Robert Lustig says fiber is essential


Well, carbs aren’t essential for the human body, it’s a simple fact. Just because our anchestors ate everything they could, we may not find that kind of diet ideal. I would eat sugar if my survival would depend on it too but as it’s not the case, I eat better food. And that’s what matters, what is good for us, not what exactly our anchestors ate for survival.

As you and I said several times, it’s obviously individual and no woe is really good for everyone. You need your little plants, eat them, it’s fine but humans are still great omnivores who are able to survive and many even thrive without eating carbs.

(Joey) #42

Many of my known ancestors died at a young age. Doesn’t give me confidence their example ought to serve as a basis for sound lifestyle guidance.

Then again, they did live long enough to procreate :wink: … which is all it takes to extend one’s gene pool a bit longer, as far as natural selection is concerned.

(Bacon is a many-splendoured thing) #43

This lecture by Dr. Michael Eades has some insights into the proper human diet.


Lustig, “he says”, Harcombe, “she says”. I think Zoe Harcombe discusses fibre critically. But me saying that is likely confirmation bias.

Personally, I observe dietary fibre is unavoidable on a whole foods approach to eating, even in animal-based, animal foods biased, eating.

Michael has tickled a thought that I carry around, and I appreciate the opportunity to write about it. My understanding about fibre and the layering of the epithelium of the colon comes from the animal studies where the scientists examined dissected bowels microscopically. They showed that the mucus on the lining surface in fibre eating subjects was thicker. They observed the low, or non-fibre subjects had a thinner mucus layer. We could leave the observations there and note the difference.

But in the context of disease the mucus layer had to be interpreted. Fibre proponents see the less mucus in non-fibre eaters as a problem, and report the observation as a thinning while suggesting a thicker mucus layer is healthier. Denudation of the intestinal epithelium, especially when the cellular epithelium is damaged is a pathological disease concern. Rotavirus, if you have ever been trapped on a gastavaganza gastro cruise ship or bus tour, causes explosive diarrhoea due to damaging the gut lining. So, seeing thinning mucus can look scary, and by thought extension, makes thicker mucus, fibre eating seem like a healthy way.

Hmmm, mucus. If we react to a bad taste we salivate. If we breathe in a polluted atmosphere we cough up globs of gunk. Mucus is interesting stuff. It lubricates us against the toxic world. It works as a capture glue barrier that slides the danger away before it can get inside us too much. So, if we have thicker mucus on the lining of our large bowel in a higher fibre diet, might that not be a protective response? Then, if we remove the potentially injurious agent the body responds by producing the thinner protective mucus layer that is needed.

The observations are fact. The interpretations differ, or are slippery to resolve like they are covered in mucus.

Most of digestion involved with nutrition happens in the small intestine. The large bowel, into which the bulk fibre enters has added function in the removal and evacuation of toxins, water regulation, hormonal signalling in association with our gut flora, it’s the environment where most gut parasites find their most comfortable home. It’s where what we eat feeds the universe of creatures within us. The symbiosis between us all may need some fibre to make the politics work. Butyrate production is one neighbourhood.

That thought seemed a lot smaller when it was in my head. There it was just a pinpoint. I don’t think I fully expressed it yet in this first draft.

I haven’t even got to talk about fibre. My textile thoughts start like this, silk, wool, cotton, grass, bark, tendon, collagen, muscle, cellulose… Fibre that we eat is another rainbow.

Then we can talk about poo and pooing. Should we log our poo? It had to be said. No, it didn’t. I read your mind. And how after having a good poo, whatever that means, one can feel a possible mental health benefit. But the disability to have a good poo can be quite distressing. And how that has been linked in the pharmaceutical world to mobility medications and our old mate fibre.

(Michael) #45

Thanks for the links, I will add them to my growing library. They were not very convincing articles…you may like these links if you have not already seen them: high fiber makes arthritis worse high fiber does not help diverticulitus low fiber helps constipation in most people (not all) in general, fiber makes GI issues worse, not better

I think these are on-point to this discussion. Never seen a study showing fiber helps, ever. I HAVE seen lots of studies that ASSUME fiber is good and then show some effect of fiber which they conclude proves their assumption was valid. Not quite valid science in my book.

