4 Good Reasons not to add fibre to your diet.

Nutritionists have been telling us to pump up the fibre in our diet for 44 years.  But the evidence is now in.  Not only is that pointless.  In at least one case, it is very likely to be harmful.

In 1971, Dr Denis Burkitt, an Irish Surgeon, published a paper based on his observations of life in Uganda, where he lived at the time.  In it he hypothesised that a lack of dietary fibre was the cause of much that then ailed Western Society.  He thought it caused bowel cancer and probably also heart disease, Type II Diabetes, varicose veins, obesity, diverticular disease, appendicitis, gallstones, dental cavities, haemorrhoids, hernias and constipation.

Dr Burkitt had noticed that native Africans produced on average four times as much poop as English boarding school children and did so at three times the speed.  He felt that this was because of all the fibre they ate.  And he theorised that the, ah, high rate of flow meant that there was less time for cancer causing foods and impurities to be in contact with our insides.

It was an idea whose time had come and the good doctor quickly became ‘fibreman’, releasing a best-selling book on the topic (a page-turner called ‘Don’t forget Fibre in your Diet’) and crusading ceaselessly for the addition of fibre to the Western diet.  He is famously quoted as saying “America is a constipated nation…. If you pass small stools, you have to have large hospitals.”

His simplistic guess was swallowed whole by the medical and nutrition communities and heavily promoted by those who stood to gain the most from it (largely the Breakfast Cereal Manufacturers).

The shopping list of things fibre is supposed to prevent has gotten shorter as science has delivered better evidence on their real causes but it is still impressive.

To this day, the DAA (Dietitians Association of Australia) claims that eating ‘at least 25-30 grams of fibre a day’ will ‘reduce the risk of constipation, diverticular disease, haemorrhoids and bowel cancer.’ They also mention it will ‘lower the risk of [heart] disease.’

Unfortunately (as is often the case with claims made by the DAA) there is no credible evidence that any of that is true.

Bowel Cancer

In 2002 the highly respected Cochrane Collaboration reviewed five high quality randomized controlled trials involving 5,000 patients.  They concluded that there was no evidence to suggest that increased dietary fibre would reduce Bowel Cancer.

That review was followed up in 2005 by a major evidence review by the Harvard School of Public Health.  The paper covered 13 studies which involved 725,628 people.  And again fibre drew a blank.  The authors concluded that high dietary fibre intake did not reduce the risk of Bowel Cancer.

Heart Disease

The theory goes that fibre is supposed reduce heart disease risk by lowering our ‘bad’ cholesterol. Once again though the research community is being singularly unsupportive.

While oats do lower cholesterol, trials on other types of fibre show that it doesn’t, good, bad or otherwise.

And when it comes to the only thing that really matters, there is no evidence that fibre reduces the risk of dying from heart disease (or anything else).

Constipation and Haemorrhoids

Fibre is supposed to cure constipation (and all its travelling companions, including haemorrhoids, bloating, anal bleeding and abdominal pain).

Believe it or not, this is simply based on Fibreman’s observation of high-flow Ugandans.  They didn’t seem constipated so ramping up the fibre is sure to cure the Western blockage.  Once again though, the evidence has not been kind.

Studies have repeatedly failed to detect that patients with constipation eat less fibre than people without it.  Worse (for the Cereal Industry), those studies have observed that there is no benefit for constipation when fibre is added to the diet.

But something really interesting happens when you reverse the treatment.  A recent trial measured the effect of removing fibre from the diet of people with constipation, with spectacular results.

Six months after the added fibre was removed, ALL of the (initially) constipated patients no longer suffered from constipation, bloating, bleeding or pain.  In contrast the folks who stayed on high fibre diet still had all of those problems.

Diverticular Disease

The news is significantly worse when it comes to Diverticular Disease, an extremely common and painful condition affecting more than half of all people over 70.

As early as 1981, clinical trials were finding that fibre was no help at all.  One author even concluded that the suggestion it might was “simply a manifestation of western civilization’s obsession with the need for regular frequent defecation.”

