Does fiber make you poop? Or can too much fiber cause constipation? Fiber is fantastic for your health, including your gut health, and it relates a lot to your poop! There can be some potential digestive concerns, though, so as a registered dietitian I'm sharing everything you need to know about fiber and poop and my best tips below.
Fiber: What it Is & Why You Need It
Fiber is a type of undigestible carbohydrate in plants. Because it is undigestible and has some unique properties (like it's fermentable!), fiber is associated with a variety of health benefits, like a decreased risk of:
For more information on the health benefits of fiber and foods that contain fiber, see my High Fiber Foods Chart article (with a free printable!)
Fiber for Digestion
Related to gut health is how fiber can aid digestion. The two different types of fiber, soluble and insoluble, aid digestion in different ways:
- Soluble fiber attracts water*, creating a gel-like substance with food during digestion. This then slows digestion, leading to potential benefits like weight regulation (the fiber helps you feel full faster), lowered LDL cholesterol and heart disease risk, and improved blood sugar regulation. (*This is why you want to drink plenty of water when consuming a high fiber diet!)
- Insoluble fiber, on the other hand, adds bulk to your stool and helps food pass more quickly through your stomach and intestines. This type of fiber may help prevent colon cancer and some gastrointestinal conditions (like diverticulitis).
And while this primarily happens with soluble fiber, both forms of fiber ferment by bacteria in your gut. This helps increase more bacteria in your gut, which also helps with digestion (and overall health).
Does Fiber Make You Poop?
Because of the ways both insoluble and soluble dietary fiber aid with digestion, fiber does indeed make you poop. Dietary fiber increases the size and weight of your stool, softens your stool, and adds bulk to your stool - all of which make it easier to pass.
In fact, fiber can be so helpful that it's often recommended as an intervention in patients struggling with constipation! One study found that dietary fiber noticeably increases stool frequency in constipated patients.
Can Too Much Fiber Cause Diarrhea?
But can you have too much of a good thing?
Fiber is beneficial for your health, but one potential sign of too much fiber is diarrhea.
One study found that fiber can worsen bloating, gassiness, constipation, and diarrhea in individuals with functional gastrointestinal disorders.
Does Fiber Make You Gassy?
Fiber can make you gassy, especially if you've recently started consuming a lot more fiber, or if you have any gastrointestinal disorders.
For example, in individuals with irritable bowel syndrome (IBS), due to their nature of being slowly fermenting carbohydrates, fiber can lead to bloating and gas.
Can Too Much Fiber Cause Constipation?
Fiber is often used to help relieve constipation, but consuming too much fiber too quickly may lead to some temporary constipation.
One study also found certain fibers may be constipating for some (wheat dextrin and fine/ smooth insoluble wheat bran particles) - but a lot more research needs to be done.
Check out another article to learn more about other symptoms of too much fiber!
Tips to Help Your Digestive System Adapt to More Fiber
If you find yourself experiencing any uncomfortable symptoms of too much fiber (gassiness, bloating, constipation, diarrhea), you may need to take a step back.
Try helping your digestive system more easily adapt to more fiber by trying to:
- Gradually increase your fiber intake over a few weeks.
- Drink plenty of water.
- Pause use of fiber supplements (and talk to your doctor before resuming).
- Check foods for fiber additives (i.e. inulin, chicory root extract) and consider holding off until you increase your fiber tolerance.
- Move your body (walking counts!).
For more information, head over to my article on Too Much Fiber? (and What to Do About it).
And of course, it may be warranted to work with a gastroenterologist if your gastrointestinal symptoms are not improving.
So, does fiber make you poop? It sure does! Fiber has a lot of unique properties that provide a lot of health benefits, including aiding with digestion.
That said, there can be too much of a good thing. Particularly in folks with gastrointestinal disorders or in those trying to increase their fiber intake too quickly, you make experience uncomfortable symptoms such as gassiness, bloating, constipation, and diarrhea.
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