FODMAPs may sound like a bit of a mouthful, but it's worth taking the time to understand how these fermentable carbohydrates impact your digestive system. Individuals who suffer from irritable bowel syndrome (IBS) frequently find that eliminating high-FODMAP foods
from their diets can seriously reduce unpleasant symptoms such as:
- Abdominal pain
However, in order to optimize your digestive health, you also need to fill your diet with high-fiber foods. This keeps your intestines happy and healthy, and helps address many of the same signs of dysfunction listed above.
The problem is, many high-fiber foods are also high-FODMAP. This can make it tricky to eat enough fiber-rich foods while sticking to the low-FODMAP diet. Read on to learn more about the science behind the low-FODMAP diet, how cutting out high-FODMAP foods can alleviate IBS symptoms, and a clear explanation of how fiber affects digestive health. Plus, the essential lineup of high-fiber, low-FODMAP foods to add to your shopping list.
What Are FODMAPs?
The acronym FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, And Polyols. These multisyllabic terms refer to four different types of short-chain carbohydrates and sugar alcohols that the digestive tract sometimes struggles to break down and absorb.
Many foods, including ones that are quite nutrient dense, naturally contain FODMAPs, including: vegetables (fructose), fruits (fructose), legumes (galactans), grains (fructose), dairy (lactose). They can be found in processed foods in the form of additives—for example, artificial sweeteners often contain polyols.
The whole foods that contain FODMAPs can also be important sources of healthy bioactive compounds, like inulin and galactooligosaccharides (GOS), two prebiotics that nurture the good bacteria growing in your gut.
While some people can eat foods high in FODMAPs without experiencing any issues, individuals with functional gastrointestinal disorders (FGID) and IBS typically find that these foods trigger gastrointestinal distress. The presence of partially digested FODMAPs in the body can produce the digestive disturbances that plague people with these health conditions. FODMAPs can linger in the large intestine, absorbing water and generating carbon dioxide, hydrogen, and methane gas, which causes the bowels to swell uncomfortably and interfere with proper digestion.
5 Signs Your Body Cannot Properly Digest High-FODMAP Foods
If your body has difficulty handling FODMAPs, the result, as explained above, will be a buildup of fluid and gas in the intestines.
Some symptoms that indicate you could benefit from a low-FODMAP diet include:
- Abdominal distention and pain
- Feeling full after eating or drinking only a small amount
Following a low-FODMAP diet can eliminate these problems, but it can also be challenging to consume enough high-fiber foods while following that type of eating plan.
The Basics of the Low-FODMAP Diet
Researchers at Monash University in Melbourne, Australia developed the low-FODMAP diet to treat and prevent IBS symptoms. Extensive, ongoing research shared in a series of published, peer-reviewed papers from the scientists at Monash provide the FODMAPs content for hundreds of different foods. This data forms the foundation for the lists of foods to eat and foods to avoid on a low-FODMAP diet. The Monash team has found that following a low-FODMAP diet reduces IBS symptoms for three out of very four individuals.
It can be a bit challenging implementing this eating approach, so if you're interested in giving it a try, consider finding a dietician who can help you get started and ensure you're getting an adequate intake of key nutrients like fiber (more on that in a bit).
What Conditions Can a Low-FODMAP Diet Be Used to Treat?
When you avoid high-FODMAP foods—and the digestive disturbances linked to them—you give your gut a chance to heal and reset.
Studies support the use of a low-FODMAP diet to treat digestive disorders as well as other health conditions that may be linked to the presence of partially digested FODMAPs, such as:
- Migraines triggered by the consumption of certain foods
- Multiple sclerosis
- Rheumatoid arthritis
Common Low-FODMAP and High-FODMAP Foods
The Monash researchers have yet to offer a publicly accessible database of low- and high-FODMAP foods, resulting in contradiction between different lists and resources designed to introduce the low-FODMAP diet. The Monash University low-FODMAP diet app can be a good guide to the latest information on the FODMAP content of different foods, though it does not contain the raw data behind different categorizations.
If you believe you could benefit from a low-FODMAP diet, don't let concerns about discrepancies or inaccuracies dissuade you. Reducing your overall FODMAP intake, which even an out-of-date list should facilitate, will be sufficient for you to gauge whether you have a FODMAP intolerance.
The lists below provide examples of common low- and high-FODMAP foods, but should not be taken as a complete list. That said, here's a good starting point.
