5 Myths about the Low FODMAP Diet…Debunked!

1.     It’s a life-long diet

This is perhaps the most common misconception: that you should follow a low FODMAP diet for the rest of your life. This is just a temporary, learning diet and the “low FODMAP” part refers to the first phase of the diet, when you eliminate all high FODMAP foods. As soon as symptoms are reduced and you feel better, you need to re-challenge those foods gradually and systematically to find out your personal triggers. You can then craft your personalized FODMAP diet. Even then, you are not done. As symptoms wax and wane, you are encouraged to re-challenge more foods every 3-6 months.

2.     It’s the same for everyone

I often hear people tell me their doctor gave them a handout and told them to follow the low FODMAP diet. Period. It’s not that simple! This is not just a list of foods to avoid and foods to eat. Sure, a few foods have negligible amounts of FODMAPs and are “included” whereas other are high in FODMAPs and “excluded”, at least during the elimination phase. But so many foods are either low or high depending on their portion size. To complicate matters, there is the question of the FODMAP load in a single meal or snack. Most importantly, every person reacts to different foods and they will end up eating a modified FODMAP diet that is unique for them. This stresses the importance of securing the help of a registered dietitian who is knowledgeable in this topic to help navigate all its complexities.

3.     It’s a gluten-free diet

It is not, as gluten is not a FODMAP. FODMAPs are carbohydrates and gluten is a protein. However, gluten and a certain class of FODMAPs (fructans) coexist in wheat, barley, and rye. This is where the confusion comes. Wheat, barley, and rye and products made with these grains are excluded during the first phase of the diet to eliminate the fructans. In fact, some low FODMAP foods that contain gluten, such as soy sauce, are included. On the other hand, not all gluten-free products are low FODMAP. Many gluten-free breads and other baked products often contain high-FODMAP ingredients such as honey, agave, pear or apple juice, or inulin/chicory, which makes them not suited for a low FODMAP diet.

4.     It’s a lactose-free diet

Lactose is a FODMAP but the diet only needs to be low in lactose, not completely free of lactose. Lactose-free dairy products (milk, yogurt, cream cheese and ice cream) can be included. And so can those with minimal lactose content, for example hard cheeses like parmesan or cheddar, butter, and small amounts of cream and half-and-half.

5.     It’s a low-fiber diet

Finally, some people think they need to avoid all high-fiber foods. This is not true and can be counterproductive for those suffering of constipation. Depending on which kind of motility issue you may have (diarrhea or constipation), the fiber content will need to be adjusted and the type of fiber individualized (more soluble or insoluble fiber). Low FODMAP sources of fiber such as permitted amounts of chickpeas and lentils, low FODMAP vegetables and fruits, and low FODMAP whole grains (quinoa, brown rice, millet, oats, etc.) can and should be included. See my article 5 Tips to Eat More Fiber on a Low FODMAP Diet for more ideas.

3 Tips for Eating a Balanced Vegetarian or Vegan Low FODMAP Diet

FODMAPs are sugars and fibers that are either poorly absorbed or not absorbed at all. A low FODMAP therefore diet restricts the intake of carbohydrate-rich foods such as some grains, legumes, lactose-containing dairy, vegetables and fruits. When you add another restriction – that of a vegetarian or vegan diet, you might even wonder whether there is anything left to eat at all!

With some planning, and the help of a registered dietitian knowledgeable about FODMAPs, vegetarians and even vegans can follow a low FODMAP protocol and eat a balanced diet. As many foods are either eliminated or limited in portion sizes, vegetarians and vegans need to be especially careful in planning meals so to avoid deficiencies in protein, calcium, iron, vitamin B12 and, possibly, fiber.

Here are 3 tips to eat a balanced vegetarian or vegan low FODMAP diet.

