“it is unequivocally the most painful experience I’ve ever gone through, more painful and debilitating than childbirth.”


For the last two months I have been recovering from some gastrointestinal (“GI”) issues which included among other things, a GI infection and inflammation. Because of this, I have been digesting (pardon the pun) as much information about the GI and good GI health as much as possible to try to understand my situation, the best path to recovery, and how best to prevent a relapse in the future.

One large topic which should come as no surprise, is the topic of fiber in our diet. Many people talk about the need for fiber in your diet, but few people talk about the consequences of not getting enough beyond the minor inconvenience of having to spend a little extra time on the porcelain throne. The quote above is not about the experience of having consuming more fiber unfortunately, but about what potentially happens when you don’t consume enough. It came from talking to a friend at growth group, who is a physician, recent mother, and someone who went through the same GI issues as I’m going through – and so there you have it, I’ve gone through something worse than childbirth! It’s good to have a point of reference.

Two things that struck me very quickly are:

  • All the issues that can arise from not getting enough fiber (who knew there were so many!), and
  • How “hard” it can be to get a sufficient amount of fiber in your diet if you’re not at least a little bit consciously about it

The former amazed me beyond how much the GI tract already amazes me as a microcosm of self-managing symbiotic microorganisms. It’s seriously mind-bogglingly cool what happens there! The latter astounded me in just thinking about the content of all the processed, or prepared foods that we so conveniently grab and go to keep ourselves going. If we think about it, our food usually consists of meats, carbs, and a scant smattering of veggies (potatoes don’t count!).

When thinking about your health, I like to think about it in terms of three areas:

  • Chemistry
  • Biology
  • Physics

This is a simple way to say that when you think about things that affect your health respectively there are substances, organisms, and the mechanisms of how your body function. With regards to fiber, we are for the most part touching squarely on the last of these: the mechanics, but of course as with all things of the body there’s still a little chemistry and biology involved all working in concert with each other!

Why fiber?

First and foremost, fiber is useful for helping your body digestion and the elimination of waste. The story, however, isn’t as simple as that because there are two primary types of fiber, and we have to treat these separately:

  • Soluble fiber, and
  • Insoluble fiber

These two types of fiber are not a substitutes for one another either – as I used to think they were – despite how similar they sound to each other. This is to say, fiber is not simply fiber. Both soluble and insoluble fiber are required for you to maintain the health of your digestive system, and you need a good balance of both.

By itself, fiber is that part of your food that your body doesn’t absorb directly. Fiber is required largely for three reasons:

  • It provides positive feedback for your body allowing you to feel more full, more quickly, and for longer
  • It adds bulk to your waste product making it easier for your body to eliminate waste, and
  • It helps with digestion and to clean your “pipes”

Generally speaking, fiber rich foods take longer to digest and add bulk to waste material. Consuming fiber is one of the ways that your body knows that it is full. The slower release of glucose to the bloodstream helps regulate food intake, prevents spikes in glucose (one cause of food coma), and also prevents you from getting hungrier faster.

PeristalsisNext, to understand why bulk is helpful, you have to remember back to your 6th grade biology class and recall how peristalsis works. As you can see to the right, it’s the sequential wave action of your body that’s caused by the coordinated contraction and relaxing of muscles in sequence – much like how an earthworm moves as it slinks along. In this case however, your body performs this action to move things along through your system – pretty simple, but pretty amazing if you think about how your body is able to reflexively perform this sort of coordination by itself. It is, in fact, amazing enough of a process that yes, sometimes it does break down which causes problems. In any case, having sufficient bulk gives your system something to push along rather than spending significant effort to move loose material through your system. Think of it this way. If you had to move loose sand vs sand in a box from one end of a table to another, which would be easier? In the same way, fiber acts as a structure which binds to food material and the subsequent waste, holds it together, bulks up, and allows you to move the material along more easily.

Finally, you can think about fiber as something kind of like an abrasive and scouring pads for your digestive tract. As waste product moves through your system, having fiber will trap smaller waste particles and drag them along as your body moves the material through your digestive tract. This prevents the buildup of waste within your system which can cause a myriad of long-term health issues. One indication of this happening is excessive bloating from gas. In some cases, this can add up to almost 2-3 inches to your waistline.

What exactly is fiber?

fiber-ropePersonally, in my imagination when I used to think about fiber, I used to think it was basically something like what you see to the right.  Most people think of fiber as all the indigestible portions of food derived from especially green plants (e.g. cellulose) like spinach, arugula, and Brussels sprouts. While this is grossly true, it’s not 100% accurate. Fiber is largely indigestible by us but it is processed in various ways by enzymes, bacteria, and other symbiotic microorganisms in our digestive system. After all, sharing is caring!

