Fiber is great for your health—but can you get too much of a good thing?
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I regularly purchase a whole-grain wrap labeled “high-fiber.” While I’m sure I looked at the Nutrition Facts panel before initially buying it, I happened to glance at it again recently and was a little surprised—and maybe a tad concerned. One wrap contained 11 grams of dietary fiber. Some were from whole-grains, but the majority were thanks to extra fibers the manufacturer added. Most days this is a nice boost to get closer to recommended intakes, but what if you're consuming a wrap (or two) like this along with fruits, vegetables, legumes and whole grains. Is it possible to get too much fiber?  

What Is Fiber?

Fiber isn’t really flashy, exciting, or even controversial—especially in comparison to other nutrients like fat and sugar. Fiber does have consistency, though, when it comes to what research suggests about its health effects. Higher daily fiber intakes are associated with improved digestive health, decreased risk of digestive issues such as constipation, lower blood pressure, increased satiety following a meal, lower body weight, improved health of gut bacteria, as well as reduced risks of developing heart disease, type 2 diabetes, and certain cancers like colon, breast, and stomach. The problem is that the average daily intake is 17g for U.S. adults – an amount significantly below recommendations (listed below).

Even though intake is chronically low, it appears that more individuals are starting to look for fiber amounts on food labels like they might calories or sodium. But there's just one problem: food manufacturers are also aware of increased consumer interest in fiber, and over the last two decades, the practice of adding extra fibers (referred to as functional fibers) during processing has increased for the primary purpose of boosting the fiber amount on a food’s label. When it comes to my wrap with 11g of total fiber, I estimated that approximately 2 to 4g come from whole grains and the remaining 7 to 9g are probably functional fibers.

How Much Is Too Much?

Unlike the fibers naturally found in foods that are a blend of soluble and insoluble types, functional fibers are often one to two specific types of fiber that are added in bulk. While they can provide a nice boost, high intakes of functional fibers may be more likely to cause abdominal pain, gas, and bloating compared to naturally-occurring fibers.

There is no maximum intake for fiber—largely because of fiber’s positive health benefits. However, this was determined before the market had so many foods with functional fibers added. So, is this still true when you factor those in along with the fiber found in a healthy diet?

The answer appears to be “yes” but there is also evidence that one should proceed slowly and that the focus should be on getting fiber from foods that are naturally good sources first. Here are general guidelines for increasing and consuming fiber:

Get a Baseline

Track your fiber intake for a few days to get a baseline of your average intake. Don’t worry about other nutrients—just keep it simple with a daily running tally for fiber. I’m always surprised when I do this because my total grams are lower than what I assume.

Start with Food

Start by adding or substituting in foods with natural fiber like fruits, vegetables, beans, whole-grains, nuts, etc. Check out this overview of what foods are highest in fiber, as well as few foods high in fiber that may surprise you.

Consider Boosting Your Fiber Intake

Add in some occasional foods with functional fibers, or take fiber supplements as needed to boost intake. These fibers should be used to complement your food intake and not as a primary method to meet fiber needs.

Add Fiber Into Your Diet Gradually

Don’t go from 0 to 30g overnight. Gradually increase fiber to avoid discomfort and side effects. Try adding two extra servings of the foods mentioned above for a week. If tolerating well, then increase fiber-rich foods a little more.

Drink Lots of Water

Fiber acts like a sponge in the intestines, so water consumption needs to increase along with your fiber intake. This is true for both fibers naturally found in foods and those added during processing. If not, then you may experience some discomfort as that extra fiber tries to move through the intestines.