What is the FODMAP Diet? Your Guide to Feeling Better with IBS

Curious about the FODMAP diet? Learn what it is, how it works, and which foods to eat or avoid to manage IBS symptoms and support your digestive health.

What is the FODMAP diet graphic with colorful images of low FODMAP foods.

Do you suffer from IBS? If so, you know how painful the gas, bloating, and other gastrointestinal symptoms can be. Not to mention, IBS (irritable bowel syndrome) can take over your life.

As a MONASH FODMAP-trained registered dietitian, I’ve seen firsthand how helpful the low FODMAP diet can be for my IBS clients. In this post, I’ll explain the low FODMAP diet, what foods to eat and what not to eat, and how you can start feeling better today!

What is the Low FODMAP Diet: Key Takeaways

THE FODMAP DIET DEFINED—A low-FODMAP diet is a temporary elimination diet designed to help manage IBS by reducing fermentable short-chain carbohydrates that trigger digestive symptoms, including bloating, gas, diarrhea, and more.
FODMAP ACRONYM – FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, carbohydrates that are poorly absorbed in the small intestine
THREE PHASES OF THE FODMAP DIET – Elimination (reduce high-FODMAP foods), Reintroduction (systematically reintroduce foods), and Maintenance (personalized diet based on tolerance).
HIGH-FODMAP FOODS – These include onions, garlic, wheat, milk, certain fruits (apples, cherries), and legumes.
LOW-FODMAP FOODS—Some options include chicken, oats, rice, walnuts, carrots, blueberries, and lactose-free dairy.
PERSONALIZATION IS KEY—A low-FODMAP diet is not meant to be a long-term restrictive diet but a tool for identifying trigger foods and creating a sustainable eating plan.
GUIDANCE IS RECOMMENDED – Best followed under the supervision of a trained low FODMAP dietitian for proper implementation and nutritional balance.

What is the FODMAP Diet?

A FODMAP diet temporarily eliminates certain carbohydrates that are high in FODMAPs. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. That’s quite a mouthful, right?

In a nutshell, FODMAPs are short-chain carbohydrates and sugar alcohols that are poorly digested or absorbed in the digestive tract. As a result, water gets pulled into the small intestine, leading to diarrhea and fermentation in the large intestine, which causes gas and bloating. Other common IBS symptoms include abdominal pain, cramping, and constipation.

The low-FODMAP diet, developed and studied by researchers at Monash University in Australia, has provided symptom relief in up to 75% of IBS patients who try it. (1)

Text graphic listing what FODMAP stands for.

Should I Try a low-FODMAP diet?

If you have been diagnosed with IBS and your physician has suggested you try a low FODMAP diet, then yes, you should! Most of my clients with irritable bowel syndrome feel significantly better after following a low FODMAP diet.

Important! Please consult with your physician or qualified healthcare provider before starting a low FODMAP or another elimination diet, especially if you have/have had an eating disorder, have undesired weight loss, or are pregnant or nursing.

High-fodmap foods

Review this shortlist of high-fodmap foods you will temporarily take out of your diet.

Certain dairy products, including milk and ice cream.
Some vegetables and fruits include apples, Brussels sprouts, cauliflower, cherries, garlic, onions, peaches, and more.
Most beans and legumes.
Some nuts, including cashews and pistachio nuts.
Certain sweeteners like honey, agave, and high-fructose corn syrup.

What can I eat on a Low FODMAP diet?

Although a low-FODMAPS diet may seem restrictive at first, there is still a wide variety of low-FODMAPS foods from all food groups that you can eat.

Mason jar salad with lentils, tomato, lettuce, tofu, and pumpkin seeds.

Here’s a short list of low-FODMAP foods

Fruit: Most berries, citrus fruit & melon, grapes, kiwi, & more.
Vegetables: bell peppers, cabbage, carrots, cucumber, leafy greens, lettuce, potatoes, tomatoes, and more.
Grains: Corn, oats, quinoa, rice, & more.
Nuts/Seeds: Almonds, chia seeds, pecans, pumpkin seeds, walnuts, & more.
Legumes: Peanuts, firm tofu, and canned/rinsed/drained garbanzo beans and lentils.
Dairy: Hard cheeses, lactose-free milk, lactose-free yogurt, & more.
Herbs & Spices: Almost all. Read More: Spice It Up! 70+ Ways to Flavor Your Low FODMAP Diet.
Eggs/Fish/Meat/Oils: All since FODMAPs are only found in carbohydrate-containing foods.

