Fiber: What is it and Why you need it

By Mike Howard

i-a2ba4204a99b85de5c8ce397a82e524c-db fiber.jpgLet’s talk roughage… Not the most exciting topic in the world but a very important piece of any dietary puzzle nonetheless. We’ve all heard about the importance of fiber when it comes to the gut, but here are some other factoids about fiber you may find interesting.

That, or you will click out of here to search for something more exciting – like trucking regulations.

  1. Fiber is the non-digestible part of a plant. It is broken into 2 categories – soluble and insoluble.
  2. Soluble fiber forms a gel when it comes in contact with water. Sources include; Oats, beans, apples, nuts, seeds, oranges and berries.
  3. Insoluble fiber remains intact as it passes through the digestive tract. Sources include; whole grains, wheat bran, seeds, carrots and other vegetables
  4. Only 1 in 10 North Americans get the recommended 25-40g of fiber per day!
  5. We eat about 33% less fiber than we did a century ago (a rough(age) estimate).
  6. Fiber works magically in the digestive tract as it slows down the passage of food in the stomach and speeds it through the intestines. It also promotes the growth of beneficial bacteria
  7. Fiber slows the release of blood sugar, which helps keep weight and type II diabetes at bay.
  8. Fiber has a modest effect on cholesterol but its real cardiovascular benefit is in its effect on C-reactive protein – a marker of inflammation that is far more telling than cholesterol when it comes to heart disease risk. Ones study showed that those who ate about 22g of fiber had an average of 63% lower levels of C-RP than those who ate about 10g.
  9. One study showed that adding 10g of fiber resulted in a 20% decrease in heart attacks.
  10. A study of over 400 adults with previous suicide attempts found only 2 nutritional differences between them and the control group without such history. One of them was low fiber intake (the other was polyunsaturated fat intake). This may not be causative but it’s interesting.
  11. Interestingly, fiber consumption does not appear to reduce the risk of colon cancer
  12. Those who suffer from IBS may even benefit from the elimination of certain fibers such as bran to reduce abdominal distress
  13. Eat plenty of fruits, vegetables, beans, seeds nuts and whole grains to get your fiber intake up. A gradual increase is best.


  1. American Journal of Clinical Nutrition, April 2006; vol 83: pp 760-766
  2. Nutrition (2005)
  3. New England Journal of Medicine. 342: 1149, 2000
  4. Journal of the American Medical Association Feb. 1996 447-451
  5. Digestive Diseases and Sciences (2005)
Filed in Supplements,


  1. Amy

    Great to see you writing the health benefits of fiber. We just don’t eat enough! It is also a weight loss tool everyone needs to add to their toolbox.
    Thanks for great information!

  2. Enrique

    Great article! Fiber is very important to maintain a healthy life style. I’ve been adding extra fiber in my diet for the past 13 years. What I’ve noticed personally is that I have been able to maintain a steady weight, I don’t feel as hungry, I usually don’t feel that low you get right after having lunch (because of the excess of empty carbohydrates), I’ve maintained my sugar levels steady and I’m more regular in the bathroom. People are becoming more aware on the important of fiber. Now at days you can find more products that are richer in fiber such as past, bagels, yogurts, cereals, snack bars, etc…

  3. Becki

    Well see i agree with most people sure fiber is yummy like breads and what not….. I am a sixteen year old chef and of course i took many courses in school about food and learned that too much fiber is bad…..thats why i set my limits….i am a very diet oriented person if theres a new diet…IM ON IT lol…. So if anyone has some dieting tips please email them to me my email is

  4. vegangirl

    Kailash said:
    And carbs aren’t essential, not the way that fats are. Whoops![…]

    Carbs are actually essential to proper brain function as the brain runs mainly on glucose. provides further information.

  5. rhinolink

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  6. Spectra

    Although it may be true that humans seek out high energy-dense foods, humans are also a very versatile species and we can get nutrition from lots of sources. Sure, animals, fish, mollusks, etc., may be some of the best sources of certain vitamins and minerals. But vegetables and fruits and other plants are also extremely good sources of antioxidants and other vitamins and minerals. Berries, dark greens, nuts, avocados, tomatoes, carrots, etc., are consistently among the healthiest foods lists. I don’t think I would consider grains in the same class as other plants because I’m pretty sure humans didn’t usually eat grains back in the day because they required too much work to get at the actual food matter. But to say that vegetables will kill you is a pretty narrow viewpoint.

