It’s all over the internet – FODMAP diets will cure your symptoms of irritable bowel syndrome (IBS)…. You can read scientific peer-reviewed journal articles, and you can find more reader-friendly pieces online. But, what is a FODMAP, how does it help, what foods are considered FODMAP, and does it actually make a difference? All of these questions and more are covered in this article.
What is a FODMAP?
FODMAP stands for “fermentable oligo-, di- and monosaccharides and polyols.” A chemical sounding description for certain classes of carbohydrates. But, wait! – not all carbohydrates are FODMAPs. These are short-chain carbohydrates, meaning their molecular structure only has one or two sugars and fewer carbons than long-chain carbohydrates.
Comprehensive tables are included in this article, but here are the basics:
- Fructose (fruits, honey, high fructose corn syrup, etc.)
- Lactose (dairy)
- Fructans (wheat, onion, garlic, inulin, etc.)
- Galactans (legumes such as beans, lentils, soybeans, etc.)
- Polyols (sweeteners containing xylitol, sorbitol, isomalt, mannitol, and stone fruits such as peaches, plums, avocados, cherries, and apricots)
How Do FODMAPs Affect GI Symptoms?
For some people, FODMAPs pass right through the gastrointestinal (GI) tract unchanged and without any problem. For others, FODMAPS are not easily absorbed in the GI tract, making them more likely to contribute to IBS symptoms such as abdominal discomfort and pain, distention, bloating, gas, and altered bowel habits (from diarrhea to constipation).
FODMAPs pull water into the GI tract to be absorbed. This process is called “osmosis,” which add to diarrhea, bloating and discomfort symptoms in IBS.
To complicate matters, if excess FODMAPs are eaten, they can be fermented upon by bacteria in the GI tract, producing extra gas in the process. No one with IBS needs additional fluid or gas in their GI tract.
Who Benefits from a Low FODMAP Diet?
IBS has been the most widely studied condition in relation to dietary FODMAPs. IBS can be a difficult condition to treat, as symptoms and triggers vary widely between individuals. For an easier absorptive load on the intestine, avoiding these foods may help decrease symptoms.
Research, however, is conflicting.
Some studies demonstrate improvement while others do not. It clearly works for an individual if they are avoiding FODMAPs and as a result experiencing less gas, less bloating, less stomach pain, and less diarrhea.
Low FODMAP diets have also been proposed with other GI diagnoses – inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn’s disease, and functional.
High and Low FODMAP Food Lists
From the ibsdiets.org website, these are the most comprehensive FODMAP food lists I could find. They may seem long and overwhelming, but when you have a question about a specific food, it is likely included on these lists.
Image credit: ibsdiets.org
So, now you know the details…. How do you actually follow this low FODMAP diet to see if it will work for you? First, remember that individual response and results vary greatly.
The first step is to eliminate all foods that are high in FODMAPs in your diet. This is called the “Elimination Phase” and should last for approximately 6 weeks. If you adhere to the diet perfectly, you will experience improvement in IBS symptoms.
At this point, the “Reintroduction Phase” begins.
Basically, you are reintroducing one food type into your diet, while still following the low FODMAP plan. You will need to keep a diary and note symptoms (presence or lack of) with each new food introduced. This methodology helps determine which foods are affecting you individually.