(Joey) #46

Thanks - Followed your links. Here’s how they looked to me…

#1 - Behind a paywall. Cannot access full paper.

#2 - Meaningless results. (Those with more frequent bowel movements had “higher incidence” of diverticulitis… but roughly 99% of subjects didn’t have diverticulitis anyhow). And fiber had nothing to do with it.

#3 - Makes a strong case that those suffering from constipation should cut out the fiber.

#4 - Behind a paywall - Cannot access full paper.

So #3 remains a compelling read. Will save it for future reference. Thanks!

(Megan) #47

Thanks for posting this video @FrankoBear! I needed a good laugh.


@Naghite, great post.


Hi FrankoBear, your post provides food for thought.

I watched the video of Zoe Harcombe. I had heard of her through Dr. Malcolm Kendrick’s blog and vice versa. I didn’t really find Zoe Harcombe’s lecture conclusive either way. It’s clear the goverment’s guidelines for what we should eat is just plain wrong. To even recommend eating refined grains from the supermarked’s bakery section for fiber, not to mention all those sugar-laden cereals, is not just ludicrous, but dangerous advice to the public.
What Zoe Harcombe showed of the typical fiber intake you would see in the low carb community were the sort of carbs I have and will be reinstating. But what didn’t seem very clear to me was Zoe Harcombe’s take on whether including those fiber-rich foods was essential. To me it seemed she contradicted herself, when at the end she asked the audience if fiber was essential and there was a resounding NO which she did not dispute. But why then was she showing how the low-carb society could still get fiber into their WOE?

Absolutely, eggs, meat, fish and dairy are the best foods by far, and my WOE mainly consists of these foods. I have, however, found a benefit in going from carnivore back to keto, allowing these plants that provide fibre, back into my life. As we are all so prone to confirmation bias, it is essential we listen to our own bodies. If there were studies, really strong studies indicating that all we required for our sustenance was air and food was not thought essential, would we then become converted breatharians? No. Well, I certainly hope not. So science cannot be the only thing to provide us answers. In the end only we can feel our own bodies.

(Bacon is a many-splendoured thing) #50

Don’t forget that the Dudes have two principles that they insist on: (1) Show us the science, and (2) find what works for you.

In this case, it is pretty well established that no carbohydrate is necessary to the diet, but if you find that eating carbs improves your digestion, then that is important, too. Go with what you find works best for yourself.


true but also remember we can’t compare basic science of life, like the physical body does not require 1 plant carb ever for survival…to the ‘food eaten today’ and the metabolic destruction of our bodies from that ‘food’ and then whatever life med issues have thrown on us and our med prescrips some require for true med diagnosis when we come into it so yes everyone has to do themselves, but fiber is not required by the body point blank in science…done deal…now after that life has wrecked tons of us and we see it every day. Now to do a big elimination menu like carnivore one must have longer term commitment to even see if it heals/repairs more etc but adaption/transition, based on who we are can feel very tough for many.

so it is ‘who we are right now’ but in the end, can commitment to science on real body functions and what it offers against the crap food of today and ill health that is rampant mean that if we listen to science truths and walk this path do we achieve goals that we can’t eating plants in our lives. Well ya gotta commit to carnivore to find that out, which most won’t do…they go back to plants to each issues and in the end, is it they are ‘better and healing more’ on that menu? who knows with the big shades of gray in all our lives on this day and age and our med issues?

one thing we know. no fiber in life thru the body is needed along with that carb from plants so? Start there, where it leads everyone is personal for sure.


I agree with you Fangs about us coming from different walks of life, and dealing with different issues as a result of that life. My body has been hit with a few inflammatory disorders. I have also taken long term antibiotics over the years. Not at all good for the biome.

Whether fibre is essential in a ketogenic WOE or not remains an open question. It’s an hypothesis to me rather than a fact, not set in stone as we are all so different, thus the question whether we require fibre or not, for metabolic function, for protection against free radicals, for our biome, remains open to me still.

In my case, adding back in those few carbs lifted the dreadful fatigue that had come over me. Now the reason my energy may have crashed on carnivore might just have been due to electrolyte issues, however I drank to thirst, I supplemented with magnesium and I salted my food liberally. And I was still experiencing issues which, adding back in cruciferous vegetables, solved for me. Also, I am enjoying the fact that I have more energy, am not dragging my feet after me and find myself running up the stairs again. That is not to say I didn’t enjoy the carnivore WOE and how it made me feel, and if I had more time I would have stuck with it for longer, to walk through whatever time was neccessary … For now, I eat carnivore foods on some days, and vegetables or fruit/berries on other days, so that my energy levels remain more stabile.