But much more worryingly, one significant recent study concluded not only that fibre didn’t help but that it increased the likelihood of contracting the disease.

The evidence is now in.  Just like so much of the dietary nonsense we’ve been fed over the last half century, fibre for disease prevention turns out to be twaddle that benefits nobody except the people flogging us whole grain cereals.

A combination of ignorance, arrogance and negligence (with a sizable smattering of corporate profiteering) has kept the eat-more-fibre message front and centre for all nutritional advice.   But we didn’t need added fibre before 1971 and we still don’t need it.  Worse, it is likely to be adding to the burden of diverticular disease (at least).

An Irish doctor’s theory about prodigious Ugandan turds has ensured the rest of us have been fed crap for the last four decades.  But that needs to stop now.  The DAA needs to step up and change the message – even if that is likely to really annoy its cereal selling sponsors.


Image: DAA Corporate Partners (via the Grains and Legumes Nutrition Council)

Join the discussion 43 Comments

  • funny how epidemiological arguments always succeed in bringing up high-fiber healthy populations but fail to bring up low-fibre healthy populations (Inuit, Mongols, some Northern European & African populations)

    great post

  • Sue says:

    Raphael – small localised populations like the ancient Innuit made metabolic adaptations to their available diet. That doesn’t make the ancient Inuit diet ideal for the rest of the world – it was utilising what they had available to stay alive.

  • Yet again, so disappointing. The medical profession says “Don’t use alternative treatments, stick to evidence-based medicine” and now we find the advice of the health authorities is NOT evidence-based at all.

  • Luke McMahon says:

    The main reason we need fibre is for our gut microbes. Scientist, Jeff Leach, who studies gut microbes is, I believe, the go to person on fibre.

    The following is taken from an article at: http://www.eatingwell.com/nutrition_health/nutrition_news_information/how_good_gut_bacteria_could_transform_your_health?page=2

    He’s [[eff Leach] since done several variations of this diet—adjusting fat, carbs, protein and fiber. “It’s the fiber that’s the game changer,” Leach says. Adding 40 to 60 grams of fiber per day seems to shift his gut microbiome toward a diverse, more beneficial mix of microbes.

    Here’s why: like all living things, bacteria need food to survive. They do that by fermenting—that’s the way these guys “eat”—dietary fiber. But gut bacteria are picky. Only certain types of fiber will do—and most of us don’t eat enough of the kind that bacteria need.

  • Jane says:

    Oh God when will it stop! You should also investigate high carbohydrate diets recommended for Type 1 Diabetics. Insanity at its best. Keeping the billion dollar Diabetic industry thriving. Thank you for keeping it real.

  • graham lerwill says:

    With respect, this article contradicts the message in sweet poison – which one is true, or truer?

  • David Gillespie says:

    How does it do that Graham?

  • Simon Edmonds says:

    In Sweet Poison you said that the fructose contained in fruit was only a problem if consumed in the form of juice – minus the fibre. That fruit consumed whole did not seem to have the same detrimental effects….

  • Simon Edmonds says:

    I thought the same as you, Luke. My source is Professor Katherine Samaras who is a senior staff specialist in endocrinology and metabolism at St Vincent’s Hospital in Sydney and a senior researcher in obesity and diabetes at the Garvan Institute of Medical Research. I heard her being interviewed by Margaret Throsby on ABC Classic FM on 9 Sept 2014. She says you may as well eat dirt as spend a lot of money on pro-biotics as all the good gut bugs are found in soil. Then she goes on to say that fibre is the food for the good bugs and sugar(both complex and simple-specifically she says glucose) is the food that promotes bad bugs. Gut bugs govern the immune system and so if you feed the bad bugs you will get an inflammatory reaction (glucose stimulates T lymphocytes) but this effect can be reversed by reducing your overall calorie intake. And so on, hear the interview at the link below:

  • David Gillespie says:

    I’m still not clear how this article contradicts that message Simon

  • Simon Edmonds says:

    So are you saying the article is only aimed at discrediting the supposed benefits of fibre for the 5 conditions mentioned? Because it seems I am not the only one who has misinterpreted your message to be that there is no benefit in dietary fibre at all. Perhaps some clarification is necessary.

