Figuring Out Tricky FODMAP Foods

The low FODMAP diet, an ideal approach for those with IBS, is a challenging diet to undertake.

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Not only do you need to have a thorough understanding of high FODMAP foods to avoid, but you also need to be familiar with the right portion. Complicating matters further, some tricky FODMAPs foods even require you knowing how the food was processed.

This article helps you figure out the these trickier foods to know whether or not they’re FODMAP-friendly. 

Basics of the low FODMAP diet:

The low FODMAP diet, created by Monash University in 2005, restricts the intake of fermentable carbohydrates to help improve symptoms associated with IBS. In fact, 50 to 86% of IBS patients have a clinically significant response to the diet (1).

There are various types of high FODMAP carbohydrates including dairy products, fruits, vegetables, grains, legumes and even sweeteners. More specifically, the diet classifies these carbohydrates into the following categories:

  • Lactose
  • Fructose
  • Fructans
  • Galactooligosaccharides (GOS)
  • Polyols

Essentially, these foods provoke IBS symptoms by producing excess gas (fermentation) and pulling excess water into the bowel (osmotic effect).

For a checklist of high and low FODMAP foods, go here. 

Tricky FODMAP Foods:

Unfortunately, this diet is so not completely straightforward.

While one may imagine it’s easy enough to avoid a list of foods, the FODMAP diet also considers the portion and the preparation of the food as measures of its fermentability. There is a learning curve involved when starting the diet, which is why most FODMAP resources strongly recommend working directly with a Registered Dietitian Nutritionist (RDN). 

Now, let’s review some of the tricky FODMAP foods that often confuse newbies and even veterans of the diet. This report is based on the findings of the lab at Monash University, which can be found on their FODMAP phone app

1. Soy

Soy is found in many forms in our food system.

Depending on how the soy is processed reflects whether it is a high or low FODMAP food. Typically, soybeans contain both GOS and fructans. However, these compounds are water soluble, meaning they dissolve in water. Therefore, soy foods that remove most of the water content are less likely to contain high FODMAP levels.

Additionally, soy products that are fermented and/or do not contain the carbohydrate-portion of the soy are also considered low in FODMAP levels. 

  • Low FODMAP Soy Foods:

    • Edamame (1 cup)
    • Firm or extra firm tofu
    • Tempeh (fermented soy) 
    • Soy sauce
    • Miso paste (12g)
    • Soy milk made with soy protein only (i.e. 8th Continent)
    • Soy oil
    • Soy protein isolate 
    • Soy lecithin 
    • Soy cheese
  • High FODMAP Soy Foods:

    • Soy flour
    • Mature soybeans
    • Silken tofu
    • Soy milk made with whole soybean
  • Questionable FODMAP Content

    • Soy protein 
    • Soy yogurt 

2. Sourdough bread

It is well accepted that wheat, barley, kamut, spelt and rye are high FODMAP grains. 

With the creation of sourdough bread, the fermented flour from these grains are lower in FODMAP levels. The caveat is the FODMAP content can vary depending on the brand of these breads!

Tips for picking low FODMAP sourdough:

  • Pick breads leavened with sourdough culture, also referred to as “slow leavened” breads. On the same note, avoid products that contain yeast as they are typically faster to rise and contain higher FODMAP levels. 
  • Consider trying a small portion of sourdough bread to test your tolerance.
  • Here’s a good brand: Iggy’s Francese

3. Dairy 

Dairy can be a tricky FODMAP food because not all dairy contains high lactose levels.

The fermentation of milk as well as the removal of liquids in dairy products removes most of the lactose. Additionally, the low FODMAP diet is not 100% free of all lactose. Therefore, small amounts (<1g per serving) of lactose is still considered low in FODMAPs.

Here’s an excellent resource summarizing the lactose content of various cheeses. Keep in mind that lactose is a type of sugar or carbohydrate. Therefore, check the label of the dairy product for the carbohydrate content. If it contains 1 gram or less of carbohydrates, than it is probably a safe bet!

  • Low FODMAP Dairy Foods:

    • Hard or aged cheeses (i.e. Cheddar, Swiss, feta, Brie, semi-soft goat cheese, etc.)
    • Cottage cheese 
    • Lactaid milk 
    • Lactaid yogurt and ice cream (check the label for other potential high FODMAP ingredients like inulin, chicory root, high fructose corn syrup (HFCS), etc.)
    • Whipped cream
    • Half and half
    • Butter
  • Moderate FODMAP Dairy Foods:

    • Cream cheese (2 tablespoons)
    • Ricotta cheese (1/4 cup)
    • Sour cream 
  • High FODMAP Dairy Foods:

    • Regular milk 
    • Ice cream
    • Yogurt (can vary depend on the fermentation process)

4. Corn

Corn is another food that presents in different forms in our food system and creates confusion in the FODMAP diet.

Corn typically contains GOS and sorbitol. However, the processing and the portion help decipher if corn is on the high or low FODMAP list. Keep in mind that products containing corn fiber have an unknown FODMAP level since this type of fiber has not yet been tested in the lab. 

  • High FODMAP Corn:

    • Sweet corn like on the cob or fresh kernels
      • *limit to 1/2 cob or 1/2 cup of kernels to become low FODMAP food
    • Corn flakes (cereal)
      • *limit to 1/2 cup to become low FODMAP food
  • Low FODMAP Corn:

    • Corn oil
    • Corn flour, cornmeal and polenta 
    • Popcorn
    • Corn tortillas

5. Tomato

When I first started learning about the FODMAP diet, condensed tomato products were classified as high in fructose content. Times have changed with updated research. Now, most tomato products are on the low FODMAP list.

The only product to be aware of are sun-dried tomatoes, so keep your portion to 2 pieces. Additionally, many tomato products like marinara sauce, ketchup and canned tomatoes often contain garlic, onions and HFCS for extra flavor so make sure to check labels for these high FODMAP ingredients.

Here’s a low FODMAP marinara sauce to try out.

6. Coconut

Coconut foods are growing in popularity and are consumed in various forms.

Coconut can contain GOS, fructose and polyols. Based on the portion and the processing of the coconut product, the FODMAP content varies. 

  • High FODMAP Coconut Foods:

    • Canned coconut milk (if it contains inulin and if using >1/2 cup)
    • Coconut flour
    • Coconut water (varies depending on processing and added ingredients)
  • Low/Moderate FODMAP Coconut Foods:

    • Coconut flesh (limit to 1/2 cup)
    • Coconut oil
    • Coconut milk yogurt 
    • Dried coconut flakes (limit to 1/4 cup) 
    • Coconut sugar 

Takeaway Tips: 

The low FODMAP diet can be tricky to follow. 

While it’s a good idea to familiarize yourself with the high and low FODMAP food lists, it’s also important to refer to the Monash University FODMAP app or website for a more thorough reference. 

Keep in mind that portion and processing play big roles in the FODMAP content of foods. The portion is represented per meal; therefore, FODMAP meal planning is an important part of the elimination phase of the diet. 

Before starting a low FODMAP diet, consult with a dietitian (like myself) to ensure a successful experience.

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