  7. Fromper

    Kailish, as a vegetarian (nearly vegan diet), I really feel the need to educate you on some things.

    Different plant sources of protein contain different amino acids, and soy is the only “complete” protein besides meat. So to get all the essential amino acids, vegetarians either eat soy or else a combination of various other protein sources. But to say that we need to eat double the quantity of food is just silly. If I eat 10g of protein in a food with some essential amino acids, and 10g of protein from another food with the other esseintial aminos, the combination is roughly the same nutritionally (from a protein standpoint) of eating 20g of meat protein. The difference, of course, is that my 20g of protein doesn’t come with cholesterol and extra unneeded fat.

    I find it interesting how you claim that flax and chia are the only plant sources of omega-3, then you name another plant source later on in the same paragraph (walnuts). And seaweed is another major one. Not something that most people eat regularly by itself, but in today’s environment, it’s added as an omega-3 supplement to many other prepackaged foods. For instance, I drink vegan soy milk fortified with omega-3 from seaweed. So I get my omega-3 the same place as the fish you eat – I just cut out the middle man.

    I’d never heard of choline before seeing your post, so I googled it. The first few sites I found all listed different dietary sources, but all of them included vegan sources, many of which I already eat regularly – soy, tofu, peanuts, peanut butter, lentils, flax seeds, oats, navy beans, almonds, cauliflower, etc. Guess I’m safe there.

    Non-animal vitamin D sources? I live in Florida, so sunlight’s a good enough source for me, year round. But that fortified soy milk I mentioned earlier has just as much as fortified cow milk.

    I don’t really worry about absorbing all the vitamin A I consume. When you eat carrots regularly, you’ll absorb enough eventually.

    Again, I’d never heard of taurine, so I googled it. The sites I found said that most adults make their own taurine, so consuming it in your diet isn’t necessary. Same with carnitine, apparently.

    Obviously, I’m no expert on nutrition, or I wouldn’t have had to google several of the nutrients you mentioned. But I know who the experts are, and I’ve seen the report by the American Dietetic Association saying that a vegan diet can be perfectly healthy for people in any stage of life. Obviously, a little planning is necessary, but the same holds true for any diet. I notice they’ve never published such a report about a meat-only diet…


  8. Kailash

    Dr. J said:
    He’s probably referring to a lack of Vitamin B-12, Linds. It’s an easy supplement to take and not a good reason to avoid a plant based diet if that is your desire. It can be found in plant sources, but they are not considered totally reliable. […]

    There’s a helluva lot more than just vitamin B-12 to be found in animal foods.

    Popular plant sources of protein, such as grains and beans, only contain about half the amino acids as animal foods. So you’d have to eat double the quantity for a roughly equivalent amount of nutrition. Only, there are carbs in addition to the protein you just ate. And carbs aren’t essential, not the way that fats are. Whoops!

    Now, the only true plant sources of omega-3 fats are flax and chia seed. Your two favorite foods, right? Yet, your brain is 30% omega-3 fats. Tropical oils are nice, since that’s about the only way a vegan can get their essential saturated fats. But all other plant oils are pro-inflammatory, including nuts, grains and legumes. And your favorite walnuts? Those are a 5:2 ratio of omega-6 to omega-3. Now you gotta eat flax seeds to make up for it. But, here’s a problem, too many polyunsaturated fats will cause aging as they are so easily oxidized. Whoops again!

    Choline (Vitamin Bp) is scarce in plants. That’s the precursor of the neuro-transmitter acetylcholine. So too with Vitamin D, and its scarcity in plants. In fact, it’s only found in mushrooms. And most plant forms of fat-soluble vitamins, such as vitamin A, are poorly absorbed. Also, plants do not contain the conditionally essential amino acids taurine or carnitine.

    If you eat only vegetables (vegan), you are relying on the body to synthesize a terrible number of essential nutrients from the plant form. You’re basically running on starvation mode, doing as such, relying on a safe-guard given to most of us by evolution. I say most of us, as many have trouble with the synethsizing pathways. Their ancestors apparantly had better eating habits.

    Vegans are screwed. Vegetarians have enough trouble as it is, unless they make dairy and eggs their primary food group. And anybody, even omnivores, will have trouble with polyunsatuate balance, unless they eat plenty fish.

    Are we really “all dying”? I seem to be getting stronger and healthier as time passes, and I learn more about the effective diet. Yet, some others are clearly wasting away.