  • Simon Edmonds says:

    OOps, 4 conditions

  • David Gillespie says:

    Simon I assume that people reading my posts understand that I oppose fructose consumption and they should be read in that context. I guess if folks want to keep consuming fructose then consuming it with fibre is less harmful than consuming it without fibre (in a few pieces of fruit). But that is quite different from suggesting people should explicitly seek out added fibre or attempt to consume more fibre (which is current advice). This article is pointing out the supposed virtues of added fibre turn out (like much of modern nutrition advice) to not only be nonsense but in some circumstances, probably deleterious.

  • James Knoesen says:

    The fibre found in fruit is insoluble. That’s why it’s good for you. The article is lacking in that it doesn’t distinguish between how important insoluble fibre (from vegetables, fruit etc.) is compared to soluble fibre (cereals, psyllium etc.). ALL of the fibre being mentioned in the article is additional soluble fibre and this is why the effects are bad. Insoluble fibre is much more important – it is essential for the absorption of micro-nutrients and also helps to regulate blood sugar levels.

  • Jimmer says:

    How does fibre NOT help constipation? Try eating a whole foods diet for a week and you’ll turn into a soft serve machine.

  • Debbie says:

    I agree, this is all very strange and misleading. What type of fibre are we referring to? If it’s a lie that we need added fibre then how much fibre do we need? I’m also hanging out to find out what the Ugandans were eating or doing that so increased transit time and number if movements. Is it possible that they were very active and if we can’t match that level of activity maybe we need fibre to defecate efficiently. Who knows? I think people are at the point of been driven mad by all the conflicting information. The lack of a traditional diet is the real issue here. Food is medicine but we shouldn’t need a prescription for it.

  • David Gillespie says:

    We need exactly the amount of fibre we get from eating real food Debbie.

  • Monica martin says:

    Actually the Inuit diet is perfect for everyone – science proves this time and time again.

  • David Gillespie says:

    Got a link to the science that proves this Monica?

  • Chris says:

    For anyone interested, this is all laid out nicely in Fibre Menace by Konstantin Monastyrsky. There are cultures (e.g. the Japanese) who eat a very low fibre diet and do not suffer from any of the usual diseases we are told fibre cures.

  • Nick D says:

    It’s interesting that the microbiome work is finding a causative benefit of fibre now. Most of that work is concluding that fibre is the essential thing to maintain a healthy gut community of microbes. It’s also showing why sugar for example may be as destructive as it is, with its effects on particular microbes in the gut. So for example when they combine the microbiology with the anthropology, African hunter-gatherers – who eat vast quantities of fibre – have much more diverse microbiomes than ours. They’re still pondering what that all means, and whether it also helps to explain the deposition of fat in a creature, which some experiments seem to to suggest is the case.

  • Nick D says:

    And just noticed others have talked about this link above, apologies.

    I discussed the microbiome work with Gary Taubes. He was a little sceptical, he thought the mechanisms around insulin for example explain what’s going on pretty satisfactorily. But for a variety of reasons I suspect the microbial ideas are going to be decisive, and won’t necessarily contradict the message that carbohydrates, including fructose, are a major cause of metabolic disorder. What microbes help to do though is show why people get differential responses from cutting out these carbohydrates, for example – it may be due to their specific microbial make-up. My wife is an example, she cut out most fructose and refined carbs together with me a few years ago now, but it didn’t have the effect on weight that she would have liked.