The following foods should be mainstays for anyone attempting a low-FODMAP diet. If quantities are listed, those should be treated as the maximum amount to be consumed in a serving.
- Vegetables: Look for alfalfa sprouts, bamboo shoots, bell peppers, bok choy, broccoli (1/2 cup), carrots, chives, collard greens, cucumber, eggplant, ginger, green beans, kale, lettuce, okra, olives, parsnips, potatoes, pumpkin, radishes, seaweed, spaghetti squash, spinach, sweet potato (1/2 cup), tomatoes, turnips, yam, and zucchini.
- Fruit: Fill up on bilberries, blueberries, cantaloupe, clementines, lingonberries, grapes, guava, honeydew melon, kiwis, lemons, limes, mandarins, nopales, oranges, papaya, pineapples, passionfruit, raspberries, strawberries, and tamarind.
- Dairy and eggs: Items you can indulge in include butter, brie, Camembert, cheddar, cottage cheese, eggs, feta cheese, goat's milk yogurt, Greek yogurt (small amounts), mozzarella, parmesan, ricotta (2 tablespoons), and some hard cheeses, which tend to have a lower lactose content.
- Non-dairy milks: Opt for almond milk, coconut milk, hemp milk, macadamia milk, rice milk (200 milliliters) or soy milk.
- Red meat and poultry: Good choices include beef, chicken, lamb, pork, prosciutto, and turkey.
- Fish and seafood: You can't go wrong with cod, crab, haddock, lobster, mussels, oysters, prawns, salmon, shrimp, trout, or tuna.
- Plant-based meat products: Options such as tempeh, tofu, and corn all get the okay.
- Cereals and grains: Many here fit the bill, like bulgur (1/4 cup cooked), buckwheat, brown rice, corn flakes (1/2 cup), maize, millet, oat bran, oatmeal (1/2 cup), polenta, popcorn, potato flour, quinoa, rice, rice bran, sorghum, or spelt.
- Nuts and seeds: Snack on some almonds (15 nuts), Brazil nuts, chia seeds, flaxseeds (1 tablespoon), hazelnuts (15 nuts), hemp seeds, macadamia nuts, peanuts, pecans (15 nuts), pine nuts (15 nuts), pumpkin seeds, sesame seeds, sunflower seeds, or walnuts (15 nuts).
- Beverages: Drink up black tea (weak), beer (1 serving), coffee, fresh-squeezed fruit juice (125 milliliters from low-FODMAP fruits), gin, green tea, herbal tea, kvass, vodka, whiskey, white tea, water, wine (1 drink).
Individuals with IBS or SIBO, or who are simply interested in seeing how eliminating FODMAPs might improve their health, should avoid the following foods.
- Vegetables: Completely avoid alliums like onions and garlic (as well as products made from them like salts and powders) if possible, and eliminate or cut back on artichokes, asparagus, cauliflower, celery, leeks, mushrooms, shallots, snow peas, and taro.
- Fruits: Potential instigators of problems include apples, apricots, bananas, blackberries, boysenberries, cherries, currants, dates, figs, goji berries, grapefruit, lychee, mangoes, nectarines, peaches, pears, persimmons, plums, pomegranates, prunes, raisins, and watermelon.
- Dairy: Give buttermilk, cow's milk yogurt, cream cheese, custard, gelato, halloumi, ice cream, kefir, milk, and sour cream wide berth.
- Meat: Stay away from brautwurst, chorizo, and other sausages.
- Legumes: Limit your intake of black-eyed peas, broad beans, butter beans, kidney beans, lima beans, mung beans, soy beans, split peas.
- Cereals and grains: Look for alternatives to amaranth, barley, couscous, einkorn, freekah, rye, semolina, wheat flour, and wheat germ, as well as products made from wheat flour, including bread, cake, cookies, pasta, pastries, and so on.
- Nuts and seeds: Steer clear of almond meal, cashews, chestnut flour, and pistachios.
- Sweeteners: Check labels for agave, high-fructose corn syrup, honey, inulin, isomalt, malitol, mannitol, molasses, sorbitol, xylitol.
- Beverages: Don't quench your thirst with coconut water, kombucha, oolong tea, rum, soda, and sports drinks.
Should You Try a FODMAP Elimination Diet?
The basis of the FODMAP elimination diet is the elimination or restriction of foods and beverages with high FODMAP contents. The diet can be quite restrictive and should only be followed for short periods of time as it may not fully meet the body's nutritional needs.
