I have started to change my diets two years ago, and are now eating large amounts of fiber every day - 'large amounts' meaning far above the recommended 30 g, typically 100 - 150 g per day.
I have read about possible complications like abdominal pain, bloating, diarrhea, or constipation; I have none of these, I am doing fine with it for months.

Question: are there any known short or long-term adverse effects from such high fiber intakes?

2 Answers 2


Not at all. Studies have shown that a large amount of fibers is a protective factor against colo-rectal cancer for example. Actually, as you said, only effects are some digestive troubles, since fibers are cut and destroyed by bacterias in colon : those bacterias produce gas, that's why you might feel uncomfortable. But if you don't have that, go on !

One important point : you don't have to REPLACE something by fibers. I mean, it's good to eat a lot of fibers, but not only fibers. Don't forget proteins !

  • Overall good answer, please do add some references.
    – L.B.
    Mar 22, 2017 at 15:41
  • Welcome to Health.SE. Since health is an important topic, the site has a strict policy that all answers should be backed up with reliable references, in order to provide the community with the means to assess the merit of the answer, regardless of the reader's background. See Health Meta for a list of reliable sources. If you still have trouble with this, feel free to visit the help center or take the tour.
    – Narusan
    Mar 22, 2017 at 15:57

There are no negative consequences, IF you eat in the proper way.

With this statement I am referring to eat every component of the diet, like carbs, fats, proteins, vitamins and of course fibers. This is essential.

The main problem with people that eat lots of fibers, is that they feel full fast and usually won't eat all the proper components. Problems you have provided, like abdominal pain, bloating, diarrhea, or constipation are in fact caused of not eating good enough: vitamins deficit can lead to abdominal pain, coagulation problems and so on; protein deficit can leat to muscular problem, problems in the healing of scars or in general dermatological problems and so on.

So, eating a lot of fiber has no side effect if you integrate the other component of the diet.

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