Is a Low FODMAP Diet a Healthy Diet?

This is a question I get a low from my clients, worried that this may be just another fad diet. The low FODMAP diet was created by the researchers at Monash University in Australia to alleviate symptoms in people with Irritable Bowel Syndrome (IBS). It is currently considered the best dietary approach for this condition and several research studies have shown it is successful in 50-80-% of people with IBS. 

The answer to the question “is the low FODMAP diet healthy” depends on how it is implemented. Let me digress for a moment to a better-known diet concept, that of a vegan diet. Most people would think that the vegan diet is very healthy as it brings to mind pictures of environmentally friendly, animal-loving people feasting on salads, nuts, and tofu.

However, the definition of vegan diet verges on what it excludes – all animal products – rather than what it includes – plant-based foods. You could, in principle, be eating French fries, cookies made without eggs or butter and drink sodas and you would be considered a vegan. Although I have exaggerated with this example (at least I hope so!), you get the idea: having a bagel with jam for breakfast, a vegan burger on a white bun with lots of ketchup for lunch and a big plate of pasta with tomato sauce for dinner may be closer to what uninformed vegans may be eating and hardly be called a nutritious diet.

Going back to the low FODMAP diet, whether it is healthy or not depends more on what you include than what you exclude. The low FODMAP protocol teaches you to avoid high FODMAP foods (at least during the elimination phase) or minimize them according to tolerance once you have figured out your own personalized FODMAP diet. Many people, however, end up avoiding all high FODMAP foods long term either because they are afraid of re-challenging them or they don’t know that the low FODMAP diet is not supposed to be a life-long diet. And, especially during the elimination phase, they may get into a routine of eating the same few types of vegetables and fruit, or avoiding some foods, like legumes and dairy altogether.

The message I am trying to bring home here is that a poorly planned low FODMAP diet can lacking in important nutrients like calcium and B vitamins, and in fiber. Working with a dietitian who is an expert in the low FODMAP diet can help you avoid this common mistake. Here are a few questions you may ask yourself to get an idea about how healthy your low FODMAP diet is:

1. Am I eating enough fiber?

You don’t need a nutrition software to know whether you are eating enough fiber. Write down what you eat for a few days or a week and look back at your diary: are you eating vegetables at your main meals and at least one snack? Are you occasionally eating low FODMAP servings of canned lentils or chickpeas? Are you including some nuts and seeds? See my 5 Tips to Eat More Fiber on a Low FODMAP Diet for more ideas. 

2. Am I eating enough calcium?

Contrary to common belief, the low FODMAP diet is not a lactose-free diet. It is a low lactose diet and can include small portions of some hard cheese and cream cheese. Small amounts of lactose can be tolerated even by lactose-intolerant people. It is not a dairy-free diet either and you can eat plain lactose-free dairy freely. If you are avoiding dairy for other reasons (allergy to milk protein, ethical reasons, or you just don’t like them), there are many alternative calcium sources. And, yes, even vegans can eat enough calcium if they plan their diet well.

3. Am I eating the colors of the rainbow?

Is your diet white and red (gluten-free pasta and tomatoes) or do you choose vegetables and fruit with all the colors of the rainbow? This is an easy way to ensure you get the bounty of vitamins, minerals, and phytochemicals that vegetables and fruit have to offer. Chard, kale, spinach, carrots, red peppers, eggplant, kabocha and summer squash are just some of the vegetables that have either negligible or small amounts of FODMAPs and can be eaten freely or in fairly large portions. Fruit can be usually enjoyed in half-cup portions per meal or snack. In the spring and summer, strawberries, raspberries, blueberries and cantaloupe or honeydew are great low FODMAP choices, whereas in the fall/winter look for the citrus fruits and kiwi just to name a few.

If you answered yes to all these questions – great job! If you answered no to at least one of these questions, try some of the suggestions above and look at the Monash University Low FODMAP Diet App for guidance on foods and serving sizes.

Prebiotics: How To Keep Your Friendly Bacteria Happy on a Low FODMAP Diet

Prebiotics are types of fiber that go undigested through the GI tract, are quickly fermented by the bacteria in our gut and stimulate their growth and activity (think of them as their favorite food).  This is, in general, a good thing, as these friendly gut bacteria confer a number of health benefits.  For example, they keep at bay the “bad” bacteria, and can aid in the absorption of minerals and benefit the immune system. The downside is that, as bacteria feast on this food, they also produce gas. In healthy people this is no more than a “nuisance” but in people with IBS, the bacteria produce excess gas or flatulence, which can be painful and life-disrupting. 

The low FODMAP diet minimizes the intake of prebiotics to reduce IBS symptoms. As such, it reduces the amount of food available to the friendly bacteria in our gut, leaving them potentially "starving".

Studies that have looked at the impact of a low FODMAP diet on gut bacteria have shown that after only 3 or 4 weeks on the elimination phase, both the amount and variety of good bacteria are decreased. One study also showed that there was an increase in bad bacteria.

Should you be worried? Yes and no. For starter, no-one should be in the elimination phase for more than 4-6 weeks. While you are in that strict phase you are not supposed to completely eliminate all probiotics but to minimize them. You can eat small portions of prebiotic-rich foods and keep your gut bacteria from "starving" too much. 