1. Don’t skip the protein

Vegetarians are less at risk of eating too little protein as the low FODMAP diet includes eggs, lactose-free dairy products and a few types of cheeses. Vegans need to pay more attention. Each meal should include a low FODMAP source of protein such as legumes (canned lentils or chickpeas), tofu (firm, extra firm), edamame, or tempeh. I recently wrote My Guide to Eating Soy Foods on a low FODMAP Diet (including an Indonesian Tempeh recipe).

Among the low FODMAP grains, quinoa (and quinoa-based pasta), millet and oats are also high in protein - more than rice - and can contribute to the overall protein intake. According to vegetarian-nutrition experts, vegetarians and vegans should aim to eat a little more protein than omnivores: about 1 g/kg body weight (instead of the general recommendation of 0.8 g/kg).

2. Include good sources of calcium

Calcium intake may be an issue for everyone on a low FODMAP diet due to the restriction of lactose. Vegetarians who like dairy products can eat lactose-free milk, yogurt, and a few kinds of hard cheeses. Vegans miss out on this food group entirely but can still meet their calcium needs by drinking calcium-fortified almond or hemp milk, and eating calcium-set tofu, and calcium-rich vegetables (bok choy and kale) and chia seeds. See more ideas in my article, 5 Tips to Eat Enough Calcium (including two tasty calcium-rich recipes).

3. Pump Up the Iron

A common pitfall for all vegetarians/vegans (whether on a low FODMAP diet or not) is eating too little iron. The best sources are, after all, red meat and organ meats. Even so, careful meal planning can help you eat enough or close to enough. All the plant-based protein sources are high in iron (and zinc): legumes, soy products, nuts and seeds. The grains mentioned above are also rich in iron, as well as certain low FODMAP vegetables such as kale, chard, raw spinach, bok choy, and broccoli. 

You may have heard that the iron from plant foods is not as well as absorbed as the one from animal foods. However, adding a vitamin C-rich fruit or vegetable (for example, kiwi, strawberries, oranges, or red bell peppers and broccoli) at the same meal greatly increases the absorption of iron. Another useful tip is to avoid drinking coffee, tea, mint tea or cocoa with meals as the flavonoids or phenolic acid in these beverages bind the iron and reduce its absorption by as much as 50-90%. Finally, it would be best to eat calcium-rich and iron-rich foods in separate meals, as calcium and iron inhibit each other’s absorption. You need not worry about the foods that contain both (such as tofu or legumes). Mostly try not to drink lactose-free milk or almond milk with your lunch or dinner, and have those very high-calcium foods with breakfast and/or snacks.

Final Food for Thought…

A paper published by Monash University earlier this year found some popular vegan foods to have either a low or negligible FODMAP content: soy cheese, coconut yogurt, pea protein isolate, kelp noodles, vegan egg replacer, nutritional yeast, agar-agar, dulse, and spirulina. Check out the Monash University FODMAP Diet App for appropriate serving sizes.

Even when doing all things right, you may still be deficient in certain of these nutrients or may simply not be eating enough. It’s best to consult with a registered dietitian trained on the low FODMAP diet to see whether you may need to tweak your meals further or need a supplement (for example, B12 for vegans). Finally, don’t forget that the low FODMAP diet is a temporary diet and, once you have completed the re-challenge phase, you may be able to include many more foods, such as more varieties of beans and lentils, perhaps soy milk, and more vegetables.


My Guide to Choosing Soy Foods on a Low FODMAP Diet

Soy foods can be an important source of protein and other nutrients for vegetarians and vegans and a way to break away from the routine of eating animal protein for everyone else. Even Monash University recently recognized the importance of eating less animal protein by starting a Meat Free Week campaign on Instagram and posting one vegetarian a recipe a day for a week on their blog.

Soy beans are indeed a source of FODMAPs - mostly galacto-oligosaccharides (GOS) and some fructans - and not allowed during the elimination phaseSoy milk that is made from soy beans (and soy yogurt, which is made from soy milk) is also high in FODMAPs, as it is made by grinding the beans and water together. Incidentally, there is a type of soy milk made from soy protein which is low in FODMAPs. It is popular in Australia but here in the US it is not as easy to find. The only brand I came across is 8th Continent but all their varieties are high in sugar and one of them also contains inulin.

