reintroducing FODMAP foods

There are two distinct phases of the low FODMAP protocol.

The first is the elimination phase that lasts about 2 to 8 weeks. This is followed by the reintroduction phase that lasts about 10 weeks. It is vital to understand how to move through each of these phases to maximize your experience on the low FODMAP diet.

For more information on the elimination phase, please see my previous post on Basic FODMAP Training. Today’s article reviews the systematic approach to reintroducing FODMAP foods.

When is it time to start reintroducing FODMAPs?

This answer varies from person to person.

Some start the low FODMAP elimination diet and notice immediate improvement in their digestive symptoms. They continue on the elimination phase for a minimum of 2 weeks before moving on to the reintroduction phase.

On the other hand, some start the low FODMAP elimination diet and notice little to no improvements after the first 2 weeks. In this scenario, keep a diligent food record to review adherence to the diet. However, it is still important to continue on this phase for a few more weeks.

Overall, do not follow the elimination phase longer than 8 weeks as it results in detrimental effects on digestive tract health:

A paper published in 2105 from the American Journal of Gastroenterology says, “…the long-term benefit of a low-FODMAP approach in large (unselected) patient groups is unclear, especially considering its invasiveness, which requires strict guidance by a dietician, and the potential risks of, for example, reduced fiber intake and changes in microbiota composition and activity.” 

Here’s another article that reviews the benefits of going through the FODMAP reintroduction process.

When and how should I assess my symptoms?

At the end of the low FODMAP elimination diet, perform an assessment of your symptoms.

     Did ANY of your symptoms improve and to what degree?

     Did the frequency of any of your symptoms improve?

In some cases the low FODMAP diet helps reduce the severity of bloating, but does not completely resolve it. In other cases the low FODMAP diet helps improve bowel frequency, but does not completely resolve loose stools. Whatever the case, attach a “report card” to the elimination phase to decide, “Was this diet helpful?”

Finally, do not move forward with the reintroduction phase until symptoms are at least 90% resolved. Otherwise, adding new foods back into the diet becomes muddled with the unresolved symptoms. Consider speaking with a dietitian or other healthcare provider directly if you are still working through the elimination phase without significant relief. 

What foods should I add back in first?

There is no set order for the reintroduction phase.

However, it is important to eventually challenge all of the high FODMAP food categories to avoid staying on a long-term restrictive diet. Keep in mind that you will remain on the low FODMAP diet while you perform all of the reintroduction trials, so again, the order doesn’t make much of a difference!

Are there specific guidelines to follow when I add a high FODMAP food back into the diet?

Yes. It is important to follow a systemized approach when adding high FODMAP foods back into the diet to gain the most insight from the experience.

Remember, not all high FODMAP foods impact people the same way. Responses to these foods are highly individualized and typically based upon the total dose consumed. 

The systemized high FODMAP reintroduction approach involves 10 specific FODMAP trials:

  1. Fructose
  2. Sorbitol
  3. Mannitol
  4. Lactose
  5. Fructan (grain)
  6. Fructan (bread)
  7. Fructan (vegetable 1)
  8. Fructan (vegetable 2)
  9. Fructan (fruit)
  10. Galactan

Each trial lasts about 1 week. Again, the trials do not need to occur in any specific order, but be sure to complete all 10 trials. 

Continue following a low FODMAP diet while completing the trial. The ONLY THING that changes during the reintroduction phase is the addition of the trial food. 

Consume the trial food in titrated doses over 3 days, followed by a 3 day “washout” period. At the end of the trial, assess how you feel and decide if the FODMAP trial food passed or failed. Continue through this process until all 10 trial are completed. 

What is a trial food?

Trial foods are used to test how your body responds to each type of FODMAP. 

They ideally contain only ONE type of FODMAP category.  Remember, FODMAPs are various types of carbohydrates (i.e. lactose, fructose, fructans, polyols, galactan) and some foods on the high FODMAP list contain multiple types of FODMAP categories. For instance, apples contain both fructose and sorbitol (polyol). Also, peaches contain both fructans and sorbitol (polyol). You get the picture!

Acceptable trial foods include the following:

  1. Fructose- honey or mango
  2. Sorbitol- blackberries or avocado
  3. Mannitol- sweet potato or cauliflower
  4. Lactose- yogurt or milk
  5. Fructan (grain)- buckwheat kernels or rice crisp cereal
  6. Fructan (bread)- wheat bread
  7. Fructan (vegetable)- garlic clove
  8. Fructan (vegetable)- leek or onion 
  9. Fructan (fruit)- grapefruit or date
  10. Galactan- peas, black beans or almonds 

How do I perform a trial? 

