9 Ways to Incorporate Fiber while Following the Low FODMAP Diet
While the low FODMAP diet can be an extremely helpful way to identify dietary triggers and manage GI symptoms for those with conditions such as IBS, it is not uncommon for those following a low FODMAP diet to unknowingly reduce their fiber intake, especially when first starting out, since many high FODMAP foods that are temporarily restricted on the low FODMAP diet also happen to be fiber-filled. Below we compiled a few easy (and tasty!) ways to incorporate fiber into your diet while following the low FODMAP diet.
Why Should We Care About Fiber?
But first: What exactly is fiber, how much should we be eating and why is it so important for our health? Keep reading!
Fiber is an indigestible type of carbohydrate found in fruits, vegetables, nut/seeds, beans/legumes, and grains. It is currently recommended that men under age 50 consume at least 38 grams of fiber per day, and that women under age 50 consume at least 25 grams of fiber per day. Men over age 50 should aim for at least 30 grams daily, whereas women over age 50 should aim for at least 21 grams per day.
While one of fiber’s most widely recognized attributes is its ability to promote bowel regularity, it also plays a number of other beneficial roles like reducing our risk for developing certain cancers, helping us to feel full and stabilize blood sugar, and even helping to promote heart health by binding with some cholesterol in the intestine, causing it to then be excreted rather than absorbed. Further, our gut microbes, often referred to as the “gut microbiome,” rely on the fiber that we eat as their fuel source. In exchange for providing them with fiber from the foods that we eat, our gut bacteria produce beneficial compounds in return, called short chain fatty acids. These short chain fatty acids have anti-inflammatory properties and also serve as a fuel source for our colon cells to promote colon health.
One of the reasons why the low FODMAP diet is intended as a temporary elimination diet rather than a long-term solution is because indefinitely keeping foods out of our diet that are highly fermentable by gut bacteria may lead to fewer beneficial gut bacteria over time. By keeping up our fiber intake from low FODMAP sources while following the low FODMAP elimination phase, we can potentially help to prevent the loss of those good gut bugs. Additionally, we can continue to reap the other potential health benefits of fiber!
Fiber is typically divided into two main categories: soluble and insoluble. Soluble fiber absorbs water and forms a gel-like substance in the GI tract, slowing GI transit time and helping to promote more complete, formed bowel movements. It’s found in the fleshy parts of many fruits and vegetables, as well as oats, chia seeds, and in legumes and lentils. Conversely, insoluble fiber does not hold onto water and, instead, speeds up GI transit time. For this reason, insoluble fiber can be helpful for those experiencing constipation. It’s typically found in the skins of fruits and vegetables, nuts/seeds, and the outer portion of many grains. While both types of fiber are important (and most foods will contain a mixture of both soluble and insoluble fiber), those with IBS often find that soluble fiber’s bowel-regulating properties can be particularly helpful and oftentimes better tolerated than large portions of insoluble fiber.
Sources of Fiber to Consider
1. Suitable winter squash (~2-5 grams of fiber per ½ cup serving)
Now that it’s officially winter, a variety of delicious and fiber-rich winter squash are at the peak of their season and can make for a delicious, nutrient-dense addition to a variety of meals. To enjoy winter squash year-round, look for frozen cubed winter squash varieties in the frozen section of your grocery store. These can also be added to a smoothie for a thick, frozen texture. Canned pumpkin (in a 1/3 C serving), kabocha squash (also known as “Japanese pumpkin”), and spaghetti squash are all low FODMAP, and butternut squash is considered low FODMAP in a 1/3 cup portion. Try our Low FODMAP Spaghetti Squash Bowl, Pumpkin Pie Chia Pudding made with pumpkin puree, or simply add suitable roasted squash to grain bowls, salads, stir fries, pasta dishes, and more to up their nutritional value and fiber content. A few spoonfuls of pumpkin puree is also a delicious addition to oatmeal or plain, lactose-free yogurt—top with a drizzle of pure maple syrup and a sprinkle of pumpkin spice or cinnamon for added sweetness and flavor.