The recommended reintroduction schedule is as follows:
- Week 1 – Disaccharides – dairy foods such as milk and plain yogurt
- Week 2 – Polyols – avocados, blackberries, celery, cauliflower
- Week 3 – Oligosaccharides – canned black beans, almonds
- Week 4 – Fructans – wheat pasta, white bread
- Week 5 – Fructans – garlic, onion, leeks
- Week 6 – Fructans – dates, figs, grapefruit
- Week 7 – Monosaccharides – honey, mango, cherries
Sample Menu – Elimination Phase
Breakfast – 1/2c oatmeal, 1/2c strawberries, 1 T walnuts, cooked with water, 1 egg scrambled with spinach, coffee
Lunch – Grilled ham, cheese, tomato sandwich on gluten-free bread, Kale salad with cherry tomatoes & olive oil/lemon juice dressing, ice water
Dinner – Grilled salmon, quinoa sautéed with red peppers, pine nuts in garlic-infused olive oil, fresh orange, ice water
Sample Low-FODMAP Snacks
- Rice Chips, handful of cashews and a few baby carrots
- Chopped salad – tomato, cucumber, bell pepper, carrot, olives, vinagrette
- Vanilla lactose-free yogurt with strawberries and chia seeds
- Slushie – blenderized berries and ice
- Quesadilla with gluten-free tortilla & cheddar cheese
- Swiss cheese and nut crackers (gluten free) and an orange
- Rice cakes with almond butter and sliced banana
- Gluten-free cereal with almond milk
- Tahini (sesame seed paste) with carrot and bell pepper sticks
- Pumpkin seeds and low-sugar dried cranberries
- Gluten-free tortilla with almond butter and low-sugar jam, rolled up
- Cantaloupe slices wrapped in prosciutto
- Gluten-free potato chips
- Scrambled egg with chopped peppers and onions
- Smoothie – almond milk, almond butter, raspberries, crushed ice, chia seeds
- Plain air-popped popcorn
- Hard boiled egg with freshly ground pepper
- Gluten-free tortilla chips with salsa
- Rice crackers with sliced smoked turkey
- Sweet potato chips
- Tuna on gluten-free crackers
- gastrointestinal disorders (FGID), an all-encompassing term for a variety of nonspecific GI problems.
Starting a new low FODMAP diet can be overwhelming, and these cooking tips may help you navigate.
- Cooking methods do not generally reduce or change FODMAP content. Exceptions are canning and pickling processes. Some of the FODMAP will ‘leach’ out into the canning or pickling acidic fluid, especially in chickpeas and lentils. Therefore, the FODMAP content in canned chickpeas is lower than fresh chickpeas. Be sure to rinse the legumes well.
- Garlic and onion, very popular ingredients in cooking, are quite high in FODMAPs. Cooking the garlic and onion in oil helps to reduce the FODMAP content. So, go ahead and sauté these tasty seasonings with some oil allowing the flavors to infuse the oil. Then, discard the solids and use the delicious infused oil too cook with.
- Meal planning, batch cooking, and homemade freezer meal preparation will become your best friends. Many convenience foods contain FODMAPs, even commercially available broths. Planning a weekly menu, prepping foods at the beginning of the week, and using them throughout the week will save you time and stress. Cook up a large portion of quinoa or rice and use it in recipes throughout the week. Chop up the vegetables you need for the entire week at once to save time later in the week. Organizing your week will lead to greater success.
How Does FODMAP Relate to Gluten?
Are FODMAPs and gluten related? No, not at all.
Gluten is a protein found in wheat, barley and rye. Remember, FODMAPs are carbohydrate.
Some gluten containing grains are allowed on a low-FODMAP plan, therefore a low FODMAP diet is not necessarily gluten-free. Overlap of certain foods occurs in these two plans, but some gluten containing foods are allowed on the low FODMAP plan.
It is also important to remember that eliminating FODMAPs will, in turn, reduce the amount of gluten in the diet. Individuals with celiac disease or gluten intolerance, who need to avoid gluten will need to adjust the food lists below to meet that requirement.
- Gluten – protein
- FODMAP – carbohydrate
Nutrient Deficiencies in the Low FODMAP Diet
Because the low FODMAP diet is quite restrictive, it is inadequate in certain micronutrients (vitamins and minerals). If followed for a long period of time, supplementation may be needed. With omission of dairy and many fruits and vegetables from the diet, supplementing with calcium, vitamins D, A and C should be considered.
The low FODMAP diet is also low in fiber, and in vegetarians can also be deficient in protein. Consulting a Registered Dietitian specializing in GI diseases is highly recommended.
- Research on effects of the low FODMAP diet on IBS symptoms is promising.
- Utilizing the Elimination and Reintroduction Phases is ideal for determining individual tolerance and triggers.
- The low FODMAP diet can be very difficult to follow, but with organization and planning, it can be done successfully.
- Certain vitamins and minerals should be supplemented if the low FODMAP diet is adhered to for a long time period.
Dr. Jennifer Bowers is a Registered Dietitian with 25 years of experience in clinical nutrition and health promotion. Dr. Bowers earned her PhD in Nutritional Sciences from the University of Arizona.