It's important to note, too, that many of the foods eliminated by this dietary approach can be quite rich in nutrients, and should only be avoided by individuals whose symptoms could potentially be linked to issues with digesting FODMAPs.
For the duration of the diet—between 3 and 8 weeks—individuals avoid consuming foods that contain FODMAPs. Then, they reintroduce foods one at a time in order to assess whether a particular food or drink triggers symptoms. If it does, then they know to continue avoiding that item. If no symptoms occur after a week of ingesting a food or beverage on a regular basis, they can deem it safe to reintroduce to their diet going forward.
The Link Between Fiber and Digestive Health
So, how does all of this relate to fiber? Well, experts know that filling your diet with plenty of fiber—both soluble and insoluble—is an absolute requirement for good digestive function. When individuals fail to meet the recommended fiber intake guidelines, that can cause or worsen constipation, diarrhea, and symptoms of IBS and other digestive disorders.
The challenge for people whose guts don't like FODMAPs is that many foods high in fibers are also high in those pesky fermentable carbohydrates and sugar alcohols. This can make it very difficult to get enough fiber while following a low-FODMAP diet.
Before getting into how much fiber constitutes an adequate amount, let's go over the two different types of fiber.
What's the Difference Between Insoluble and Soluble Fiber?
As you may or may not know, there are two different types of fiber: insoluble fiber and soluble fiber.
Let's discuss insoluble fiber first. This type of fiber helps to bulk up stools, which can alleviate digestive issues such as constipation, diverticulitis, and hemorrhoids. Good dietary sources of insoluble fiber include brown rice, the skins of most fruits and vegetables, and the bran component of whole grains.
It's common for doctors to recommend increasing insoluble fiber intake to patients struggling with those symptoms, often through the use of an insoluble fiber supplement. Yet some researchers feel that recommendation should be reevaluated.
According to an article published in The Lancet, follow-ups conducted with 100 consecutive patients indicated that supplementing with bran, a type of insoluble fiber, only led to improvements in 10% of all cases. Even more concerning, more than half the patients (55%) felt that bran actually made their symptoms worse. The authors strongly suggest the use of other forms of fiber instead.
A randomized, placebo-controlled trial (the most rigorous kind of scientific study) published in The BMJ in 2009 compared the use of bran to psyllium, a type of soluble fiber. After 3 months of treatment, patients who took psyllium reported a 90-point decrease in the severity of their symptoms compared to a 49-point decrease for those who took bran. Plus, a significant number of participants in the bran group dropped out of the study early because their IBS symptoms worsened.
That brings us to soluble fiber, which functions like a sponge, absorbing liquid as it travels through the intestines. This can make stools softer and ease their transit. It also functions as a prebiotic, providing the good bacteria in the gut with the raw materials that fuel their growth. An adequate intake of soluble fiber can regulate the rate of digestion and reduce the frequency of IBS episodes. That said, when gut bacteria consume types of soluble fiber with high FODMAP contents, like inulin, gas is produced that can make IBS symptoms worse. Good dietary sources of soluble fiber include vegetables, fruits, legumes, and oats.
How Much Fiber Do You Need Each Day?
To keep your digestive system running smoothly, you should eat foods that contain both soluble and insoluble fiber each day.
The 2015-2020 Dietary Guidelines for Americans lists fiber as a nutrient that many of us under-consume, typically due to a low intake of vegetables and fruits. It also provides recommended fiber intakes broken down by age and sex. Those numbers are determined based on the recommended caloric intake proposed for each group—in general, the FDA suggests that you eat 14 grams of fiber per 1,000 calories.
The recommended intakes for each group are as follows:
- Children between the ages of 1 and 3: 14 grams
- Girls between ages 4 and 8: 16.8 grams
- Boys between ages 4 and 8: 19.6 grams
- Girls between ages 9 and 13: 22.4 grams
- Boys between ages 9 and 13: 25.2 grams
- Girls between ages 14 and 18: 25.2 grams
- Boys between ages 14 and 18: 30.8 grams
- Women between ages 19 and 30: 28 grams
- Men between ages 19 and 30: 33.6 grams
- Women between ages 31 and 50: 25.2 grams
- Men between ages 31 and 50: 30.8 grams
- Women age 51 and older: 22.4 grams
- Men age 51 and older: 28 grams
In order for your body to properly utilize the fiber you take in, you need to keep yourself well-hydrated. A good goal is to drink between 4 and 6 glasses of water daily.
