Low FODMAP diet for IBS: All you need to know

Irritable bowel syndrome (IBS) is a condition that affects your digestive system.

The American College of Gastroenterology estimates that 10–15% of adults in the United States experience IBS symptoms, while only 5% to 7% of adults have been diagnosed with the condition.

IBS can cause symptoms such as:

• diarrhea
• constipation
• bloating
• pain in your abdomen

The symptoms tend to come and go over time. In around 60% of IBS cases, eating certain foods can trigger symptoms. Healthcare professionals often recommend diet changes to help manage the condition.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) suggests that diet changes for IBS may include:

• eating more fiber
• avoiding gluten
• following a special diet called the low FODMAP diet

What is the low FODMAP diet?  

The low FODMAP diet is a way of eating that involves avoiding certain carbohydrates. These carbohydrates, called FODMAPs, can often be hard to digest and may make your IBS symptoms worse.

The term “FODMAP” stands for fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols. Each letter stands for a different type of carbohydrate that can be difficult to digest.

This diet involves limiting or avoiding foods that are high in FODMAPs for a period of time. You then gradually bring these foods back into your diet to see which specific foods trigger IBS symptoms.

On a low FODMAP diet, you may reduce or remove foods such as:

• Grains: wheat, rye, and barley
• Fruits: apple, apricot, blackberries, cherries, dates, grapefruit, mango, pear, and watermelon
• Vegetables: artichoke, asparagus, cauliflower, garlic, leeks, mushrooms (button or portabella), onion, and sugar snap peas
• Dairy products and dairy alternatives: coconut milk in a carton, frozen yogurt, ice cream, milk, soft cheese, soy milk, and yogurt
• Proteins: most beans and legumes
• Drinks: sodas and juices high in fructose, rum, and teas like chamomile, oolong, chia, and fennel

You will focus on eating low FODMAP foods such as:

• Grains: corn tortillas or chips, grits, gluten-free pasta or crackers, oatmeal, potatoes, popcorn, rice, sourdough bread, and quinoa
• Fruits: unripe bananas, grapes, kiwi fruit, lemon, lime, oranges, papaya, and pineapple
• Vegetables: bok choy, broccoli, carrots, chives, cucumber, eggplant, kale, lettuce, mushroom (oyster), olives, radish, and spinach
• Dairy products and dairy alternatives: almond milk or cheese, coconut yogurt, hemp milk, lactose-free ice cream, and cottage cheese
• Proteins: edamame, lentils, canned chickpeas, beef, chicken, eggs, fish, pork, turkey, tempeh, and firm tofu
• Drinks: most wine, beer, spirits, coffee, drinks sweetened with sucrose, tea (except chamomile, oolong, fennel, and chai), and water

If you have access to one, a registered dietitian can guide you through the low FODMAP diet and advise you on exactly which foods to eat and avoid.

Phases of the low FODMAP diet

The low FODMAP diet has three phases. These are:

1. Elimination

During this phase, you remove all or most high FODMAP foods from your diet. The American College of Gastroenterology advises that this phase should last between 2 and 4 weeks. Other sources in a 2020 research review suggest that the elimination phase can last up to 8 weeks.

2. Reintroduction

During the reintroduction phase, you slowly bring high FODMAP foods back into your diet. You will monitor your symptoms to see which foods might be affecting you.  

3. Personalization

Once you have learned which foods trigger symptoms, you may decide to avoid or reduce these foods in the long term. You can then bring the other high FODMAP foods that don’t cause symptoms back into your diet.

Benefits

The benefits of a low FODMAP diet in IBS can include:

• Reduced symptoms: Research from 2017 suggests that following a low FODMAP diet can improve IBS symptoms such as abdominal pain and bloating. The diet can also help to improve your quality of life.
• More effective than other diets: Evidence from 2020 suggests that the low FODMAP diet can be more effective than other diets used to manage the symptoms of IBS.
• Control over your life: Understanding what foods trigger your symptoms can help you to better manage your condition. You can then make food choices knowing that they won’t cause you discomfort.

Challenges

Some of the challenges of the low FODMAP diet could include:

• Nutritional deficiencies: If you try to follow the diet by yourself, without the support of a dietitian, you may not have a varied and balanced eating pattern. This may put you at risk of missing out on some important nutrients that your body needs.
• Hard to stick to and complex: A restrictive diet can be hard to stick to and follow for several weeks. The low FODMAP diet can also be complex when it comes to eliminating and reintroducing foods.
• Weight loss: Following a diet that is too restrictive may lead to unwanted weight loss.
• Constipation: Reducing the amount of FODMAPs in your diet may make you more constipated.  
• Cost: Research from 2018 suggests that following this diet in the long term can be more expensive than following a standard diet.

You can avoid several of these challenges by following the diet with the support of a registered dietitian, if you have access to one, or another healthcare professional.

Other IBS treatments

Your doctor may treat your IBS symptoms by recommending lifestyle changes, medications, probiotics, or mental health therapy. Other than changes to your diet, treatments for IBS include:

Medication

Medications may help with managing your IBS symptoms.

Medications like rifaximin (Xifaxan) and eluxadoline (Viberzi) can help with diarrhea. To treat constipation, your doctor may recommend laxatives or a medication like lubiprostone (Amitiza).

Other medications may be helpful for pain in your abdomen, such as antispasmodics like dicyclomine (Bentyl), antidepressants like sertraline (Zoloft), or peppermint oil capsules.

Probiotics

Probiotics introduce good bacteria into your gut. Research from 2022 suggests that probiotics can help with IBS symptoms. Your doctor can recommend a suitable probiotic.

Mental health therapy

Different types of mental health therapy can also help manage IBS symptoms:

• Cognitive behavioral therapy (CBT): This type of therapy helps you change your thoughts and behaviors so that you can feel better.
• Hypnotherapy: Hypnotherapy is a relaxation technique that may help manage the symptoms of IBS. Research from 2021 suggests that hypnotherapy focused on the gut can be a helpful treatment option for IBS.
• Relaxation techniques: Techniques to relax your muscles and manage stress, such as yoga and meditation, can help with your IBS symptoms, according to 2023 research.

A healthcare professional can help you to decide which treatment options are best for you.

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Summary

The low FODMAP diet can help manage IBS symptoms. 

The diet works by limiting certain foods from your diet that can irritate the gut. In the long term, the goal of the diet is to find out which foods may be triggering your IBS symptoms.

A healthcare professional or registered dietitian can guide you through the low FODMAP diet.

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