Here are a few examples of foods that confer some prebiotics but are still considered “low FODMAP” (at the “green” serving size, according to the Monash University Low FODMAP Diet App):

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  • Vegetables: potatoes (cooked and cooled as in a potato salad), savoy cabbage, eggplant, canned baby corn

  • Fruit: green or firm bananas, kiwi, citrus fruits, and pomegranate seeds

  • Whole grains: raw rolled oats; buckwheat groats, brown rice, and quinoa, cooked and cooled, as in a grain salad.

  • Legumes: canned chickpeas and lentils (1/2 cup)

  • Nuts: almonds and hazelnuts; tigernuts - not really a nut but a tuber

Finally, once you start re-introducing higher FODMAP foods, you may find that you can re-introduce some of the prebiotic fibers (oligosaccharides). The goal is to find a good balance between keeping symptoms at bay and eating some prebiotics to achieve the right equilibrium of gut bacteria. The good news from research in this field is that, once people start eating more prebiotics, the gut population grows back strong!

5 Tips to Eat More Fiber on a Low FODMAP Diet

We all know fiber is a good thing. We keep reading articles about it in magazines and see packaged foods boasting "high fiber" claims in bold letters. Indeed, fiber has several health benefits: it helps our intestines function regularly and may help lowering cholesterol and blood sugar levels. 

People with IBS need to be careful about the amounts and types of fiber they eat so not to experience unwanted symptoms. Certain fibers are rapidly fermented in the large intestine and may lead to bloating, abdominal pain and excess gas. A few examples of foods that contain these types of fiber are onions, artichokes, wheat, and beans. These are the fibers a low FODMAP diet is designed to minimize.

Other types of fiber are slowly fermented and better tolerated, for example, the fiber in brown rice, kiwis, raspberries, carrots, and chia seeds.

How much fiber do we need? According to the Dietary Guidelines for Americans, and adequate fiber intake is 25 g per day for women and 38 g per day for men up to the age of 50 (a little less for older people). This is, however, for the general (healthy) population (sadly, most Americans consume too little fiber, an average of 15 g per day). Monash University recommends people with IBS eat between 25 and 30 g of fiber per day.

Here are 5 tips to eat more fiber:

1.     Don't be afraid to consume some fiber. Remember, this is a low FODMAP diet, now a zero FODMAP diet. On the other hand, don’t overdo it. Depending on your IBS subtype and symptoms (diarrhea or constipation), you might need to be on the low or high end of those recommendations. As you increase your fiber intake, make sure to also drink enough water during the day.

2.     Be sure to choose low FODMAP whole grains (brown rice, millet, quinoa) and don't limit yourself to the "white" stuff. There is a tendency for people to gravitate towards either avoiding grains altogether or mostly eat white rice, white-rice flour based products (crackers, gluten-free bread). By including more whole grains, in addition to the fiber (2-4 grams per cup of cooked brown rice, quinoa, quinoa-corn pasta or millet), you will get other important nutrients as well.

3.     Choose a variety of low FODMAP fruits and vegetables (keep the skin on) in small portions (1/2 cup is a good benchmark and will provide 2-4 grams of fiber) and spread them out throughout the day. Try some of these:

  • Fruit: raspberries, blueberries, strawberries, kiwifruit, oranges

  • Vegetables: carrots, radishes, kale, Swiss chard, eggplant

4.     Some canned legumes are ok even during the elimination phase (rinse and drain first). Try up to ½ cup per meal or snack (5-8 grams of fiber):

  • Lentils (great in soup, salads or chili)

  • Chickpeas (they are delicious roasted as a snack or sprinkled on salads)

  • Fresh or frozen edamame (boiled and rinsed)

5.     Don’t forget the nuts and seeds. In small amounts, these can contribute good amounts of fiber without triggering symptoms. Try up to 2 tablespoons per meal or snack (1-2 grams of fiber in most nuts/seeds; 10 grams in chia seeds):

  • Nuts: almonds or walnuts – great sprinkled on hot rice/quinoa cereal for breakfast

  • Seeds: pumpkin seeds (good by themselves or as topping for tacos) and chia seeds (in a smoothie or as chia pudding – see my recipe for Cocoa Chia Pudding below - who thought that eating more fiber could look like this?)

Finally, if you feel you need a fiber supplement, consult a dietitian before trying one on your own. If you choose the wrong fiber, you may make your symptoms worse. An expert dietitian can recommend one most suitable to your IBS subtype.

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Cocoa Chia Pudding


1 ½ cups unsweetened almond milk

¼ cup chia seeds

1 tablespoon unsweetened cocoa or raw cacao powder

1 packet powdered stevia (1 g)

1 teaspoon vanilla extract

A few chocolate shavings or 2-3 raspberries per serving to top (optional)


1.     Combine the almond milk, chia seeds, cocoa, stevia, and vanilla extract in a bowl. Whisk until well combined and the mixture begins to thicken. Cover the bowl with plastic wrap and let sit in the refrigerator overnight or for 6-8 hours.

2.     When the pudding has set, give it one more stir, then portion into single-serve bowls. Alternatively, heat up in the microwave for a warm pudding.

3.     You can top with a small amount of shaved chocolate or 2-3 raspberries per serving, if desired.

Yield: 2 servings

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

Author: Antonella Dewell, Registered Dietitian Nutritionist & Natural Chef