To perform a trial, pick out the food you plan to use (i.e. blackberries to test your reaction to sorbitol). Have that food on hand for the week.

The trial food is consumed in titrated doses over 3 days while continuing to follow a low FODMAP diet. Make sure to consume the entire recommended dose of the food in one sitting. Doses are listed below. 

Record details of the trial in a food/symptom diary including the type of food, portion size, and time of day it was consumed.  I like using the My Symptoms app to keep your diary organized ($2.99…well worth it!)

Thereafter, follow a 3 day washout period where you no longer consume the trial food. Additionally, follow the low FODMAP diet and assess for any delayed symptoms. Symptoms may occur 30-minutes and up to 2-days after eating the food! Here’s an article that reviews the timing of symptoms in more detail.

If a symptom occurs above your baseline, record the response, remove the food from the diet, and wait until the symptom resolves. Then, when you feel back to “normal,” restart the reintroduction process with a new food trial.

The trial food may be added at any time of day, but ideally when you are at home and able to handle any adverse symptoms that potentially develop. Additionally, it is not advised to trial the food too late at night as it may negatively impact your sleep if the food is poorly tolerated.

Finally, trial foods may be mixed in with your meal (i.e. diced avocado on a salad) or consumed separately (a spoonful of yogurt). As long as you  continue the low FODMAP diet, any symptom experienced will most likely be attributed to the trial food as it is the only “new” change to the diet. 

How much should I eat of each trial food during the FODMAP reintroduction?

Eat the trial food in increasing doses over a period of 3 days. Day 1 is the smallest dose, day 2 is a medium dose, and day 3 is the highest dose. There is no need to eat the highest dose if the smaller doses are poorly tolerated. 

Remember, eat the entire dose in one sitting to know how it makes you feel. 

Trial Doses-

  1. Fructose-
    • Honey- 1 teaspoon, 1 tablespoon, 2 tablespoons
    • Mango- 1/4 medium, 1/2 medium, 1 whole medium 
  2. Sorbitol-
    • Blackberries- 3 berries, 6 berries, 10 berries
    • Avocado- 1/4 medium, 1/2 medium, 1 whole medium 
  3. Mannitol-
    • Sweet potato- 1/2 cup, 3/4 cup, 1 cup
    • Cauliflower- 1/4 cup, 1/2 cup, 1 cup
  4. Lactose-
    • Yogurt- 1/4 cup, 1/2 cup, 1 cup
    • Milk- 1/2 cup, 1 cup, 1.5 cup 
  5. Fructan (grain)-
    • Buckwheat kernels- 50g, 100g, 150g
    • Rice crisp cereal- 30g, 45g, 60g 
  6. Fructan (bread)- 
    • Wheat bread- 1 slice, 2 slices, 3 slices 
  7. Fructan (vegetable)-
    • Garlic clove- 1/4 clove, 1/2 clove, 1 clove
  8. Fructan (vegetable)-
    • Leek- 1/4 medium, 1/2 medium, 1 whole medium 
    • Onion- 1/4 medium, 1/2 medium, 1 whole medium 
  9. Fructan (fruit)-
    • Grapefruit- 100g, 200g, 300g
    • Date- 1 date, 2 dates, 4 dates 
  10. Galactan-
    • Peas/black beans (canned)- 2 tablespoons, 4 tablespoons, 6 tablespoons
    • Almonds- 15 nuts, 20 nuts, 25 nuts 

For more information, please read this post. 

What comes next after I finish the FODMAP reintroduction process?

After your strong commitment to the low FODMAP diet and reintroduction process, start thinking about a maintenance plan.

At the conclusion of the reintroduction process you will have documentation (in your food/symptom diary) of how your body responded to each of the high FODMAP categories. Therefore, if you passed the food trial for a high FODMAP category, then you may start incorporating other foods from that category into your diet. For example, you may now add in mushrooms after you passed the mannitol food trial (using sweet potato or cauliflower).

Refer to your high FODMAP food chart or the Monash University FODMAP app when reincorporating these foods. Additionally, there is no need to add back in any food that you do not enjoy or do not miss, but aim to add back in as many foods as possible.

The goal is to liberalize the diet and include as many fermentable carbohydrates (FODMAPs) as tolerated without provoking gastrointestinal symptoms. 

Some people find that certain foods or combinations of foods are better tolerated than others. This experience is yours; therefore, stay in tune with how your body feels and responds over time.

For more help or individualized care while following the low FODMAP diet, please contact me for an appointment. I am here to make sure this process is painless and offers you the relief you deserve!