Debunking Low FODMAP Diet Myths

This post is by Mel Spinella with support from me! – Kate Scarlata MPH, RDN. 

Mel has a Master of Science degree in Nutrition Education from Teachers College, Columbia University and is working towards becoming a registered dietitian.

The Low FODMAP diet (LFD) has been shown to improve gastrointestinal symptoms in about 50-70% of people with irritable bowel syndrome (IBS). Given the fair amount of misinformation online regarding the low FODMAP diet, attempting to do the diet on your own can be a challenge. In this post, I will be debunking some myths about  the LFD to better set you up for success. Of course, as a reminder, do not self diagnose yourself with IBS, always consult your healthcare provider before changing your diet. It’s important to note that science has shown that a low FODMAP diet has better compliance and appropriate application when guided by a dietitian.(1)

Myth 1: The Low FODMAP Elimination Diet is a Long-Term Diet

The purpose of the LFD is to identify your personal IBS dietary triggers to guide the best diet for your body for IBS symptom management. The elimination phase of the diet does not need to and should not be followed forever. This diet should progress through all 3 phases of the LFD: the elimination phase, the reintroduction phase, and the personalization phase. Ideally, each phase is applied with the guidance of a registered dietitian who specializes in the LFD to ensure the diet is applied appropriately, is nutritionally complete and is easier to follow. 

During the elimination phase (2-6 weeks), all high FODMAP foods are eliminated from the diet. (2,3) Following the elimination phase, a dietitian will guide you through the reintroduction phase (6-8 weeks), where FODMAP subtypes (e.g. lactose, excess fructose, fructans etc.) will be reintroduced back into the diet, one at a time. (2) The reintroduction phase is important as it helps identify your personal dietary triggers and your tolerance to various FODMAP-containing foods. The last phase of the diet is the personalization phase. During this phase, foods that were tolerated in the reintroduction phase are added back into the diet. The personalization phase is followed as needed for symptom management. (2,3) 

Many people learn that they only need to restrict some high FODMAP foods. In fact, there have been two studies specifically looking at what FODMAPs are most likely to trigger GI symptoms in IBS. One reintroduction study, undertaken by Michigan Medicine researchers, found that the most common triggers were fructans and galacto-oligosaccharides.(4) Another study from KU Leuven, found that fructans and to a lesser degree, mannitol were the FODMAP subtypes that triggered IBS symptoms most commonly in the patients they studied.(5)

Tolerated FODMAP subtypes can and should be added back to your diet. Many FODMAP-containing foods are nutritious foods and some contain prebiotic fibers, which promote growth of probiotic flora, shown to offer health benefits. Merely following the elimination phase of this diet, without continuing to the reintroduction and personalization phases, is unnecessarily restrictive and may lead to deleterious gut microbiome changes. The overall goal of the LFD is to find a diet with as much variety as possible, while still managing IBS symptoms. 

Myth 2: Food Sensitivity Tests are the best way to test for FODMAP sensitivities

Despite their popularity, food sensitivity tests lack scientific evidence to be used broadly to diagnose food intolerances. Due to the lack of evidence to support their use and validity, they are not recommended or evidence-based in IBS at this time. The results of these tests may lead to unnecessary food restriction and even increase risk of food fears. Restrictive elimination diets can unnecessarily decrease nutrient variety in the diet and have the potential to lead to disordered eating behaviors as food fears can emerge when a long list of foods to avoid is presented to the patient.  

It is important to work with a GI-expert dietitian to determine your specific trigger foods and only limit foods that prompt GI distress.

To learn more about why food sensitivity tests are not evidence-based, take a look at Kate’s Food Intolerance vs. Food Allergy post here.

Myth 3: The Low FODMAP Diet is low in fiber

According to the Monash University blog, consuming enough fiber can help reduce symptoms of constipation and abdominal pain in people with IBS. (6). Although reducing intake of wheat and fibrous, high FODMAP vegetables may prompt a reduction of fiber intake, a LFD can still provide adequate fiber to meet your needs. In fact, a LFD allows all food groups. When the LFD is applied with guidance from a registered dietitian, it can be nutritionally adequate and fiber rich.

The list below provides low FODMAP foods and their fiber content. (7)

Fruits and Vegetables

• Two small, peeled green kiwifruit – 4 grams of fiber
• ¾ cup raw broccoli, raw – 2 grams of fiber
• 1 medium carrot – 3 grams of fiber
• 1 medium, peeled orange- 3 grams of fiber
• 1 cup chopped pineapple – 2 grams of fiber
• ¼ cup pomegranate seeds – 3 grams of fiber
• 30 raspberries – 3 grams of fiber
• 1 cup raw spinach – 1 grams of fiber

Nuts and Seeds

• 2 tablespoons of chia seeds – 8-10 grams of fiber 
• 1 tablespoon of flaxseeds – 3 grams of fiber
• 2 tablespoons peanut butter-2 grams of fiber
• 2 tablespoons pepitas-2 grams of fiber

Whole Grains

• ½ cup uncooked, rolled oats – 4 grams of fiber
• 1 cup cooked quinoa – 5 grams of fiber
• 1 cup cooked brown rice – 3 grams of fiber

Protein

• ⅔ cup cubed, firm tofu – 2-4 grams of fiber

How much fiber do you need?