If you haven't been in the habit of eating lots of high-fiber foods, you'll want to increase your intake bit by bit to give your system time to adjust.
High-Fiber, Low-FODMAP Foods to Add to Your Shopping List
Some of these will probably be familiar to you; others may not be. Why not let your low-FODMAP diet become an opportunity to try new foods?
- Bean sprouts (2 grams per 1/2 cup cooked)
- Broccoli (2.5 grams per 1/2 cup cooked)
- Carrots (2 grams per 1/2 cup raw)
- Collard greens (5 grams per 1 cup cooked)
- Corn (1.5 grams per 1/4 cup boiled)
- Eggplant (1.5 grams per 1/2 cup cooked)
- Green beans (2 grams per 1/2 cup boiled)
- Kale (1.5 grams per 1/2 cup cooked)
- Potatoes (3.5 grams per 1 unpeeled and boiled)
- Turnips (2 grams per 1/2 cup)
- Blueberries (1.5 per 1/2 cup)
- Kiwi (5 grams per 2 small)
- Mandarin (3 grams per 2 small)
- Orange (3 grams per 1 whole)
- Passionfruit (5 grams per 2 fruit)
- Pineapple (2 grams per 1/2 cup)
- Raspberries (3.5 grams per 1/2 cup)
- Strawberries (2 grams per 1/2 cup)
Nuts and seeds
- Almonds (2 grams per 10 nuts)
- Chia seeds (10 grams per 2 tablespoons)
- Peanuts (2 grams per 32 nuts)
- Pine nuts (6 grams per 1 tablespoon)
- Walnuts (2 grams per 10 halves)
Cereals and grains
- Amaranth (6 grams per 1/4 cup)
- Brown rice (3 grams per 1 cup cooked)
- Oat bran (2 grams per 1 tablespoon)
- Quick-cook oats (2 grams per 1/4 cup uncooked)
- Quinoa (5 grams per 1 cup cooked)
Can You Eat a Low-FODMAP Diet and Take Fiber Supplements?
The short answer is, yes! But keep in mind that there's no one universally applicable rule for determining the best way to balance your body's fiber and FODMAP needs.
According to Dr. Jane Varney, a researcher at Monash University, fiber supplements made from sterculia tend to be well-tolerated by people who struggle to digest FODMAPs. Her rationale is that these supplements can be used to treat and prevent IBS symptoms like constipation without the kind of gas formation seen with other fiber supplements.
Registered dietitian Kate Scarlata, who specializes in the low-FODMAP diet, recommends avoiding fiber powders and using supplemental chia seeds instead.
Last but not least, and as touched on earlier, research supports the use of psyllium, a kind of soluble fiber that appears to dramatically reduce IBS symptoms.
If you choose to use a fiber supplement, follow the same tactic described for increasing your dietary intake: go slow. Make sure you provide your body with ample time to adjust.
And a note of caution for those exploring commercial fiber powders: avoid any products that contain high-FODMAP ingredients such as wheat bran, inulin, chicory root, or sorbitol.
Expert Advice on Balancing Concerns About Fiber and FODMAPs
To be completely up front, managing gut health by maintaining the right fiber intake while cutting out high-FODMAP foods requires careful planning. You'll need to grocery shop and meal plan with your fiber and FODMAP goals in mind.
Here's an overview of how experts like Varney recommend allocating fiber intake across food types:
- Vegetables and fruits: Shoot for a minimum of seven servings daily (ideally, five servings of low-FODMAP veggies and two servings of low-FODMAP fruits). Incorporate a range of vegetables like carrots, corn, green beans, and eggplant alongside fruits such as kiwis, oranges, raspberries, and strawberries.
- Legumes: Rinse well before eating, and stick to a small serving size. Two fiber-filled options with fairly low FODMAP contents are chickpeas (1/4 serving) and lentils (1/2 cup serving).
- Cereals and grains: Plan on eating between four and six servings from this category each day. Good options include brown rice, oats, and quinoa. When deciding between low-FODMAP breads and pastas, always go for the one with a higher fiber content listed on the label.
- Nuts and seeds: Chia seeds make a lovely addition to porridges and smoothies, while sunflower seeds or pumpkin seeds add fiber and crunch to salads.