How to Follow the Low-FODMAP Diet

Many doctors are now routinely recommending the low-FODMAP diet to their irritable bowel syndrome (IBS) patients. This is because the diet is the first food-based treatment that has research support for effectively reducing IBS symptoms of gas, bloating, diarrhea and constipation.

With good compliance and support, approximately 70% of IBS patients will experience significant symptom relief.

The diet is a bit tricky and will require a commitment on your part to ensure that you are choosing foods consistent with the diet. Therefore you will not want to take on the diet during a time when you will be extra busy or have limited time in your schedule for food prep and packing.


Find a Trained Professional

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All of the research to date on the diet indicates that the best results are achieved when you get support from a qualified dietary professional who is well-versed in the diet. A dietitian or health coach is important because:

  • You need to make sure that you are eating a wide variety of foods to ensure that you are taking in your daily nutritional requirements.
  • It will be helpful to have support as you learn to integrate the diet into your life.
  • They can help you best determine which of the FODMAP types are problematic for you.

Start a Food Diary

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As you work through the various phases of the diet, you will want to keep a food diary. This will help you get a better sense of the relationship between the foods that you eat and the symptoms that you experience. This step will be especially helpful as you work through the various phases of the diet.

A food diary doesn't have to be anything fancy. You just want to keep track of everything you have eaten, what symptoms you are experiencing, and any other factors that might be affecting how you feel, such as stress, your menstrual cycle, etc.


Gather Your Resources

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It can be very challenging to remember which foods are low in FODMAPs and which foods are high in FODMAPs and just as challenging to find the right foods to eat. Luckily, the success of the diet has spurred the development of available resources.

The low-FODMAP smartphone app from the researchers at Monash University is a must-have. It can also be helpful to purchase some low-FODMAP cookbooks and frequently visit sites that have low-FODMAP recipes. The more food options you have, the more likely you will be to comply with the diet's guidelines.


Start the Elimination Phase

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To start the diet, you will need to totally eliminate known high FODMAPs foods for a period of four to six weeks. This includes foods from the following FODMAP sub-groups:

  • Fructans: Found in some fruits, grains, nuts, and vegetables
  • Fructose: Found in some fruits
  • GOS: Found in beans, chickpeas, and lentils
  • Lactose: Found in some dairy products
  • Polyols: Found in some fruits, vegetables, and artificial sweeteners

What is left to eat? Plenty of delicious, nutritious things. You can eat anything you want as long as it is low in FODMAPs.


Slowly Reintroduce FODMAPs

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After you have hopefully enjoyed a significant decrease in symptoms, it is time to slowly reintroduce some foods back into your diet. For this reintroduction phase, it is recommended that you pick one FODMAP sub-group at a time to assess the effect of each group on your body.

Your dietary professional can help you to figure out what foods you can test your sensitivity on. Plan to test each group for a week before moving onto the next group. Start with small amounts of foods so as to not cause severe symptoms.

If you experience no symptoms in response to your challenge foods, you can slowly start to increase the quantity you are eating. If you continue to tolerate the food, then you can conclude that you are not reactive to that particular sub-group and you can continue onto the next group.

If you experience symptoms, you can try to test a different food from within the same sub-group. If you continue to have a reaction, you should go back to the elimination diet for one week before moving on to the next sub-group.

After you have tested all sub-groups and have been relatively symptom-free for some time, you will want to re-test small amounts of the sub-group that you were initially reactive to.

Once you have a good sense of which FODMAPs you are most reactive to, you can organize your diet so as to eat predominantly low-FODMAP, with minimal consumption of high-FODMAP foods. The goal is to keep your exposure to FODMAPs in a range that does not cause you to experience symptoms.


Keep Testing Your Range of Foods

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The low-FODMAP diet is not designed to be a "forever" diet. Many foods that are high in FODMAPs are also foods that can be very good for your health.

There are some concerns that FODMAP restriction can have a negative impact on your gut flora. The best thing for both your overall and your digestive health is to eat as wide a variety of healthy foods that you can.

There is some evidence that once you have followed the low-FODMAP diet you will improve your ability to tolerate previously troublesome foods. Therefore, you will want to be sure to keep re-introducing new foods into your diet at regular intervals to see if your sensitivities have changed.

One helpful way is to set a reminder in your day planner or on your smartphone to go through the reintroduction phase again every three months.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. O'Keeffe M, Lomer MC. Who should deliver the low FODMAP diet and what educational methods are optimal: a review. Journal of Gastroenterology and Hepatology. 2017;32:23-26. doi:10.1111/jgh.13690

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  5. Hill P, Muir JG, Gibson PR. Controversies and recent developments of the low-FODMAP diet. Gastroenterology & hepatology. 2017;13(1):36-45.