Recommended fiber intake varies based on gender and age. The Dietary Guidelines For Americans 2020-2025 recommends the following daily fiber intake: (8)

Fiber recommendations per day for women:

• Ages 19-30: 28 grams
• Ages 31-50: 25 grams
• Ages 51+: 22 grams

Fiber recommendations per day for men:

• Ages 19-30: 34 grams
• Ages 31-50: 31 grams
• Ages 51+: 28 grams

Myth 4: You can’t apply intuitive eating strategies on the Low FODMAP diet

Let’s start with a quick introduction. Intuitive Eating is a self-care eating framework created by two dietitians, Evelyn Tribole and Elyse Resch in 1995.  IE is based on 10 principles and the IE framework has been explored in numerous studies. IE is science-based and shown to promote positive health outcomes for both psychological and physical well-being.(9)

It is possible to practice intuitive eating (IE) while on the LFD. Again, the elimination part of the LFD is temporary and serves to assess if you have FODMAP sensitivities. The reintroduction phase serves to identify what FODMAP sensitivities you may be experiencing. Following the reintroduction phase, your diet is personalized based on the foods that were well- tolerated and made you feel good. Eating foods that are healthy for you, can make you feel good. And who doesn’t want to feel good?

One of the IE principles is, “Honor your Health with Gentle Nutrition”.  While in the “learning phase of a low FODMAP diet” one may not be self guided with diet choice by tuning in to how food feels in your body, but rather by “a list” of low FODMAP foods to consume. The ultimate goal of a LFD, however, will be to tailor the diet based on your body’s feedback–both physical and emotional.  Interoceptive awareness–part of the foundation of IE, is the ability to feel physical sensations in the body. These sensations can help guide your eating patterns on a biological basis vs. a food list. (9) The goal is to transition from “a food list” to a tailored personalized approach as you tune in to see what foods work for you- for your mind and in your body.

For more information on intuitive eating and the Low FODMAP diet, take a look at the Intuitive Eating and Body Kindness for Gut Health + Beyond post. 

Remember, it’s important to eat in a way that doesn’t cause undue stress and anxiety. Diet-related stress and anxiety can actually worsen symptoms of IBS–and make diet change counterproductive.  If possible, work with a registered dietitian who specializes in the LFD. You can find FODMAP knowledgeable dietitians here. An RD can be extremely helpful to personalize your diet and help guide you in listening to your body. While knowing which FODMAPs aren’t well-tolerated is important, it’s also important to focus on which foods are well-tolerated. For more information on this, take a look at Kate’s Low FODMAP Checklist and also the Monash App, which provides more information about Low FODMAP foods and portion sizes.

Remember diet interventions is just one way to work on symptom management in IBS. To learn more about the gut-brain connection and non-diet therapies to treat IBS, read the Gut-Directed Hypnotherapy for IBS and The Role of a GI Psychologist for IBS posts.

References:

1. Tuck CJ, Reed DE, Muir JG, et al. Implementation of the low FODMAP diet in functional gastrointestinal symptoms: A real-world experience. Neurogastroenterol Motil. 2020 Jan;32(1):e13730.  
2. “Starting the Fodmap Diet.” Starting the Low FODMAP Diet – Monash Fodmap, https://www.monashfodmap.com/ibs-central/i-have-ibs/starting-the-low-fodmap-diet/.
3. Haller E, Scarlata K. Diet Interventions for Irritable Bowel Syndrome. Gastroenterol Clin N Am. 2021; https://doi.org/10.1016/j.gtc.2021.03.005
4. DDW 2021 Poster Eswaran S, Singh P, Rifkin S DDW 2021: Are all FODMAPs created equal? A blinded, randomized reintroduction trial to determine which FODMAPs drive clinical response in IBS patients.
5. Van Den Houte K et al. Efficacy of a new approach to the reintroduction phase of the low FODMAP diet in IBS. GASTROENTEROLOGY; 2021; Vol. 160; iss. 6; pp. S76-77
6. Varney, Dr Jane. “Getting Enough Fibre.” Monash Fodmap, Monash Fodmap, 14 Jan. 2021, https://www.monashfodmap.com/blog/getting-enough-fibre/. 
7. https://fdc.nal.usda.gov and product food labels
8. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition. December 2020.
9. Tribole, Evelyn, and Elyse Resch. Intuitive Eating, 4th Edition. St Martin’s Press, 2020.