    I’m sorry if it runs counter to your sensibilities, but our ancestors were not veg-heads. Blame them for eating so many animals, if you like. But realize you wouldn’t have the capacity to ponder these things, if they hadn’t.

  9. Heather

    Linds said:
    Tyson Foods?[…]

    omg – I just laughed out loud! Two points for you.

  10. Fitness_Fanatic

    Kailash, remember we’ve been evolving a long time since we strictly were eating mollusks. Omnivore means plants as well as meat. I think you just are looking for any excuse to not eat your veggies!

  11. kells

    Hate to break it to you – but we’re all dying. Including people who survive solely on mollusks and large game.

  12. Dr. J

    He’s probably referring to a lack of Vitamin B-12, Linds. It’s an easy supplement to take and not a good reason to avoid a plant based diet if that is your desire. It can be found in plant sources, but they are not considered totally reliable.

  13. Linds

    Kailash said:
    Vegetable only. You will die.[…]

    *chuckle* Good thing most people have heard of fruit, beans, nuts, pulses, and legumes.

  14. Kailash

    Julie said:
    Meat only diet? I’d rather shoot myself. I don’t believe that anybody with an ounce of sense believes that’s healthy. “Somebody said”, indeed.

    Meat only? Possible. Vegetable only. You will die.

    Spectra said:
    I guess if you’re eating lots of wild greens, berries, roots, barks, etc., you’d get a lot of fiber.

    Bark?? Your ideas of the paleo diet are complete nonsense.

    We tend toward calorically dense foods. EVEN in modern times, when food is more than plentiful. (“I see… fat people.”) Let alone when food was hand to mouth.

    It’s called survival. And our ancestors ate more meat than you’d think. Enough, sufficient, to evolve a huge brain that is 60% fat.

    Believe you me, that wasn’t from refining corn oil. Nor are we avacado-vores or coconut-vores (those aren’t found in Africa). And our brain isn’t mono or sat fats, anyways. It’s 30% DHA, an omega-3 fat found only in quantity in marine animals and ruminants. Mostly in the marine animals.

    We are the product of voracious consumption of mollusks. Archaeological digs in Africa prove as much. The women gathered mollusks while the men hunted antelope. It’s right there, written in stone (fossils). Anybody who says otherwise is a liar, justifying dietary priesthood.

    I love animals as much as anyone else. Some of them I love in the forest, and some of them I love on my plate. But I love them all, including myself, which is more than a self-sacrificing and dying vegan can ever say.

  15. Julie

    Meat only diet? I’d rather shoot myself. I don’t believe that anybody with an ounce of sense believes that’s healthy. “Somebody said”, indeed.

  16. Fitness_Fanatic

    Linds said:
    Tyson Foods?[…]

    Bodybuilders swear by raw-meat only diet.

  17. Linds

    Fitness_Fanatic said:
    Some have recently said that vegetables are not meant to be eaten by man. That we should only consume animal flesh.[…]

    Tyson Foods?

  18. Fitness_Fanatic

    Some have recently said that vegetables are not meant to be eaten by man. That we should only consume animal flesh.

  19. Heather

    I eat lots of fiber – hard not to when you eat a lot of vegetables and whole grains. Makes me feel 100x better — fiber is pretty close to a miracle, in my experience, at improving how you feel.

  20. RooGrrrl

    I’m curious about the link between fibre consumption and suicide. When was that study done, and by whom? Is there a link to more information about that study? Where can I find out more?

  21. Spectra

    I’m one of the 10% of Americans that does get the recommended fiber dosage each day. I eat a lot of fruits and vegetables and whole grains, so I definitely don’t need a supplement. Just be sure to drink a lot of water to make sure everything moves through your system smoothly. I also have IBS and I’ve found that consuming enough fiber every day actually helps to decrease my symptoms.

    @Kailash–I can see how eating WAY too much fiber could possibly cause problems (decreased nutrient absorption is one of them), but I doubt anyone would be able to eat that much fiber at once. You won’t blow out your colon eating too much fiber if you spread out your consumption throughout the day. What you don’t want to do is take a lot of fiber supplements without sufficient water because they can expand in your intestines and possibly cause a blockage. You don’t usually get that problem with fruits and veggies because they are mostly water anyway. I’m pretty sure that people back in the day (before refined grains came into being) probably ate at least 40g of fiber a day. I’ve even heard that ancient people ate as much as 100g per day with no apparent problems. I guess if you’re eating lots of wild greens, berries, roots, barks, etc., you’d get a lot of fiber.