Soluble fiber is fiber that readily dissolves in water. This is NOT the fiber that you’re accustomed to thinking about since it mixes with water and becomes a solution, essentially disappearing from plain sight. Texturally, it forms almost a gel-like substance when dissolved in water and increases in volume. This is the type of fiber which controls blood sugar by slowing the release of glucose for absorption.

Insoluble fiber on the other hand, is roughage – in other words, eat your veggies! This IS the fiber you’re accustomed to thinking about, that which you abhorred eating as a child, and now pay an arm and a leg for right before drowning it in some wonderfully decadent, heart-stopping dressing. Trust me, go easy on the dressing. In any case, this is the type of fiber which prevents constipation.

Here’s a quick rundown of the differences between the two and touches on why we need it:

Soluble Insoluble
Dissolves readily in water Does not dissolve readily in water
Slows movement of foods through digestive system Accelerates movement of food through digestive system
Readily fermentable in colon Can be fermentable or inert
Examples: Pectin (e.g. the thickening component in jams), gums Examples: Cellulose
Sources: Oaks, beans, fruit Sources: Brans, greens, grains

Gas, Prebiotics, Your Immune System

Two of the things I alluded to is that fiber is something that is not digestible … by us, and also the microcosm of microbiology in our digestive system.  These two are related believe it or not, and this was another things that surprised me.

Firstly, if it’s not digestible by us, then who?  The fiber we consume is digestible by the bacteria and microorganisms in our intestines.  These specifically are good bacteria that live symbiotically with us and help us stay healthy.  Pretty cool, huh?

Certain types of fiber that we consume from specific sources are considered “prebiotic” (vs probiotic) because they provide nutrients that help the good bacteria that is already present in our bodies flourish.  The bacteria consume this prebiotic in a process which essentially the same as fermentation not unlike how yeast consumes sugar to produce alcohol and gas for beer.  This is why when you eat an excess of fiber, you produce some gas.  If you provide the nutrients the good bacteria in your gut needs to flourish, it can multiply, do more, and also crowd out the bad bacteria that may want to take up residence in your digestive system.  The gas production is normal, and good because it shows that your intestinal flora is flourishing and in good health.  A lack of gas can potentially be a bad thing, and an extreme excess of gas can also be bad as this could indicate other issues such as an excess of waste matter or bad bacteria flourishing.

Healthy intestinal flora is useful for plenty of reasons including improving digestion since the byproduct of the good bacteria (e.g. lactic acid) helps break down nutrients further which helps with our ability to absorb them.  Because the intestine is where most of our food, nutrients, or really anything is absorbed by our body (not the stomach as we conventionally believe), it’s important to have good intestinal health because toxins, and other infections organisms could also potentially enter our bodies from this avenue.  Other potential positive effects of good intestinal flora include providing an environment hostile for unwelcome microorganisms by changing and managing the pH levels in our intestines through to the colon, which may in turn help with the prevention with colorectal cancer.

So much goes on in our intestines that a lot of research is still ongoing to understand some or most of it, so what you see here is only a small tip of the iceberg.

One last note – most people confuse prebiotics with probiotics.  They are not the same, and they differ in that prebiotics are nutrients which help promote the growth of good bacteria already in your system.  Probiotics are actual bacterial cultures which are (potentially foreign – not previously existing in your system) being explicitly introduced.  One thing to keep in mind is that prebiotics may be more effective than probiotics because in order for probiotics to make it into its proper place in the small or large intestine, it needs to make it through the stomach and the accompanying acid bath which potentially kills most of them.  They still help, but it requires more effort and may not be as effective.  Maybe taking an antacid or a PPI prior to taking a probiotic may help, but talk to your doctor about specific concerns and strategies before attempting any sort of regiment.

Where do I get it and how much should I have?

fiber-foodsBefore getting into where the best places to get it, keep in mind that adding fiber to your diet can be a significant change to what your body is naturally used to. Your digestive system, like any other part of your body, is a muscle and it has to be acclimated to what it’s getting or you could encounter problems. What I mean to say is, if you suddenly, and very significantly increase your fiber intake, you could do more harm than good and cause all sorts of issues by stressing your system out with more than it can handle. Gradually increase your natural intake of fiber and you should be fine. If you have any doubts, talk to your doctor first.

Generally speaking, the rule of thumb is about 10-20g of fiber for every 1,000 calories of food you consume. I make this a point because on average, most people only consume about 15g of fiber a day. We need almost twice that – but again, don’t go rushing out there and loading up on fiber all in one shot. Work your way up to it. Here are the guidelines:

  • Women: ~25g/day
  • Men: ~38g/day

Getting more fiber doesn’t have to be painful, or artificial. Most people are used to seeing those horrible commercials for products that add fiber to your diet and have images of eating cardboard to make up this deficit. Below, you’ll find a list of the most fiberful foods, along with their respective contents of both soluble and insoluble fiber content. I took the liberty of filtering for the top four from each category. I’ll add more categories and foods over time but this should help you get started.

