Fiber on the Low-FODMAP Diet

Fiber on the Low-FODMAP Diet

As a Certified Nutritionist, I can tell you about the food you can eat while you are on the Elimination Phase of the low-FODMAP diet – and that you may consider consuming foods rich in fiber and low in FODMAPs instead of taking a fiber supplement. This way you may receive a more accurate reading on what’s causing your symptoms, as fiber supplements could be the culprit.

Do We Need Extra Fiber with Low Fodmap Diet?

Fiber is exclusively a plant nutrient and plants need fiber to stand up tall or keep their shape. And simply put, whenever we eat more plant-based foods, we increase our fiber! Eating low-FODMAP fruits, vegetables, nuts, and beans (green) will help to naturally increase fiber, as well as give us phytonutrients and antioxidants which have been said to prevent disease and keep your body working properly.

We have learned from our mothers that fiber is important to help keep things “moving” and it’s true – but only for some. The problem is that for people with digestive issues, sometimes fiber or too much, even from supplements can cause painful symptoms.  

Getting enough fiber could help prevent obesity, lower your risk of diabetes (helps control blood sugar levels) and heart disease (lower cholesterol levels) and help with constipation. Be wary of what you hear from the media, doctors, or The Whole Grains Council – like this statement “a high intake of cereal fiber (the fiber from grain foods) was associated with a 19% lower risk of death from all causes, and a 25-34% lower risk of disease-specific deaths”.

Good thing if you are following the low-FODMAP diet because you won’t need to rely on cereal fiber or any packaged food for that matter. Eating more veggies, fruits, nuts, seeds, and wheat-free foods are far more beneficial than eating the types of cereal and other grains that are most consumed and familiar to the general public and unfortunately don’t have the nutritional profile they once did.

If you have the need to feel FULL you can go for low-FODMAP (choose NON-GMO) carbs like these:

  • Quinoa which is low-FODMAP, a seed (not a grain) and it’s a complete protein.  1 cup cooked = 12 grams of dietary fiber!
  • Brown rice – 1 cup cooked = 3.5 grams of dietary fiber
  • Cooked oats (quick dry).  Stick to a 1/4 cup serving = 4 grams of dietary fiber
  • Polenta –  1 cup cooked = 7.3 grams of dietary fiber
  • Buckwheat Kernels – Stick to a 1/8 cup serving = 2.1 grams of dietary fiber
  • Flakes of Corn (gluten-free) – 3/4 cup = 4 grams of dietary fiber

I believe the most important step anyone can take is to drink plenty of water and eat foods high in vitamins and nutrients like fruits and veggies, lean proteins and healthy fats. And if you have IBS, make sure you have both raw and cooked veggies, as just consuming raw could trigger symptoms.

Soluble vs. Insoluble Fiber

Fruits and vegetables are the best ways to get your soluble (and insoluble) fiber. There are benefits to both soluble and insoluble fiber, but keep in mind, most HIGH FODMAP foods are made of soluble fiber.

Soluble fiber dissolves in water. It attracts water and forms a gel, which slows down digestion. The emptying of your stomach is delayed and soluble fiber makes you feel full.

Low-FODMAP examples of foods with soluble fiber are blueberries, oranges, eggplant, carrots, grapefruit (1/4 or less), potatoes; oatmeal (1/4 cup dry), oat bran, tofu, flax and sunflower seeds (2 tablespoons), canned chickpeas (1/4 cup – drained and rinsed) and canned lentils (1/2 cup -drained and rinsed).

Insoluble fibers do not dissolve in water and they pass through the gastrointestinal tract relatively intact and speed up the passage of food and waste through your gut. These are great for people with IBS-C (IBS with Constipation).  Insoluble fibers are considered beneficial fiber for the gut because of the laxative effect and they add bulk to the diet, helping prevent constipation.

Low-FODMAP examples of foods with insoluble fiber are: seeds (2 tablespoons), nuts (no cashews or pistachios), brown rice, zucchini, celery (1/4 stalk), broccoli (1/2 cup), cabbage (common), tomatoes, carrots, cucumbers, green beans, dark leafy vegetables, grapes, and potato skins.

What Types of Supplements May Help Constipation?