(Kirk Wolak) #53

YMMV… Your Mileage May Vary.

I prefer Zero Fiber, but I pay a huge price with veggies, and I love them. I don’t love the migraines I get while my body deals with them.

On the other hand, I am taking a medicine Cholestyramine (CSM) that is a binder to remove toxins. And if I don’t take some kind of fiber, it binds up my intestines. So, I’ve added a little psyllium husk fiber 30 minutes after I take the drug (3 times a day), plus other supplements.

So, I can understand there are times that fiber makes sense. In my case, to buffer my system from the toxins the binder is capturing, and to help evacuate it.

If you feel better. That’s awesome. I honestly feel better when I don’t cheat.
I feel EVEN better when I am using Caffeinated drinks… For a little while. Then I crash. Hard.
[Surpassing 600mg/day might be part of the problem] But I am honestly FLYING through my work… But at a price.

I guess that’s the point. If you can do it, and it’s good for you. Do it.
But be aware that simply “feeling better” in the short term might be masking a problem.
And if you crash after a period of time… Then there might be a lesson in there…


“Listening”, I think, to one’s own body can be fraught if one has not tuned in to the correct channel. Pavlov showed us how susceptible mammals including people are to eating cues. Many of which are not hunger cues. Cravings are the cues that can lead us to ill health. So, tuning in on healthy eating is important. Which you have done.

Zoe Harcombe is not contradicting herself. Nutrition is not perfect. Each food stuff can be a combination of essential and non-essential nutrients. In eating for the essential, we still consume that what is not required. If that is an energy providing food, carbohydrates or fat, we will store the excess for when it is needed, Or, in eating for an aim, eating on a plan, such as lowering carbohydrate, that results in a diversity of food that also contains fibre. I’m saying avoiding fibre and carbohydrates, to me, appears impossible in a contemporary normative dietary western culture.

The essentiality of fibre depends on one’s goals. As the fibre inessential to the human, may yet be essential to the kind of internal garden one wishes to cultivate.

(Alec) #55

I know what happened to me: as soon as I stopped eating plants (and therefore fibre), as if by magic my body started healing itself, losing excess bodyfat, and performing at an increasingly improved level.

For me personally it is a very very clear outcome. Plants/fibre = bad.


As a provocative generalisation, just because some information is new, doesn’t mean it obliterates the information before it. It can be so individually exciting, like finding low carb eating, that it is very tempting to bath, water, and baby, throw. Humans seek novelty, and ‘discoveries’ are presented as the ‘new thing’ to grab attention and exploit the human novelty seeking psychological trait. Often, and also, we join a trend, or join a community thought process at different entry points. So, new information may appear as a nuanced reiteration for some, let’s call them old-timers, or it may be exciting novelty for others on the path to new self discoveries.

That is a set up for presenting a 2018 video that holds some fundamental facts. My bias is toward the presenter, Dr. Paul Mason from Sydney, Australia. He takes us in amongst the weeds of fibre to contrast and compare against the fibre ‘essential’ information.


I dived into Robert Lustig’s blog to have a look for the fiber is essential information.

There is this information from March 2021 in regards to the context of fiber.

But reducing harm may be a bit easier. To help sick people get better, I’ve teamed up with a group of materials science engineers to develop a proprietary fiber that will absorb sugars in the intestine, thus protecting the liver and feeding the gut, thus mitigating some of the toxic effects of processed food. The company is called BioLumen Technologies. It is very exciting and has generated interest within the processed food industry, most recently PepsiCo.

I think I heard Dr. Jason Fung, and it has probably been written in other comments, say that if you eat the toxin (processed carbohydrates), then you need the antidote (dietary fibre). Further contextualising that eating wholefoods have the dose-dependent potential toxin and the antidote, fibre, put together in the food source, e.g. fruit.

I didn’t find the direct link to:

But will take that as the synthesis of the reading.