    Another very interesting piece of research is around prebiotics – the analogy being that these cultivate the ‘soil’ microbes get to live in. One Scottish researcher (surprise) has found that having people eat a large bowl of porridge daily has profound, positive effects on their gut microbes. She believes that the number and diversity of microbes in guts is so vast that trying to engineer particular effects there deliberately is a needle in a haystack exercise. But you can cultivate the ‘soil’ to favour better microbe balance, such as she’s discovered with oats.

  • Kelly Bamback says:

    WOW, thankyou!! will listen to this!

  • Kelly Bamback says:

    Can you remember the researchers name? Sounds very interesting

  • Rachel says:

    Hi David, Google Vilhjalmur Stefansson. He is an Icelandic born, Harvard educated scientist who lived with the Inuit people for 10 years eating nothing but 2% carbs, 15% protein and 83% blubber (fat). When he returned home his peers called him a liar, so he had himself locked in a New York research hospital, where the naysaying doctors had to deem their experiment a FAILURE because he was perfectly healthy.

    He suffered with no cardiac problems, his had no vitamin deficiencies. Dr Phinney and Dr Volek (sp?) have since furthered this study, google their names for more information. Many papers have been published blowing all this ‘five a day, high carb’ garbage out of the water

  • Rachel says:

    Let’s never forget that at one point doctors were promoting cigarettes as ‘good for you’. Trust the science. The science doesn’t lie!

  • Rachel,

    Here’s the link to the 1930 scientific paper on the Stefansson experiment: all meat, all the time, for a year: http://www.jbc.org/content/87/3/651.full.pdf

    No added fibre! What happened?

    Well….nothing really. No scurvy, no problems at all. That’s because all-meat diets are perfectly healthy, as long as the bulk of the meat is fat.

    Claims by the DAA that “plenty” of fruit & veges and especially “wholegrains” – all up, 14 serves a day for adult males! – are required for good health are based on nothing credible.

    So too, traditional claims by the DAA and other parrots that our brains “need” carbohydrates – at least 130 grams per day is best – are false, again based on a misreading of simple facts.

    The amount of carbohydrates humans need per day is zero grams. Count ’em: zero grams.

    Indeed, much of what the DAA promotes – including “an inverse relationship” between sugar consumption and obesity – is complete non-science.

    Unfortunately, the bottom line in all this is that the National Health and Medical Research Council’s Australian Dietary Guidelines on fibre, carbohydrates, meat, saturated fat, etc, are a jumble of false and misguided information that for decades has been harmful advice to those with a tendency towards obesity and type 2 diabetes (aka Metabolic Syndrome): pp. 33-42 http://www.australianparadox.com/pdf/PeterFitz-AustralianParadox.pdf

    That’s what happens when we import stuff from America without any competent quality control (p.36).


  • Gerald Davies says:

    The science on short chain fatty acids is much more compelling and cannot be dismissed so easily but the only dietary source of SCFA is gut microbial fermentation of fibre

  • Geo says:

    Show me the studies…right now I only think you are nothing more than a polly trying to make up ground based on your belief.

  • David Gillespie says:

    The links are in the article Geo

  • Bob says:

    My arsehole disagrees with you.

  • Stuart says:

    A good discussion. Still deciding where I stand, but as with most things it goes back to the one piece of dietary advice everyone seems to agree on – eat plenty of vegetables. Eating real food and letting nature worry about its composition tends to be a tactic that works well. It’s when we interfere that the problems arise.

  • […] and Colon Cancer [Harvard] | Dietary Fiber [Video] |  Myths and Truths About Fiber | 4 Reasons Not to Add fiber to Your Diet | Fiber Menace Reviews (real people who ate a high fiber diet based on doctor recommendations […]

  • Kim says:

    So, the next question is how does it effect weight loss?
    Is there a difference between soluble and insoluble fiber for digestion time?
    What about diabetics? There are studies that may show that some fiber reduces the timing of sugar absorption in the gut.
    Finally, is there any benefit of fiber that is naturally in food, such as in fruit, vs adding fiber to food, in reducing the speed of sugar absorption in the gut?