  22. soozeequeue

    I think that it doesn’t matter what kind of food you are talking about, there is always the danger of too much of a good thing. But that’s talking about when people go to extremes, and most people don’t. A couple of years ago, I decided to add a lot more fibre to my diet. (foods I ingested, not supplements) Before I did it I checked it out with my doctor, and different other sources, and what I learned was that the most likely consequence of too much fibre (I mean, maybe 100-200 percent of the RDA, not going to extremes) would be an upset stomach, maybe some additional gas for a couple days, while my body adjusted. And that’s pretty much what happened, but the benefits sure outweighed the minor negatives.

    I have probably settled at around 100%, some days a bit more of my RDA of fibre. I’m not really counting but I guess I get around 25-30g, from a variety of sources, all things I really enjoy – the fruits, veg, whole grains, nuts and beans that article talks about. I would think that gives you a nice balance of soluble and insoluble fibre but haven’t checked the numbers, I admit. And if for some reason I veer from that I really miss it, not just physically but emotionally too. It just makes me feel better all around to eat that way.

  23. Susanna

    E. said:
    Does it matter if it’s soluble or insoluble fiber?[…]

    The quick answer is you need both – but in what concentrations???

    Insoluable fiber helps with promotes bowel regularity and reduces the risk of colon cancer and other colon problems.

    Soluable fiber helps regulate blood sugars and thus weight control.

    I also learned from a friend who is a micro-biologist doing research for NIH that his team has discovered that soluable fibers also help to remove “bad” bacteria from the stomach and out of your system by absorbing them. Though the research is still in progress, it looks like it will be another good reason to eat fruits, vegetables, oat bran, etc…

  24. Kailash

    Fiber has its dark side as well.

    Someone even wrote a book about it, “Fiber Menace”:

    Though, this was written by someone who practically blew out his colon from eating too much fiber. So it really should be taken with a grain of salt. But, with that caveat, there is some very good information presented.

    That said, I think the recommendations on fiber are set too high. If a person is regularly eating fiberous produce, such as fruts, vegetables and nuts, then they’re getting plenty fiber to see the most beneficial results.

    I would never go so far as to take a fiber supplement. That’s not the way to move stools, which should be passed by peristalsis, and not so much by sheer bulk.

    As for weight loss, a person should already be turned on to vegetables, as a part of their new, normal dietary intake. There’s really no reason to pay one’s attention toward getting “X amount” of fiber, if doing everything else right.

    The problem is that “X amount” of fiber might be enough to cause some very real complications, if we set “X” too high. And for a lot of people, bigger is better, especially when the pounds don’t seem to be dropping fast enough.

    Just be careful in this regard, and stick to whole foods when you can.

  25. Mike OD

    Eat fruits and vegetables and you will get all the fiber you need. Of course get rid of processed foods as well.

    Avoid BRAN…it’s an anti-nutrient and marketing gimick. Here’s a good overall info page on it:

  26. Never teh Bride

    I’m one of the IBS-ridden folks mentioned in the list and fiber has DEFINITELY worked for me. Love it!

  27. Ali from The Office Diet

    I find that high-fibre foods fill me up more (and I tend to have to chew more, so eat slower.) Did anyone else ever try the F-plan or is that a UK thing? It was a high-fibre low-cal diet plan in (I think) the 1980s — I borrowed my mum’s book as a teenager!

    I was interested to read this:

    “Only 1 in 10 North Americans get the recommended 25-40g of fiber per day!”

    In the UK, the recommended minimum is 18g.

  28. E.

    Does it matter if it’s soluble or insoluble fiber?

  29. M Collard

    In regards to weight, I’ve lost 40 lbs by eating high fiber diet and eliminating processed foods. I’m now “maintaining” and enjoy processed foods from time to time but high fiber foods are the majority of choice. I also noticed that I can eat more quantity of high fiber foods without any significant weight gain (carb ratio for fruits, vegetables and seeds is significantly lower than most processed foods).

  30. thehealthblogger

    Very concise and beneficial. As soon as I started eating more fibre-rich foods as well as more greens (in particular, cruciferous vegetables), my skin problems totally disappeared.

  31. Mark Corner

    Thanks for the informative post there are lots of things in that list that Ican take away and use in my eating habits. Methinks I don’t eat nearly as much fibre as I should do, time to re-hash the food list next time.