The Flat Facts On Fiber For A Flatter Tummy


I find that one of the best things about this blog is that we get to spend a ton of time online browsing the internet for things that you guys might find interesting. Most of the time what I end up writing about is something that I have personal experience with, but sometimes I actually end up learning completely new things while I’m researching.

Take today’s post for instance: Dietary fibers. Of course I knew that there were various types of dietary fiber, and common sense tells me that different types would have different benefits. What I didn’t realize was how many different types of dietary fiber there actually were. Certainly more than enough to make a decent blog post out of anyway!

In this article we’re going to talk about what exactly fiber is; how it’s classified, what benefits it can provide you with, and various ways you can work it into your diet. Regardless of whether you’re trying to lose weight or you’d just like to become a little more ‘regular’, you should definitely be able to take something away from this article that you can use.

What Exactly Is Fiber?

fiberWhen I hear the word fiber, the first thing I think about is bran muffins (which my grandparents used to eat on the regular when I was a kid). I ran a quick personal Facebook poll, and it turns out that I’m not alone in that though (although a lot of people also jumped to vegetables). Turns out, we’re all right – the term fiber actually refers to an exceptionally diverse group of carbohydrates that humans are incapable of digesting for the most part because we lack the digestive enzymes required to break them down.

Vegetables and other plants are the most common place that you’ll find fiber, but it can also be found in other places like nuts, seeds, and whole grains. In fact, there’s a good chance that if you’re eating well. you’re already getting fiber and you didn’t even know about it, because it’s classified in so many different ways (which we’ll get more into in just a little while).

The Absolute Fiber Guide - Types of Fiber and Health Benefits

How Much Of It Should You Be Getting?

The recommended daily intake of fiber for men is 38 grams per day. For women that number sits a little lower at 25 grams. If you’re eating a typical western diet full of processed junk (like most of the population does), you’re probably not even getting close to enough though – Most people are only getting 15-17 grams per day, which is about half of the RDA.


In 2001, fiber was officially classified into two main types – Dietary and functional (you’ll find all of the information on this in the first link I put in the post). The difference between the two is that dietary fiber is found naturally in foods, and functional fiber is added to food to give it more nutritional value (think things like white bread or cereal).

But here’s the thing – Knowing what kind of fiber it is doesn’t necessarily tell you anything about its nutritional value. After all, the average person only has a very basic knowledge of reading nutritional labels.

Dietitians and nutritionists have come up with a different method of classifying fibers that seems to be a little easier to understand. This is exactly the method I learned when I was working at the health store and it’s the only way I’d ever explain it to anyone else. Fiber can be classified by:

  • Solubility (soluble and insoluble).
  • Viscosity (viscous and non-viscous).
  • Fermentability (fermentable and non-fermentable).

But that’s just the beginning. Beyond those classes, there are others such as resistant starches (which are actually a lot better for you than they sound like they’re going to be) and other unique fibers. But with so many different classifications out there, how are you possibly supposed to know which is which and what kind of benefits or downfalls you could experience? Lucky for you, I’ve created a little breakdown to help you out:

Soluble & Insoluble Fiber

This is probably the easiest and most common way that you’ll see fiber classified. The solubility of fiber refers to its ability to be dissolved in water. Soluble fiber blends with the water in your gut to form a gel like substance that can reduce blood sugar spikes. Soluble fiber has been mentioned quite a bit here on e-health101 for its various metabolic health benefits.

You can find soluble fiber in a wide variety of places, here are a few of the more common sources:

  • fiber1Pectin.
  • Gums.
  • Beta-glucans.
  • Psyllium.

Insoluble fibers on the other hand don’t blend with the water in your gut and end up passing through your body mostly intact (aka they’re in pretty much the same shape when they come out as they were when they went in).

It mostly functions as a ‘bulking agent’ and might help your body get rid of food and other waste a little quicker than you otherwise would. Lignin and cellulose are two words you may have seen on a nutrition label or two at the grocery store; these are both insoluble fibers.

While you might get a little more of one or the other depending on what you’re eating, the fact of the matter is that there are various proportions of soluble and insoluble fibers in different plant foods. Working a wide array of different plant foods into your diet is the best way to ensure that you’re getting enough of both of them.

Viscous Fiber

You know that gel like substance that fiber forms when it’s soluble? Well, sometimes that gel is thick. When you hear someone referring to the viscosity of fiber, all they’re really talking about is how thick the substance is. For instance, honey is more vicious than water is.

Viscous fiber sits in the gut and slows down your digestion and absorption of nutrients. Because it takes you longer to digest a viscous fiber, you’re left with a sense of feeling fuller longer and might experience a reduced appetite. You might even feel like you have more energy.

A review was done on 44 different studies that were focused on fiber treatments; according to that review, only viscous fibers reduce food intake and cause weight loss. That means that if you’ve been having some issues getting that scale to climb back in numbers despite eating well and getting regular exercise, you might want to seriously consider working some viscous fiber into your diet.

Glucomannan, beta-glucan, guar gum, pectin, and psyllium are all great forms of viscous fiber, but if you’d prefer to get your sources from whole food sources as opposed to supplements, here’s a quick list of what you’re going to want to reach for:

  • fiber2Legumes.
  • Oats.
  • Flax seeds.
  • Brussel sprouts.
  • Asparagus.

Fermentable Fiber

It’s quickly becoming common knowledge that anything that’s fermentable is good for you because it helps up your gut health game. To give you an idea of just how important having good gut flora is, take a look at this – It’s so important that it’s actually been referred to in studies as the forgotten organ.

You see, there’s an estimated 100 trillion live bacteria in the average human gut (most of which hang out in the large intestine) that are absolutely crucial for our optimal health. The various bacteria play various roles in your system – From weight management to blood sugar control and even brain function and mental health, your good gut bacteria can either make or break you.