Many of the products made from soy beans, however, become low FODMAP because of what happens during the food processing. As I described in a recent blog article, it turns out that the FODMAPs in soy are soluble in water. Hence, any technique that involves soaking the soybeans in water and straining them will allow the FODMAPs to leach into the water and considerably lower the FODMAP content of that food. This is the case with firm tofu. On the other hand, silken tofu is not drained and retains all the water and the FODMAPs. 

Another food processing technique that lowers FODMAP content is fermentation. This explains why plain tempeh (made from fermenting soy beans) is low in FODMAPs. Some varieties also have grains like rice or millet but most are free of wheat/gluten. Watch out for added high FODMAP ingredients like garlic, onions, or celery. See my Indonesian Tempeh Randang recipe for a tasty way to eat this less-known and appreciated soy food.

A second consideration when choosing soy products is that GOS and fructans are fibers, and the foods that are lower in fiber are also lower in FODMAPs. Immature soybeans (edamame) are an example. Monash University tested them and found them suitable in small amounts.

Soy burgers or meat substitutes have not been tested but most likely are high in FODMAPs as they may contain the fibers from soybeans. Textured soy protein, the main ingredient in many soy-based meat substitutes is high in FODMAPs. Soy protein powder may be low in FODMAPs depending on how it is processed. It is best to avoid it during the elimination phase as its FODMAP status is unknown.

Soy lecithin and soybean oil are not a source of FODMAPs and are ok. Soy sauce has been tested and found to be low in FODMAPs.

In summary, use this guide to navigate the soy aisle and don’t be afraid in experimenting with soy foods. 


  • Tofu (firm or extra firm)

  • Plain Tempeh (no extra high FODMAP ingredients)

  • Edamame

  • Soybean oil

  • Soy sauce


  • Soy beans

  • Soy milk (made from soy beans)

  • Soy yogurt

  • Silken tofu

  • Soy burgers/meat substitutes

  • Textured soy protein

  • Soy protein powder

Check out the Monash University App for appropriate serving sizes.

If, after completing the re-challenge phase, you find that you can tolerate GOS and fructans, you can experiment with the high FODMAP soy foods.

Tempeh Randang


2 inch- stalk of lemongrass (from the bottom white part), roughly chopped
2-inch piece of ginger, peeled, roughly chopped
2 tbsp water

1 tbsp sunflower seed or canola oil
8 ounces/225 g tempeh, cut into ½-inch pieces

½ lb. small red potatoes, scrubbed and cut into ½-inch cubes
¾ tsp ground fennel seed
½ tsp ground cardamom
¼ tsp ground cloves
½ cinnamon stick (about 2 inches)

1 small can (5.46 oz/160 ml) unsweetened coconut milk
½ cup water
½ tsp salt
A few grinds of black pepper 


1. Blend the lemongrass stalk and ginger with 1 tablespoon of the water. Scrape the sides of the blender, add the additional tbsp of water and blend until you have a paste (it will be a rough paste, due to the fiber in the lemongrass, but that’s ok).

2. In a nonstick skillet, heat the oil over medium high heat and sauté the tempeh until browned, about 3-5 minutes per side. Add the dry spices, cinnamon stick, the lemongrass-ginger paste and a little water, and sauté for 2 more minutes. Add the potato, coconut milk and water. Bring to a boil, lower the heat, cover, and simmer until the potato is tender, about 5 minutes, stirring occasionally.

3. Remove from the heat, season with the salt and pepper, and serve over red or brown rice.  


4 servings


Store in an airtight container in the refrigerator for up to 4 days.


Antonella Dewell, Registered Dietitian Nutritionist and Natural Chef