Insoluble Fiber | Good or Bad for Irritable Bowel Syndrome? Pause!

Does insoluble fiber help or hurt IBS? Both! It's a Catch-22, but hang on.

The IBS insoluble fiber contradiction can be solved fairly easily.

Insoluble fiber is the roughage fiber everyone is familiar with. Insoluble fiber is in bran, whole grains, raw fruits and vegetables, popcorn, leafy greens, sprouts, legumes, seeds, and nuts.

In short, the healthiest foods in the world are high in insoluble fiber, and what everyone should be eating as much of as possible. Right?

Well, right, except for one small problem.

The Problem with Insoluble Fiber

Insoluble fiber - like fat, the other big IBS diet trigger - is a very powerful GI tract stimulant. For those of us with IBS this spells big trouble.

Unlike fats, however, you cannot simply minimize your insoluble fiber foods. This would leave you with a seriously unhealthy diet.

One glance at the list below will tell you that insoluble fiber foods are the best and tastiest around. But your IBS just can't handle it if you eat them with abandon.

You absolutely must eat insoluble fiber foods, as many and as much as possible. But you need to eat them within the IBS diet guidelines.

Treat insoluble fiber foods with suitable caution, and you'll be able to enjoy a wide variety of them, in very healthy quantities, without problem.

Never eat insoluble fiber foods alone or on an empty stomach. Always eat them with larger quantities of soluble fiber foods. This will keep your gastrocolic reflex and bowel motility stable.

Here Are Your Insoluble Fiber Caution Foods

This is not a comprehensive list by any means but it should give you the general idea. In general, if a plant food is rough, stringy, has a tough skin, hull, peel, pod, pith, or seeds, be careful. This indicates insoluble fiber.

Whole wheat flour, whole wheat bread, whole wheat cereal
Wheat bran
Whole grains, whole grain breads, whole grain cereals
Granola
Meusli
Seeds
Nuts
Popcorn
Beans and lentils (mashed or pureed they're much safer)
Berries (blueberries, strawberries, blackberries, cranberries, etc.)
Grapes and raisins
Cherries
Pineapple
Peaches, nectarines, apricots, and pears with skins (peeled they're much safer)
Apples (peeled they're safe)
Rhubarb
Melons
Oranges, grapefruits, lemons, limes
Dates and prunes
Greens (spinach, lettuce, kale, mesclun, collards, arugala, watercress, etc.)
Whole peas, snow peas, snap peas, pea pods
Green beans
Kernel corn
Bell peppers (roasted and peeled they're safer)
Eggplant (peeled and seeded it's much safer)
Celery
Onions, shallots, leeks, scallions, garlic
Cabbage, bok choy, Brussels sprouts
Broccoli
Cauliflower
Tomatoes (peeled and seeded, especially raw, they're much safer)
Cucumbers (again, peel and seed them and they're much safer)
Sprouts (alfalfa, sunflower, radish, etc.)
Fresh herbs

To recap, you can help keep your gastrocolic reflex and bowel motility stable if you never eat insoluble fiber foods alone or on an empty stomach. Always eat them with larger quantities of soluble fiber foods. What does this mean in practical terms?

Cook some peeled diced vegetables into a low-fat sauce for pasta, stir-fry veggies into a fried rice, or blend fresh fruit into a smoothie to drink after a breakfast bowl of rice or oat cereal.

For fruits, vegetables, and legumes in general, you can break down the insoluble fiber before you even eat it. Just peeling, chopping, cooking, and/or blending them will significantly minimize the impact of their insoluble fiber on your gut. How can this be?

If you picture the difference between raw and cooked spinach leaves, or kernel corn versus cornmeal, it's easy to see how you could physically break down insoluble fiber before you eat it. That fiber is still present, it's not disappearing into another space-time dimension. But it will be much easier on your gut this way.

So make soups, drinks, sauces, breads, and dips from your veggies and fruits instead of eating them whole and raw.

For beans and lentils, cook and blend them into sauces, dips, soups, or spreads. The insoluble fiber is found in their outer skins and their insides are actually rich in soluble fiber.

For nuts, finely grind and incorporate them into breads or pastas for a safe soluble fiber base. For bran and whole grains, eat them in small quantities following soluble fiber foods.

For instance, have half a whole wheat dinner roll after a whole sourdough one, or mix a small amount of fat-free granola and berries into a larger bowl of rice cereal or oatmeal.

For raw fruit and green salads, eat them at the end of a soluble fiber meal instead of at the beginning when your gut is empty. For all insoluble fiber foods, start with small quantities and gradually increase your intake.

Some Fruits & Vegetables Are Particularly Troublesome for IBS

Sulfur-containing foods. Garlic, onions, leeks, broccoli, cauliflower, cabbage, asparagus, and Brussels sprouts. In addition to their high amounts of insoluble fiber, they produce significant gas in the GI tract and this can trigger attacks.

As with all other fruits and veggies, these are extremely nutritious foods with significant health benefits, so they need to be treated with caution but not eliminated from your diet.

Acidic foods. Citrus fruits, vinegars, and cooked tomatoes. Treat with extra care as well, as their acidity can cause both upper and lower GI distress.

Follow the rules for insoluble fiber and eat these foods in smaller quantities incorporated with soluble fiber foods. But please do eat them.

Fructose. A poorly digested fruit sugar, which can cause gas, bloating, and diarrhea. This is typically not true for sucrose, or plain table sugar. Honey contains fairly high amounts of fructose, but typical portion sizes of honey are quite small.

Fruit juices, particularly apple and grape juice, are often sky high in fructose and even more problematic than whole fresh fruit. It's much easier and faster to drink a large glass of juice and ingest a great deal of fructose than to eat an equivalent amount of whole fruit. So treat juices as you would insoluble fiber and drink them carefully, with soluble fiber foods.

Get a copy of the IBS insoluble fiber foods list with the diet cheat sheet below.

Understanding the difference betweeen soluble and insoluble fiber is critical for IBS. But there's another crucial factor as well. You will need to avoid the red light IBS trigger foods.


Take immediate control of your IBS symptoms with Heather's IBS diet kit...


Read on to learn all about your soluble fiber safe foods...