To help you along, I’ll also add delicious recipes for each one of these foods so you can have some ideas of how to increase your fiber intake without hating every minute of it. Some wonderful categories are noticeably missing (e.g. nuts) – I’ll get to it!

Food Serving size Total Fiber (grams) Soluble Fiber Insoluble Fiber
Brussels sprouts, cooked ½ cup 4.5 3 1.5
Artichoke, fresh ½ cup 4 3 1
Carrots, cooked ½ cup 2.5 1 1.4
Broccoli, cooked ½ cup 1.5 1 0.5
Apple 1 medium 4 1 3
Blackberries ½ cup 4 1 3
Pears 1 medium 4 2 2
Banana 1 medium 3 1 2
Lentils, cooked ½ cup 8 1 7
Pinto beans, cooked ½ cup 7 2 5
Lima beans, cooked ½ cup 6.5 3.5 3
Kidney beans, cooked ½ cup 6 3 3
Whole grain cereals
All Bran cereal 1/3 cup 8 0.7 7.3
Wheat germ 2/3 cup 8 1 7
Pearl barley, cooked ½ cup 5 2 3
Brown rice ½ cup 4 0.5 3.5
Psyllium seeds 1 tablespoon 6 5 1

** One thing to note – if you are increasing your fiber intake, also remember to increase your water intake!  For both forms of fiber, water is absorbed and needed to help keep things moving to prevent obstructions.  Drinking more water also helps manage and clear unwanted gas which will also come with the increased fiber intake.

What happens when you don’t get enough?

So now you know all the good stuff about why you need it and where you can get it.  “But”, you’re probably asking yourself “I feel fine, do I really need to manage my fiber intake?”  Well, that’s what I thought to myself before this episode as well.  To answer that question, here’s a quick rundown of all the things that could result from a deficiency of fiber in your diet and as promised, there’s more than I knew to expect and this is just a short list!

Short term:

  • Difficulties in digestion
  • Reduced ability to absorb nutrients
  • Elevated cholesterol
  • Hemorrhoids
  • Liver complications
  • IBS – Irritable bowel syndrome
  • Constipation
  • Increased susceptibility to illness – recall earlier discussion on fermentation and probiotics
  • Inflammation – due to unmanaged pH levels, build up of foreign matter,etc.


Long term:

  • Heart disease
  • Colon cancer
  • Diverticulitis – painful development of cysts and pockets in the intestinal lining which can trap waste matter and result in various complications potentially requiring surgery

I didn’t go into details about all of these potential consequences which are symptomatic of fiber deficiency, but you can Google for them and get a pretty comprehensive description of each of them as well as their relationship to a fiber deficient diet.


Pharmaceutical Substitute Remedies

For those of you who may be suffering from some conditions which may be causing some digestive issues like constipation, our natural inclination may be to visit the pharmacy. Consider, though, that mother nature may have an effective alternative before loading up on chemicals and compounds. These are some that I’ve found to be interesting and (yes, personally) effective remedies to the OTC pharmaceutical alternatives:

Function Natural Food Pharma Alternative Function Pharma Side-Effects
Bulking Agent Raspberries, Bran Metamucil, Benefiber Bulking agents add volume and promote the retention of water in stool to help your body’s natural peristaltic action move waste along. Cramping, bloating (gas), possible obstruction.
Lubricant Sunflower Seeds Mineral Oil, versions of Ex-Lax, Phillips, and Colace that contain Docusate. Lubricants typically function by adding a layer of mineral oil (liquid petrolatum) to your intestinal lining and stool which serves to help it retain water and lubricate the tract. Petroleum distillates in general are not good for the body. Prolonged use can also reduce the absorption of certain nutrients and vitamins including vitamin K, which promotes clotting, as well as other supplements. Mineral oil can also cause pneumonia if it leaks into the lungs (inhaled during oral administration)..
Stimulant Laxative Almonds Ex-Lax, Dulcolax Stimulants work by promoting the contraction of the intestinal walls. Dosing for stimulants is tricky and these are also the harshest of all the laxatives. Long term use is also an extremely bad thing as your body could develop a dependence and have a reduced ability to be able to trigger these actions itself. Overdosing can also cause injuries.


Well, there you have it.  A primer on the importance of fiber in your diet, all the benefits, and potential issues that can arise from not getting enough – after all, you don’t want to experience a pain greater than that of childbirth if you don’t have to … do you?  Hopefully it’ll be useful as you think about your nutrition and especially as you think about your day-to-day food choices.  And again, check back often as I’ll be updating some of the references with more information and also be adding recipes to the food list above over time.

Happy, healthy eating!


Print Friendly, PDF & Email

1 comment for “Fiber

Comments are closed.