Because we’re unable to digest fiber, it ends up getting to out large intestine pretty much exactly how it was while we were chewing. However, when we ingest fermentable fiber our friendly gut bacteria are able to digest (ferment) it and turn it into fuel that we can use to get through the day. By eating fermentable fiber, the number of friendly gut bacteria in your system increases and reaches a better balance. That increase in balance in turn produces short0chain fatty acids that boast their own powerful health benefits.

Generally fermentable fibers come in the soluble form, but some insoluble fibers can function this way as well. Guar gum, beta-glucans, pectin, inulin, and oligofructose are all fermentable fibers that you can keep an eye out for on your nutritional label, and here’s a handy list of some whole food fermentable fibers that you should definitely consider working into your day to day life:

  • fiber3Beans.
  • Legumes.
  • Apples.

Beans and legumes are such incredible fermentable fibers that just a one cup serving often provides you with up to half of your RDA.

Of course, one of the side effects of fiber fermentation is gas (which you’ve probably had to suffer with at one time or another after a bowl of exceptionally good chili). You might experience some flatulence, cramping, and other discomfort when you first start ingesting fermentable fiber (especially if you don’t eat it on a regular basis), but that slight bit of short term discomfort is definitely worth it when you consider all that you’re getting in return!

Resistant Starch

Starches are how we get most of our carbohydrates (think rice, pasta, potatoes, etc.). Some starches are resistant to digestion, meaning that they make their way through your digestion system without changing much at all. This type of starch is referred to as a resistant starch; it acts like soluble, fermentable fiber in your gut (which we’ve already discovered is great for you) and thus boasts quite a number of health benefits. For example, resistant starches can improve your digestive health, increase your insulin sensitivity, lower your blood sugar levels, and might even significantly reduce your appetite.

Additionally, certain starchy foods like white potatoes and white rice tend to form large amount of resistant starch once they’ve cooled down from their initial cooking, so you might want to consider letting them cool down first if you want to reap all of the benefits they have to offer.

Raw potato starch is the most common thing used for resistant starch supplementation, but I just don’t see the point in supplementing something that’s so readily available! Here’s a list of foods that you can find dietary forms of resistant starch in:

  • Green bananas.
  • Bread.
  • fiber4Cereal.
  • Raw oats.
  • Cashews.
  • Chickpeas.
  • Beans
  • Legumes.

I could go on forever. Just click here if you’d like to view a full list.

Other Unique Fibers

So those are the most commonly referred to fiber, however they’re far from the end of it. Here’s a short rundown of other unique fibers; what their function is exactly and what foods you can get them from. I like to refer to them as ‘sub fibers’:


A fructan is the term that’s used to describe a small chain of fructose molecules. They can help feed the friendly bacteria in your gut and have even been shown to help treat certain types of diarrhea. That said, you should be aware they’re classified as FODMAPs. FODMAPs are types of carbohydrates that are known to cause digestive issues with certain people (think people with celiac). In fact, fructans and other FODMAPs can trigger adverse symptoms in 75% of people that suffer from conditions like IBS (irritable bowel syndrome).

Where to find them: Oligofructose and inulin are the two most common fructan varieties in the modern diet, and the most common whole food source is wheat.


Beta-glucans have a specific modular structure that makes them exceptionally viscous in the gut. Not only can they improve your insulin sensitivities and lower your blood sugar, they can also significantly reduce your cholesterol levels and increase feelings of fullness (which can come in really handy if you’re still feeling hungry even though you know you ate more than enough food).

Where to find them: There are a variety of sources that contain beta-glucan, but the two main and most accessible ones are oats and barley.


If you’re someone that frequents the weight loss supplement aisle at your local health food or grocery store, you may have seen glucomannan lining the shelves. In addition to helping with modest weight loss, studies have shown that this viscous fiber can help fight constipation and might even improve your risk factors for heart disease.


fiber5As you can see, there are a ton of different types of fibers (and sub-fibers) out there. So many in fact that the whole thing can seem a little overwhelming. Even this article only skims the surface when it comes to information (although if I do say so myself, it’s very well-researched and laid out) – How are you supposed to know that you’re getting enough? How will you know if it’s too much?

Answer: Just listen to your body. For the most part, it will respond positively to positive changes and negatively to negative ones. Even if you’ve had too much of a good thing, your body usually does a pretty good job of letting you know.

If you think that you’re having a bad reaction to any of these foods or if you’re worried about any other underlying health conditions, it’s never a bad idea to make an appointment with your health care professional – I’m not a doctor nor do I know you and your circumstances personally. This article is meant for informational purposes only; as always, I encourage you to continue doing your own research and come to your own conclusions.

The long and short of it is that good sources of healthy fibers can be found in vegetables, oats, legumes, nuts, fruits, dark chocolate, chia seeds, avocados, and other whole foods. I wouldn’t worry too much about making sure that you’re getting enough if you’re eating a diet that’s rich in whole foods though – Your dietary requirement should pretty much take care of itself at that point.

What sorts of foods do you eat on a daily basis to ensure that you’re getting enough fiber in your diet? Are you careful to make sure that you’re getting various kinds or do you pretty much just wing it? We always love hearing from our readers – Let us know about your personal experience in the comments section below.

Don’t forget to pin this article so that you can easily refer to it whenever you need a quick refresher on all the different types of fiber, and while you’re there you can follow us on Pinterest so that you can always make sure that you stay up to date with all of our fitness, diet, natural beauty, holistic living, and healthy eating news. Don’t have a Pinterest account yet and/or not planning on getting one? No problem! You can also find us on Facebook, Twitter,Google+ and Flipboard.