The Paleo Diet and Fiber

Conventional Fiber Sources

I’ve heard it a thousand times…..fiber is essential. It supposedly helps to keep us pooping regularly, cleans out our intestines, lowers cholesterol, and slows the rate at which we absorb sugar. But is all that really true? Considering that the mainstream gets just about everything else wrong, is fiber really as important as “they” say it is?

First of all, let’s look as some examples of high-fiber food items:

  • Whole grain bread products
  • Cereals – grains, bran, and oats
  • Brown rice
  • Beans and Legumes
  • Fruits and Vegetables

All of those items sound absolutely fan-freakin-tastic, if you’re a fan of the Standard American Diet (S.A.D), and you follow the USDA MyPlate recommendations. Also, if you’re trying to live up to the government’s expectation of 20-35 grams of fiber per day, eating lots of the listed items is really the only feasible way to rack up that much fiber every day. A person can get the majority of that 35 gram milestone, just by eating one bowl of an un-named, super-high-fiber, cardboard cereal that is guaranteed to give you indigestion and horrific gas. In comparison, trying to get that much fiber from only fruit or vegetables does require a comparatively large amount of broccoli (or some other fibrous vegetable) to reach such a lofty fiber goal.

What about the Paleo Diet and Fiber?

So, going back over the list of high fiber foods, from a Paleo perspective, we can see that there really is only one, maybe two, viable options for us Paleo folks, on that list. Whole grain bread are obviously out, considering that wheat is one of the Neolithic Agents of Doom (N.A.Ds). Cereal grains and oats etc are also out, along with brown rice, because of the lectins in the husk, and of course beans and legumes are a “no-no” because of the anti-nutrients and enzyme inhibitors they contain. So, that leaves us with fruit and vegetables.

Generally speaking, we would be looking at getting the bulk of our fiber (pun intended), from some low-glycemic fruits, and preferably some green, cruciferous vegetables. Regardless, I don’t believe that obtaining a significant amount of fiber from these sources is realistic, and therefore probably indicates that our Paleolithic ancestors didn’t actually get or NEED a large amount of fiber in their diets. Don’t get me wrong, a lot of people underestimate the amount fiber that is found in most traditional diets, but in order to intake a lot of fiber, a person would often be filling up on veggies and fruit, instead of the uber-important protein and fats from meat.

But, Doesn’t Fiber Lower Cholesterol?

Most of us already know that Cholesterol numbers mean almost zero, in regards to health, heart disease and happiness, especially to us Paleo people, so why would lowering this supposedly important number be important to us? Cholesterol is necessary for good health, and hormone production, so I think I’ll keep my cholesterol, thank you very much!

What About Fiber Slowing the Absorption of Carbs?

While it’s absolutely wonderful that fiber can help to slow the absorption of carbohydrates, the majority of Paleo people generally aim for the types of carbohydrate that reside on the lower side of the glycemic index. Plus, fat and protein eaten in combination with carbohydrate has been shown to have the same glycemic index lowering effect that fiber supposedly has.

Isn’t Fiber Necessary For Regularity?

Do we really believe that the average human has no hope of depositing regular and well-formed poops in the toilet, without the aide of whole wheat bread, or pasta etc? The truth is that just like with other junk foods and sugary treats, people become addicted to additional fiber. People become dependent upon the effects of sugar, that supposedly support their energy needs, and in the same vein, people become dependent upon the “bulk building”, and “fast moving” effects of the massive amount of additional fiber we are all told to eat. They believe that without it, everything by default comes to a grinding halt.

When people switch from a S.A.D diet, to a low-carbohydrate or Paleo approach, one of the initial complaints from many “converts” is that of moderate to severe constipation. Part of this issue is caused by the lack of that beloved additional fiber, often some dehydration, and not enough dietary fat intake. This problem usually only lasts a few days to a week, and everything tends to return to “normal” after the body adapts to the recent changes in dietary intake. An easy way to counter this effect, is not to hit the local grocery store for a fiber supplement, but to actually raise fat intake for a while, using a quality fat like coconut oil. Four tablespoons of coconut oil per day, are usually quite effective at making everything slide right along, like it should.

Carbohydrates, Fiber and Cancer

There is a school of thought that suggests that fiber might actually help to cause Colon cancer. I believe this could definitely be true. After all, when cells get repeatedly damaged and repaired, sometimes mutation occurs and cancer results. Smoking, due to the repeated damage and repair to lung cells, from inhaling cigarette smoke, often causes lung cancer. In the same way, fiber literally scrapes the intestinal walls, which can also open the door to colon cancer. Check out what Barry Groves says about this, on his website:

In 1995 Dr M Inoue and colleagues published an investigation of cancers at several colorectal subsites: ascending, transverse, descending, sigmoid, and rectum, within a Japanese hospital environment. They concluded that loose or soft faeces are a significant risk factor for cancer at these sites.[v] Bran loosens and softens faeces ? that’s why it is recommended.

The following year Drs HS Wasan and RA Goodlad of the Imperial Cancer Research Fund showed that bran can increase the risk of colorectal cancers.[vi] ‘Many carbohydrates’, they say, ‘can stimulate epithelial-cell proliferation throughout the gastrointestinal tract. They conclude: ‘Until individual constituents of fibre have been shown to have, at the very least, a non-detrimental effect in prospective human trials, we urge that restraint should be shown in adding fibre supplements to foods, and that unsubstantiated health claims be restricted. . . . Specific dietary fibre supplements, embraced as nutriceuticals or functional foods, are an unknown and potentially damaging way to influence modern dietary habits of the general population.’ This study spawned several critical letters. It comes as no surprise that half were from people connected with the breakfast cereal industry.[vii]

The results of a very large, long-term trial, published in 1999, also suggest that, contrary to popular belief, high dietary fibre intake does not protect against colorectal cancer.[viii] Researchers at Harvard Medical School and the Dana-Farber Cancer Institute, both in Boston, Massachusetts, studied 88,757 women over 16 years. They say: ‘no significant association between fiber intake and the risk of colorectal adenoma was found’. But there was what they call an ‘unexpected’ finding, in that, according to their data, a high consumption of vegetable-derived fibre was actually ‘associated with a significant increase (35%) in the risk of colorectal cancer’. They conclude ‘Our data do not support the existence of an important protective effect of dietary fiber against colorectal cancer or adenoma’.

That fibre increased the risk of colon cancer was confirmed 6 years later by a large analysis of 17 studies of the effect of dietary fibre on colorectal cancer.[ix] Although the abstract of the study said that people with the highest intakes of fibre had a reduced risk of colon cancer, that was exactly the opposite of what the study data showed. Using the study’s Table 3, dividing the number of cases of colorectal cancer by person-years of exposure, and multiplying by 10 to obtain number of cases per 10-person-years, since the mean study length was about 10 years, the effect was not a reduction in cancers as fibre intake increased but an increase.” - Barry Groves, PhD.

I think that as long as we all practice eating REAL FOOD, and avoid all of the usual nasties (Gluten containing grains, Legumes, and Dairy), while focusing on lots of meat and some nice green cruciferous vegetables, we will all be just fine, and be nice and regular.

And that my Friends, is the paleo diet and fiber in a nut-shell.


What do you think about fiber in our diet? Is the 35 gram recommendation really necessary? Have you switched from eating a fiber diet to a low carb or Paleo diet? What has been your experience? Please share your comments below and join the discussion!

Go to, and download my 30-Day UN-Challenge eBook now……It’s a step-by-step guide to your personal health revolution.

Barry Cripps is a Paleo-based Nutrition and Wellness Consultant, who operates out of Bowling Green, Kentucky.

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