If you absolutely have to take a supplement look for those made with Psyllium husk. It has shown to be effective in treating constipation and IBS symptoms.  Patsy Catsos MS, RDN, LD, Medical Nutrition Therapist, and FODMAP expert says: “I tend to recommend those (fiber supplements) made of psyllium husk, starting with a very small serving and increasing slowly over time. Supplements made of cellulose are also worth trying since cellulose is not fermentable”. Citrucel is a good fiber supplement for the low-FODMAP diet because it is non-fermentable.

*I am not a fan of aspartame or maltodextrin (and other synthetic or processed ingredients in Citrucel) so even though it helps IBS, I’d just like to point out that it is not all-natural like organic whole psyllium husk.

Fiber Supplements HIGH in FODMAPs

If you have IBS or another FGID (functional gastrointestinal disorder) and are currently taking a fiber supplement, chances are it may be made with functional fibers like inulin or oligofructose.  These prebiotic ingredients can influence beneficial bacteria to grow and can improve immunity or gastrointestinal health for some, but for people like you and me, it could mean the train has stopped and is not leaving the station… Be aware of fiber supplements made with the following or any packaged food that boasts “High in Fiber” with these ingredients:

  • Inulin – mostly obtained from chicory root or Jerusalem artichokechicory root extract.  Inulin is a HIGH FODMAP.
  • Beet fiber, corn fiber, soy fiber, citrus fiber
  • Carrageenan is a water-soluble fiber found in certain types of seaweed.
  • Guar Gum guar seeds are dehusked, milled and screened to obtain the guar gum.  It is used as a thickener and a binder.  Side effects include increased gas production, diarrhea, and loose stools.  Don’t take/use guar gum if you have a condition that causes obstruction or narrowing of your esophagus or intestine.
    • Some of our fans of Fodmap Life and experts of IBS have said that carrageenan, guar gum and other gums such as acacia, xanthan (low-FODMAP per the FODMAP Friendly app), and locust bean have caused symptoms.  You’ll find these in non-dairy kinds of milk, snack bars, yogurts, and ice cream.  *These have not been analyzed for FODMAPs yet so please do not be confused, as they are not currently on the HIGH FODMAPs list.
  • Other functional fibers that you will find in foods are pectin, chitosan, cellulose, methylcellulose, beta-glucans, polydextrose, resistant dextrins, fructooligosaccharides (FOS) used as an alternative sweetener, and acacia fibers.
  • In the article “Functional Fibers — Research Shows They Provide Health Benefits Similar to Intact Fibers in Whole Foods” by Constance Brown-Riggs, she says that “research suggests that when added fibers, such as soluble corn fiber, polydextrose, and soluble fiber dextrin (also known as resistant dextrin), are added to foods, they can help consumers increase their fiber intake without concerns about GI distress and, at the same time, confer health benefits associated with naturally occurring intact fiber sources.”  **Patsy Catsos MS, RDN, LD recommends not consuming corn fiber while on the elimination phase of the low-FODMAP diet.

Some Low-FODMAP Fiber Sources:

  • Oranges, raspberries, ripe bananas.  Everything pictured above is low-FODMAP BUT the blackberries – just 5 are HIGH in FODMAPs
  • Corn, potatoes (with skin), carrots, spinach
  • Brown rice and brown rice products
  • Rice bran (2 tablespoons)
  • Oatmeal (1/2 cup cooked)
  • Oat bran (2 tablespoons)
  • Quinoa
  • Nuts and nut butters (one handful or 2 tablespoons–no cashews or pistachios)
  • Seeds and seed butters (one handful or 2 tablespoons)
  • Canned, drained, lentils (1/2 cup)
  • Chia seeds, whole or ground (2 tablespoons)
  • Tempeh (3 ounces)

Tips for Getting More Fiber

  • Eat whole low-FODMAP fruits instead of drinking fruit juices (high in FODMAPs).
  • Replace white rice with brown rice products whenever possible
  • When buying gluten-free cereal keep in mind many options are low in fiber, so be sure you have a serving of low-FODMAP fruits with your cereal
  • When you’re bored at work, running around with the kids or on the go, snack on low-FODMAP veggies like carrots. 1 large carrot has 2 grams of dietary fiber.

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