  • Traci says:

    I suffered from diverticulitis. I had unfortunately underwent a colon resection a couple of years ago. Ive done everything my doctor’s and a nutritionist advised me to do which was mostly a high fiber diet. I have had 6 FLARE UPS since the surgery two years ago each time visiting the ER and this last time I suffered severely from diverticulitis and I was tired of this horrible PAIN and the lack of knowledge of this disease. I read Konstantine Monastyrsky’s FIBER MENACE and my mind has been UNTWISTED! I’ve been on a very low fiber diet for 6 months and I feel AWESOME! I’ve even went from a women’s size 16 to a size 8 and yes it was hard in the beginning but man oh man I’m soooo glade and appreciate Mr. Konstantine Monastyrsky’s book . I did it the way my doctor’s adivised me ..so now I’m doing the opposite . I had my annual physical..and I have no more high cholesterol,no more high sugar,blood pressure…my doctor asked what the heck am I doing I told him to read Fiber Menace!

  • […] Constipation Research Study | Fiber and Colon Cancer [Harvard] |Myths and Truths About Fiber | 4 Reasons Not to Add Fiber to Your Diet | Myths and Truths About Fiber | Fiber Menace Reviews (real people who ate a high fiber diet […]

  • George says:

    @Rory @Rachel

    You seriously used 1 study from over 80 years ago to conclusively say that an all meat diet is okay to eat by everyone!?

    The study was carried out on 2 men for 1 year eating meat and another eating meat for 10 Days!? And you think that’s enough evidence to spout your idiotic nonsense that the whole planet can eat a whole meat diet!?

    It takes several years to develop deficiencies, not a matter of months. The study didn’t even consider heart health either. Stop with your dangerous rhetoric, preaching it as factual and evidence based. When there is not a lot of evidence to prove you right.

  • tony says:

    Traci on December 27, 2017 at 3:04 pm. I’ve had 2 recent diverticulitis flare ups from which i believe high fibre eating sessions is the cause. Rather than go through extreme pain I now intentionally eat spicy foods or bad things like salt and vinegar chips to ‘dilute’ fibre. Experiencing bad food irritation is preferable to experiencing solid fibre bricks making right hand turns in my digestive tract. I’m due for another colonoscopy.

  • Guy says:


    several years to develop a deficiency??????????
    so the sailors who developed and died from scurvy after a few months out to sea were just making things up?
    amazing how individuals are so determined to maintain their identities via a strong confirmation bias that they are unwilling to listen and decide for themselves. I am sorry, maybe co-dependency rather than bias

  • Jon says:

    It may be anecdotal but I have diverticulosis, and have been hospitalized for diverticulitis. I always do better on low fibre.

  • Danielle says:

    Amazing! I realized I do much better without fiber! I was wondering if it was just me. After cutting out lots of fiber, dairy and gluten my system works wonderfully well than when upon doctors advice I was taken fiber, bran and what have you! Your post is truly amazing! Kudos!

  • Elle says:

    What gut bacteria feed off are short chain fatty acids from fermenting soluble fibre. The great thing is that we don’t need soluble fibre to make SCFA. You can get it from foods like grass fed butter and when following a low carb keto diet then SCFA come from the beta hydroxybutyrate a.k.a ketones. The amount of science we have on our microbiome doesn’t even begin to scratch the surface of what’s really going on. The article here is all about the recommendation of a high fibre diet and the purported benefits to diseases like colon cancer and heart disease. David is showing that the science for this recommendation does not exist. And that we do not need fibre in our diet to live and even thrive because fibre is a non essential. Hence we can live without fruit and vegetables. Because everything we need and is essential is in animal based products. Phyochemicals have been shown to be beneficial not because they perform key roles in bodily processes (like vitamins and minerals do) but because they create a hormetic effect in the body making the body more resilient. But guess what? You can get that hormetic effect from other things like exercise, hot/cold baths and fasting. So, after all that: WE don’t need fruits and vegetable to survive!!!

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