Hi FrankoBear, thank you for the link to Dr. Paul Mason’s lecture regarding fiber. I am still torn, however. As although I do just fine eating carnivore foods the whole week, constipation does come my way, and how I solve it is I eat some vegetables, lightly steamed, and berries over the weekend. And this always appears to solve the issue. I stick to these non animal foods for the weekend in addition to the animal foods: broccoli, green beans, blueberries or raspberries. But the amount I require is only very small, like 5 raspberries or blueberries, 3-4 small broccoli florets and 3-4 green beans. It’s how I’ve been solving the constipation issue that crops up so far, even though I know my body is quite happy on carnivore.

My other concern is, as you say whether some plants, might be beneficial for our microbiome diversity, and that cutting them out will kill off the enzymes or bacteria to digest them. This is still something I’m trying to learn about.

I had a third experimental idea and subsequent experimental approach: which was to either reduce or give up my beloved dairy, or, as I have chosen, to swap cows cheese for goats cheese, which I only did yesterday, so we’ll see how that goes, and swap my heavy whipping cream or double cream as we say, for raw milk. As I am fortunate enough that a local farmer in my village sells it. It is my hope that switching to goats cheese and raw milk will fix not just those constipation issues I’ve been having, but also address the rest of inflammation in my body which presents itself with roseaca, joint and bone aches, tooth sensitivity (despite my dentist finding nothing wrong). And if my roseaca from this goes away, my next stop will be to quit the antibiotics I’ve been on, and try and restore my biome. I have also made the switch from regular butter to KerryGold, but I’m actually not that fond of butter unless I cook with it, and it seems a waste to do that with KerryGold.

The more I read about our biome the more I am torn regarding a complete elimination WOE, as some suggest it is possible to kill off the enzymes or bacteria that allows us to digest these foods. So rather, to my mind, than eliminating foods, it makes sense to me to try and restore my gut health, through (obviously) weaning myself off antibiotics. So I might for some time stay carnivore/ketowore through the week, and eat my berries and vegetables over the weekend. My goal, however, is not to be a long term carnivore, but to eat in such a manner that I may be able to eliminate all inflammation in my body. I know my body would very quickly show me this through those aches and my roseaca disappearing.

If our skin is a compass to our health, mine is really not showing me good things at the moment. I believe this might be a combination of the long term antibiotics I’ve been taking over nearly the last couple decades for my roseaca, and my gluten sensitivity that quite possibly was what started me down the path of roseaca. But these antibiotics will likely have greatly impacted my biome and, I’m sure, continues to do so now, causing food sensitivities that might or might not go away in time once I wean myself off the antibiotics.

Now, if drinking raw milk and eating goats cheese could also allow me to stop taking antibiotics, then I might not see carnivore as a WOE as necessary, for me. I don’t call myself a carnivore but a ketowore, and I would experiment further then with what I would be able to incorporate into my WOE, such as berries and vegetables. One thing we all agree on universally I’m sure is that all processed food and sugar is an absolute NO, if one wants to eliminate inflammation. And my body is both happy and content on a ketogenic WOE, it really doesn’t need a lot of carbs, so whether one calls it keto, ketowore or carnivore, to me the body’s positive feedback about it is what makes the WOE sustainable.

(Bacon is a many-splendoured thing) #59

My skin is in great condition, so long as I keep carb intake sufficiently low. If my face and hair start to feel greasy and itchy again, and especially if I start to see pimples and blackheads, then I know my carb intake has been too high, even if it’s been low enough to keep me in ketosis.

I also have an eczema-like condition on the backs of my hands in the winter-time. It hardly troubles me on keto, and if I keep my carbs really low, then it doesn’t even appear. This year, I’ve been overindulging a bit, so it eventually showed up about three weeks ago. But usually it starts in October, as soon as the temperature and humidity drop, so I’ll take February! And of course my inflamed joints (especially my knees) and my general creakiness in the mornings go away when I avoid carbohydrate.

Many other forum members have similar stories to tell. So I’d say your chances of seeing big improvements on low or no carbohydrate are very good.

(Chuck) #60

@PaulL I am with you as long as I keep my carb intake low my skin is much better, and so are my eyes. My eyes aren’t as dry and my skin isn’t itching. I was getting areas breaking out like a rash before I went on low carbs, now the rash is completely gone. I also had a big toe with a fungus and it is clearing up too.