I read this highly informative article from Gut Sense on the causes of hemorrhoids commonly known as piles. The article argues convincingly that eating too much dietary fibre can cause Hemorrhoidal disease. I quote:

Hemorrhoidal disease and anal fissures start with a little "defect" in human anatomy — the anal canal that is too darn tight for large and/or hard stools to pass through. When these abnormal stools get stuck inside your colon or rectum, you may have no choice but to strain, gradually causing yourself hemorrhoidal disease, anal fissures, and other complications...

On the other hand, if the stools are large, let's use a pickle — something we can both relate to without looking at the "real thing" — to compare its size with the anus. As you can see even a smallish Corby pickle is huge relative to the anus size. And not just the anus — the pickle is about the same size as the entire rectum...

So, if anyone is telling you to "eat more fiber" to "bulk up" your stools, so you can relieve or prevent hemorrhoidal disease and anal fissures, give that person a Corby pickle, and ask him or her to jam it up their anuses, and, then, tell you how normal it feels. If that experience does not get them out of the pickle you got yourself into with painful hemorrhoids or bleeding fissure, nothing will...

What giveth? Newton's third law, of course: for every action there is an equal and opposite reaction. Here's what I mean:

● As hemorrhoids get larger, the anal canal aperture gets smaller, and the stools become harder to pass;

● As the difficulty of passing stools intensifies, the need to strain grows more pronounced, and the hemorrhoidal pathologies turn worse;

● As the first two problems evolve, people often keep increasing the amount of dietary and/or supplemental fiber to counteract defecation difficulties;

● As people increase the amount of fiber in their diet, their stool keep getting larger, causing further enlargement of hemorrhoids, while the anal aperture becomes smaller and smaller;

● As the anal aperture becomes smaller and the stools larger, people experience more constipation, strain harder, feel more pain, and begin experiencing anal fissures and other complications described elsewhere on this site and in my books.

If this chain of events isn't interrupted by luck, education, or God's will, the vicious cycle continues unabated until patients require surgery to fix rectal prolapse, anal fissures, fistulas, abscesses, fecal incontinence, or other related ailments.

The video in the article explains clearly what are hemorrhoids. However, the general consensus is that a high fibre diet helps to prevent Hemorrhoidal disease. I am very interested to know whether this is a myth.

  • I was wondering whether this only refers to fibre as a supplement, or also to naturally-according fibre within food-stuffs: gutsense.org/gutsense/… shows it includes naturally-accoring fibre, "As I already explained in my book, here, and pretty much elsewhere on this site, fiber from fruits, vegetables, grains, bran, and laxatives is the PRIMARY cause of chronic, persistent constipation and related colorectal disorders."
    – ChrisW
    Commented Dec 4, 2013 at 11:25
  • I found this related question on fitness exchange. Commented Dec 5, 2013 at 3:42
  • With all this talk of pickles, my first thought is that in the proposed model of causation, anal sex must either cause or prevent (pre-stretching?) the listed maladies. o.O
    – Weaver
    Commented Oct 16, 2014 at 21:52

2 Answers 2


It is fine to have a plausible theoretical model of what might happen when eating more fibre, just so long as the theoretical model matches the actual experimental data. When it doesn't, it is time to rethink the model.

What does the experimental data show? Well, we have a good source here:

Their summary?

Trials of fiber show a consistent beneficial effect for symptoms and bleeding in the treatment of symptomatic hemorrhoids.

So, we can dismiss the conjecture described in the question, because it doesn't match the data.

How was this summary reached? Well, this isn't merely one small experiment. It is a systematic review, which means they carefully searched for existing studies, where possible consolidated the data, and drew a conclusion from that.

They found seven quality trials, totalling 378 patients (fiber + non-fiber control)

The risk of not improving/persisting symptoms decreased by 47% in the fiber group [...] and the risk of bleeding by 50% [...] consistent results over time. [...] One study suggested a decrease in recurrence.

Details about RR, Confidence Intervals, and some non-significant trends are available in the report.

Please don't use this as medical advice; if you have symptoms of haemorrhoidal disease, see your doctor and follow their advice.

  • Thanks for referencing a scientific study. I was wondering why the objective of that study mentions laxative instead of fibre. Interesting to note is that it is a comparison between fibre and no fibre group. I was looking for one that analyses normal diet vs a high-fibre diet. That is, whether too much of a good thing actually reverses the benefit. Commented Dec 5, 2013 at 3:41
  • 1
    @QuestionOverflow: They are talking about patients taking additional fibre to their regular diet. (Given they were already sufferers, we might expect their diet to be lower in fibre than the average, but assuming that would beg the question.) Fibre is a laxative, which explains the word choice. The actual details of the fibre depended on the study (e.g. Stercullia, Isphaghula Husk, Psyllium seed) for varying dosages and time periods.
    – Oddthinking
    Commented Dec 5, 2013 at 4:07

According to Medline Plus, a common cause of hemorrhoids is straining during the bowel movements. Straining can be due to constipation.

PubMed (A systematic review and meta-analysis)

Trials of fiber show a consistent beneficial effect for symptoms and bleeding in the treatment of symptomatic hemorrhoids.

Insoluble fiber absorbs water and makes stools softer, but quite surprisingly, it seems a soluble fiber may provide better constipation relief than insoluble fiber. Nutrientsreview

In individuals with irritable bowel syndrome, insoluble fiber may even worsen constipation.

Wiley Online Library

Indeed, in some cases, insoluble fibres may worsen the clinical outcome [in constipation-type IBS]

My conclusion: High-fiber diet may help prevent constipation and thus hemorrhoids, but in some people with irritable bowel syndrome, insoluble fiber can worsen constipation and thus potentially worsen hemorrhoids symptoms.

Dietary fiber can have a stool-softening effect only when consumed with sufficient amount of water.

  • 1
    I suspect an important issue is to increase your level of hydration so the fibre can have the intended softening effect (rather than just increasing "productivity").
    – user18604
    Commented Oct 16, 2014 at 14:18
  • Yes, water is needed for fiber to have a softening effect on the stool. The water can come from the same foods as fiber (fruits, vegetables, oatmeal...), from beverages or from intestinal juices. This means you often do not need to drink significantly more water as usually for fiber to work.
    – Jan
    Commented Oct 16, 2014 at 14:52
  • 1
    one of the functions of the bowel is to remove water from your stools, so even if you eat food with sufficient water in it already, if you become dehydrated afterwards, one of the places your body can try and get fluids is from your stools, so you need to keep hydrated. Being constipated is an indication that you may be dehydrated in the first place, in that case adding fiber will only make that worse unless you do drink a bit more as well.
    – user18604
    Commented Oct 16, 2014 at 15:06
  • Yes, I agree, fiber in a dehydrated person may not work as intended.
    – Jan
    Commented Oct 16, 2014 at 15:12

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