2. Low-FODMAP non-starchy vegetables (~2-5 grams of fiber per ½ cup cooked, or 1 cup raw)
There are still a number of high-fiber non-starchy vegetables that are suitable for the low FODMAP diet such as carrots, cucumbers, broccoli florets, eggplant, zucchini and yellow squash, tomatoes, radishes, green beans, red bell pepper, red cabbage, leafy greens (such as swiss chard, collard greens, spinach, baby kale, arugula, and romaine lettuce), fennel, and kohlrabi, just to name a few. Non-starchy vegetables are not a significant source of carbohydrates, but they do contain fiber and many health-promoting vitamins, minerals, and phytochemicals.
While these veggies can be enjoyed raw as part of a salad or on their own, some may find that eating large portions of raw vegetables can worsen their GI symptoms. If this is the case, cooking, blending, and/or pureeing these veggies may help you to tolerate them in larger portion sizes while still getting your fiber in. Try throwing a handful or two of spinach into your scrambled eggs, bulking up a pasta dish with some sautéed tomatoes or zucchini (in a suitable low FODMAP portion), or adding roasted eggplant and red bell pepper to a sandwich or panini on a low FODMAP bread of your choosing!
3. Potatoes with the skin (~4 grams of fiber per medium potato, 3 grams without the skin)
You may be surprised to learn that white potatoes, such as the Russet potato variety, actually contain a good amount of fiber! When you eat the skin in addition to the flesh, you’ll get an extra gram of fiber in along with some more micronutrients like potassium and many B vitamins. Sweet potatoes contain around the same amount of fiber as a white Russet potato and they are considered low FODMAP in a ½ cup serving (or about ½ of a medium-sized sweet potato). Potatoes are extremely versatile and can be mashed, baked, roasted, and even cooked in the microwave! For a quick, easy meal idea, try loading a baked potato with sautéed spinach and tomatoes, ¼ cup of canned chickpeas, and a sprinkle of pumpkin seeds, then top it off with a drizzle of garlic-infused olive oil. For a Southwestern variety, try stuffing the potato with sautéed chicken and red bell peppers, spices, cheddar cheese, and some low FODMAP salsa (hold the onion and garlic)—yum! You can even make sweet potato “toast” by slicing a baked (and cooled) sweet potato into ~4 slices, toasting them, and then adding your choice of toppings—peanut butter and strawberries, hard boiled eggs with a sprinkle of cheese, and more!
4. Low-FODMAP whole grains (~2-5 grams of fiber per ½ cup serving)
Some of the most fiber-filled whole grains out there also happen to be low FODMAP - quinoa, brown, wild, red, or black rice, and oats can all be used in both savory and sweet dishes for breakfast, lunch, or dinner. Try making a grain bowl by combining quinoa or a whole grain rice with your protein of choice (such as cooked chicken breast), non-starchy veggies (such as red bell pepper and broccoli florets), and a tasty dressing (we love using ~1 Tbsp tahini mixed with lemon juice or a suitable low FODMAP dressing). Additionally, oats can be used to make warm sweet or savory oatmeal For a grab-and-go option, overnight oats can come in handy, as well as suitable oat muffins for a tasty treat with some added fiber.
Other fiber-filled, low FODMAP whole grains include: millet, teff, sorghum, and buckwheat. While they may not be quite as common as oats, quinoa, or rice, try experimenting with adding a few handfuls to salads or tossing them into a grain bowl. Our gut microbes like diversity, so the more variety in your diet, the better!
