.)
- Galacto-Oligosaccharides (GOS) – found primarily in certain legumes and nuts (e.g., kidney beans, pistachios, cashews, etc.)
- Polyols – found primarily in certain fruits and vegetables, and used as a sweetener in certain processed foods (e.g., peaches, cauliflower, sugar-free gum)
For the most part, you cannot easily guess which foods contain FODMAPs. FODMAP content of foods is determined in food testing labs. Monash University releases the results of their tests through their App.
FODMAPs vs Gluten
The low FODMAP diet is not a gluten-free diet. Gluten is not a FODMAP. Irritable Bowel Syndrome is very different than Celiac disease. Here is a post all about gluten and the low FODMAP diet.
Wheat, barley and rye are limited on the low FODMAP diet due to their fructan content. Small portions of some wheat products are low FODMAP and okay for those with IBS. However, if you have Celiac disease, it is essential to avoid all gluten, including trace amounts. The Canadian Celiac Association has more information about celiac disease.
What is an Elimination Diet?
An elimination diet is where you remove all foods from your diet which may be causing symptoms for some time, and then try challenging the FODMAP groups (i.e., eating high FODMAP foods) one at a time. This is how we find out which high FODMAP foods you react to and how much you can tolerate. The low FODMAP elimination diet has three phases.
- Phase 1 – Low FODMAP: Only eat foods that contain little or no FODMAPS for approximately 2 – 6 weeks (or until symptoms are well managed).
- Phase 2 – Reintroduction/Re-challenge: After 2 – 6 weeks, and improvement in symptoms, FODMAP groups are systematically tested one by one and symptoms are recorded. This phase will take approximately 8 weeks. A personalized schedule for reintroduction should be made with your dietitian.
- Phase 3 – Personalization/Modified Diet: After challenging each FODMAP group, a list of “safe” foods (i.e., foods you can eat without symptoms) and a list of “trigger” foods (i.e., foods which give you symptoms at certain serving sizes) are created. A variety of “safe” foods are now consumed. There may be some “trigger” foods you are fine with in small quantities.
The Reintroduction phase is the most important phase of the diet. It is likely that not all 5 FODMAPs will cause you significant symptoms. The only way to find out how much of each FODMAP you can eat without experiencing symptoms is to systematically test them. Most individuals can reintroduce some FODMAPs back into their diet while maintaining symptom control.
What foods are low FODMAP?
During the diet it is important for you to eat only low FODMAP portion sizes of foods. Avoid the high FODMAP foods. The Monash App has every food that has been tested for FODMAPs and I HIGHLY recommend downloading it.
I’ve created a simple low FODMAP grocery list with the most common foods in Western countries. Even with the lists, I still recommend getting the app.
The first page of the grocery list summarizes low FODMAP foods that are safe for the diet. It’s great for using as a reference or low FODMAP shopping list while at the store. PThe second page summarizes the most common high FODMAP foods to avoid on the diet.
Nutrients and the Low FODMAP Diet
It may be a lot of work, but it is important to still eat a variety of foods while on the low FODMAP diet. Eating a variety of foods helps us get enough of the all the nutrients we need! Two nutrients of concern are calcium and fibre.
Try to eat a variety of calcium-containing foods (e.g., hard cheeses, lactose-free milk, lactose-free yogurt, fortified milk alternatives, firm tofu, etc.). You should aim to meet the fibre requirements each day (25 g for women, 38 g for men), especially if constipation is one of your symptoms. Fruit, vegetables, whole grains, nuts and seeds are great sources of fibre. Keep hydrated by sipping on water throughout the day and also when eating high fibre foods.
Here is a sample healthy day of low FODMAP foods for the first phase. Here is a sample vegetarian low FODMAP day.
What Next?
The low FODMAP diet will require a lot of effort, but it can have a significant positive impact on your symptoms. You may see improvement in your symptoms in the first week of the diet, or it may take a few weeks to see an improvement.
In the end you should be able to manage symptoms and have a healthy varied diet! Remember, reintroducing FODMAPs is the most important part of the diet.
There are other options for IBS symptom management. You may want to try these simple dietary changes for IBS management before the low FODMAP diet.
Before starting the low FODMAP diet, always talk to your doctor and/or dietitian. Remember, this is a medical diet and meant to be done with the help of a FODMAP educated dietitian. A dietitian will help you to implement the diet, eat a variety of foods, avoid accidentally eating high FODMAP foods, troubleshoot problems and achieve good symptom control.
I hope you feel better soon!
