What is the low FODMAP diet?

May 25, 2024

Written by Maeve Ginsberg

Medically reviewed by Rita Faycurry, RD

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Key Points

  • The low FODMAP diet is a special elimination diet designed for people with IBS, SIBO, and other gut disorders.
  • FODMAPs are a group of foods that can produce excess gas and cause gastrointestinal discomfort.
  • The low FODMAP diet can provide some relief for IBS symptoms and should be administered by a registered dietitian.

When it comes to IBS or SIBO, diet plays a critical role. Elimination diets are commonly prescribed to find irritating foods to remove from your diet for some period of time to find symptom relief.

Sometimes mistakenly called the "fob diet," the low FODMAP diet is a common elimination diet for people with IBS symptoms. It revolves around a group of fermentable carbohydrates that commonly cause gut discomfort for those with IBS, SIBO, and other gut health disorders.

What are FODMAPs?

FODMAPs fermentable oligosaccharides, disaccharides, monosaccharides and polyols. These are fermentable carbohydrates that include fructans, lactose, fructose, sorbitol, mannitol, and GOS. Here are some high FODMAP foods by FODMAP group:

  • Oligosaccharides: wheat, rye, onions, garlic and legumes/pulses
  • Disaccharides: dairy products like milk, soft cheeses, and yogurt
  • Monosaccharides: honey, apples, high fructose corn syrups, etc.
  • Polyols: found in some fruit and vegetables, as well as artificial sweeteners

As you can see, FODMAPS are in plenty of healthy, nutritious foods. So it's not a matter of health. Plenty of people eat high FODMAP foods daily without any problems. These FODMAPS are used by gut bacteria, fermenting them in the digestion process.

However, for people with IBS, this fermentation is where things get uncomfortable. With irritable bowel syndrome, you can have a more sensitive gut and/or issues with gut motility (how fast contents move through the intestines). As such, the extra gas produced by fermentation can cause the intestinal wall to stretch and expand, leading to common IBS symptoms like bloating, excess gas, abdominal discomfort, and abnormal bowels.

The low FODMAP diet was designed by Monash University and is commonly prescribed to IBS, SIBO, and other gut issue patients. You can read more about it here.

What is the low FODMAP diet?

The low FODMAP diet is an elimination diet where you remove all high FODMAP foods and eat low FODMAP foods in moderation. FODMAPS exist in different amounts in different foods. For example, strawberries are lower in FODMAPS than blackberries and can be consumed in moderation, whereas blackberries should be avoided altogether (more on specific foods later!).

Foods without FODMAPs, such as proteins and fats, can be consumed without limitation. Most produce needs to be limited, but you should continue eating fruits and vegetables! Milk can be substituted with lactose-free milk, and so on.

The low FODMAP diet is a complicated, highly restrictive diet that should only be followed under the supervision of a registered dietitian. You should not start the diet on your own without the guidance of a professional.

Your RD will teach you about the diet, which foods to eat, which to limit and avoid, and how to conitnue finding satisfaction in your meals with these restrictions in place. They will answer any questions and concerns you have so that you feel confident in following these new guidelines.

After a few weeks, if the diet works, you should experience a reduction in IBS symptoms. Your gas, bloating, and bowel movements should all improvement.

After 2-6 weeks following the full restrictions, you will gradually reintroduce each FODMAP group to test if a certain one aggravates your symptoms. This means you continue following all limitations of the diet except for one group. Your RD will help create a schedule to test each group and you will record any symptoms and reactions so that you can figure out which FODMAPs irritate you most.

The low FODMAP diet is not designed to be followed forever. Instead, it is an elimination diet used to determine dietary aggravants in order to improve IBS, SIBO, or similar symptoms. You will not have to eat this way forever!

Find a gut health dietitian here.

Trying the low FODMAP diet for IBS

Here are some food substitution ideas for the low FODMAP diet:

Fruits and vegetables all have some amount of FODMAPs, so be careful to check what quantity keeps them in the low FODMAP category. Here are some examples of fruits and vegetables you can eat in limited quantities:

Low FODMAP fruits:

  • unripe bananas
  • clementine
  • kiwi
  • limes
  • mandarins
  • oranges
  • papaya
  • passionfruit
  • pineapple
  • rhubarb
  • starfruit

Low FODMAP vegetables:

  • arugula
  • bean sprouts
  • bok choy
  • cabbage
  • carrot
  • choy sum
  • collard greens
  • cucumber
  • daikon radish
  • eggplant
  • green bell pepper
  • jicama
  • kale
  • lettuce
  • okra
  • tomato (cooked or canned)
  • spinach
  • yam

The Monash University FODMAP Diet app has a library of foods where you can check FODMAPs and see how much of each ingredient you can eat. Download it here.

Low FODMAP recipes

Your dietitian will likely provide you with some recipe ideas to keep your recipes delicious and nutritious. But here are a few low FODMAP recipe ideas for each meal:

Low FODMAP breakfast ideas

  • Lactose-free yogurt with gluten-free granola and a handful of strawberries
  • Overnight oats with raspberries
  • Frittata with spinach and Swiss cheese
  • Scrambled eggs with gluten-free toast or roasted potatoes

Low FODMAP lunch ideas

  • Salad with quinoa, carrots, bell peppers, chicken, and homemade dressing
  • Tuna salad lettuce cups
  • Pho soup
  • Turkey sandwich with gluten-free bread

Low FODMAP snack ideas

  • Energy balls made with oats, peanut butter, chia seeds, and (optional) protein powder
  • Hard-boiled eggs
  • Popcorn
  • Homemade gluten-free muffins

Low FODMAP dinner ideas

  • Roast chicken with sheet pan potatoes
  • Soy-glazed salmon with peppers and rice
  • Tofu or chicken curry
  • Tacos with corn tortillas

Find an IBS dietitian

As you can tell by now, navigating the world of FODMAPs is complicated. It can be hard to know which foods to eat in moderation and which high FODMAP foods need to be avoided altogether. Working with an experienced gut health dietitian is crucial to running the elimination diet successfully.

Fay Nutrition has plenty of board-certified RDs specializing in IBS, SIBO, and other gut health conditions who can help administer the low FODMAP diet and any other IBS treatment to help you find relief.

With Fay Nutrition, you can get matched with a dietitian in your area of concern covered by your health insurance, enabling you to pay as little as $10 per session.

Click here to get started.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.

  • Monash University - FODMAPs and Irritable Bowel Syndrome

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Maeve Ginsberg

Written by Maeve Ginsberg

Maeve Ginsberg is a health and wellness writer with a personal passion for fitness. As an ACE Certified Personal Trainer and former powerlifter, she loves combining her interests in health with her writing. Maeve has a Bachelor’s degree from Northwestern University. 

Rita Faycurry, RD

Medically Reviewed by Rita Faycurry, RD

Rita Faycurry, RD is a board-certified Registered Dietitian Nutritionist specializing in clinical nutrition for chronic conditions. Her approach to health is centered around the idea that the mind and body are intimately connected, and that true healing requires an evidence-based and integrative approach that addresses the root cause of disease. In her books and articles, Rita offers practical tips and insights on how to care for your body, mind, and spirit to achieve optimal health and wellness.