5. Corn-based products (~2-4 grams per ¼ cup of polenta, ¼ cup of cornmeal, or 2 oz dry pasta)
Whole kernel corn and popcorn can be irritating for many, especially for those with IBS, since it is high in roughage, however, there are many corn-based products that are generally well tolerated and still have all of corn’s beneficial fiber. Polenta, cornmeal, and corn-based pastas are all great, easier-to-digest ways to reap the benefits of corn fiber. Serve polenta as you would another starch such as rice or potatoes and add any low FODMAP seasonings of your choosing. You can try a sprinkle of parmesan cheese along with spinach or tomatoes for added veggies and fiber! Cornmeal can be incorporated into baked goods to up their fiber content (and serve as a breadcrumb replacement), or used to make your own polenta or porridge. Many corn-based pastas are suitable for the low FODMAP diet and contain around 2-3 grams of fiber per serving.
6. Whole wheat slow-leavened sourdough bread (~2 grams of fiber per 1 slice of bread)
Despite the fact that it contains wheat, whole wheat slow-leavened sourdough bread is actually suitable for the low FODMAP. This is because the slow-leavening fermentation process consumes the majority of the fructans, which is the FODMAP that is found in wheat. The whole wheat sourdough variety is higher in fiber than sourdough bread made from refined wheat, since it contains all parts of the grain. This can be used for toast, sandwiches, homemade croutons, and more! Just make sure to check the label for other possible FODMAPs (such as honey, agave, onion/garlic, inulin, etc.)
7. Nuts and seeds (~2-4 grams of fiber per 2 Tbsp serving of most nuts/seeds, 10 grams of fiber per 2 Tbsp serving of chia seeds)
Sprinkle nuts and seeds into a salad, over lactose-free yogurt or oatmeal, or enjoy as a snack with a piece of low FODMAP fruit! Pumpkin seeds, sunflower seeds, sesame seeds, flaxseeds (stick to a 1 Tbsp serving), chia seeds, pine nuts, peanuts, walnuts, macadamia nuts and almonds (stick to a serving size of ~10 almonds) are all compliant with the low FODMAP diet and are a great way to increase the fiber content and nutrient-density of a meal or snack. You can even try roasting some pumpkin seeds for a crunchy, fiber-filled snack. Check out our recipe for Maple, Vanilla, and Pumpkin Spice Pumpkin Seeds here! Just note that cashews and pistachios are high FODMAP, so these varieties are not recommended while following the low FODMAP diet.
Chia seeds in particular are an excellent source of fiber, particularly soluble fiber. They can be added to smoothies, sprinkled into oatmeal or lactose-free yogurt, and can even serve as a binding agent in baked goods due to their ability to form a gel. Additionally, chia seeds can be used to make chia pudding for a fiber-filled breakfast, snack, or dessert.
8. Low-FODMAP fruit (~2-3 grams of fiber per serving)
Even though you may need to temporarily eliminate some familiar fruit options, there are so many varieties of fiber-rich fruit that you can enjoy while following the low FODMAP diet. Strawberries contain a whopping 3 grams of fiber per cup, while other low FODMAP fruits such as papaya, pineapple, clementine, cantaloupe, and kiwi contain around 2-2.5 grams of fiber per cup (or per 2 clementines or 2 kiwis without the skin). Papaya, raspberries (in a 1/3 cup portion) and oranges in particular are great sources of soluble fiber. Try pairing a piece of fruit with suitable crackers for a fiber-filled, sweet-and-salty snack!
9. Legumes/Lentils (2-8 grams per serving)
While most beans and legumes are off the table while following the low FODMAP diet, canned chickpeas in ¼ cup portions and canned lentils in ½ cup portions are considered low FODMAP and are significant fiber sources. ¼ cup of canned chickpeas contains just over 2 grams of fiber, while ½ a cup of canned lentils contains a whopping 8 grams of fiber. Since FODMAPs are water-soluble, be sure to drain the liquid from the chickpeas and lentils and then give them a good rinse to remove lingering FODMAPS that may have been sitting in the liquid. These are great for topping a salad or grain bowl, adding to soups and casseroles, or even for making dips like our Low FODMAP Hummus. Additionally, edamame is low FODMAP in a 1/2 C portion!
What is your favorite way to incorporate fiber while following the low FODMAP diet? Tell us below!
This post was written by Rachel Dyckman, RD, CDN