If you’ve visited other websites and noticed a discrepancy between high/low FODMAP food lists, this is likely because foods are continuously being tested and updated for FODMAP content. For the most complete and up-to-date list, I highly recommend The Monash University Low FODMAP Diet App.

FAQs About the Low FODMAP Diet

I get this question a lot, and the answer is no. You will avoid wheat, rye, and barley during the elimination phase of the low FODMAP diet because they are high in fructans, a carbohydrate, as opposed to gluten, which is a protein.

Suppose you haven’t been diagnosed with celiac disease or don’t have gluten sensitivity. In that case, you may still be able to consume other gluten-containing foods during the elimination phase, including soy sauce and regular (not labeled gluten-free or certified gluten-free) oats.

Additionally, when you start the reintroduction/challenge phase of the diet, you may find you can tolerate wheat or small amounts of wheat, barley, rye, and other grains with fructans in them, but only if you do not need to be on a strict, life long, gluten-free diet.

Most of my clients start feeling a little better on a low FODMAP diet within two weeks, but some take longer. In general, you should expect to see significant symptom relief on a low FODMAP diet within 4-6 weeks.

No. You shouldn’t follow a strict low FODMAP diet long-term. In general, you should start reintroducing higher FODMAP foods after 4-6 weeks on the elimination phase of the Low FODMAP Diet.

Because many high FODMAP foods are rich in dietary fiber and prebiotics that support good bacteria in the gut and a healthy gut microbiome, you’ll want to resume eating as many of these foods as possible. In addition, although a well-planned low FODMAP diet supports overall health, nutritional deficiencies can occur if the diet is followed long-term.

Because of this, your long-term goal should be to add back in as many higher FODMAP foods as tolerated. And, because your quality of life is equally important, you should be able to enjoy many of your favorite foods again, albeit perhaps in smaller amounts.

Because the reintroduction or “challenge” phase of the Low FODMAP diet can be more challenging to follow, I highly recommend you consult with a registered dietitian nutritionist or another qualified healthcare provider to help you with this phase. I would LOVE to work with you!

If you’ve tried following a strict low FODMAP diet for at least 4-6 weeks and haven’t noticed any improvement, there are other steps you can take to get better.

First, make sure you have implemented these general IBS Diet and Nutrition Tips.

Next, while this post doesn’t serve as medical advice, there are some common reasons you might not be getting better on a strict low FODMAP diet. These medical conditions include celiac disease, inflammatory bowel disease, endometriosis, SIBO, sucrase-isomaltase deficiency, histamine intolerance, other food sensitivities, and more.

Phases of the low FODMAP diet

Elimination. The first step is to follow a low-FODMAP elimination diet for 2-6 weeks. Most of my clients take ~ 4 weeks to complete the elimination phase.
Reintroduction. After you’ve been on a low FODMAP diet for four weeks and are (hopefully!) starting to feel better, it’s essential to try and start reintroducing higher FODMAP foods into your diet. In my experience, moving slowly through the reintroduction phase of the FODMAP diet is imperative. If you rush through this phase, you may find it very difficult to determine your personal FODMAP tolerance.
Personalization. I LOVE working with my clients on this phase of the FODMAP diet as we focus on long-term gut and overall health that keeps you energized, well-nourished, and feeling great!

Ready to get started on a low FODMAP diet?

I would LOVE to work with you, whichever stage of the FODMAP diet you’re on! And, because I realize everyone is at a different place when it comes to their health, I offer a few different ways we can work together.

Individual Nutrition Coaching. Work with me virtually, via video or phone.Although coaching sessions are customized to your needs, most clients work with me for 3-4 consultations over a period of ~ 3 months. In San Diego & want to meet in person? Let’s pick a spot to meet and work together!
The Complete IBS Diet & Lifestyle Toolkit. I’m excited to announce the launch of my new DIY IBS toolkit that gives you all the tools I use with my private coaching clients to help you heal your gut, optimize your health, and LOVE food again!
More IBS & Low FODMAP Resources. Please check out my IBS Resources Page for all my low FODMAP resources, including low FODMAP recipes, low FODMAP meal plans, and more!