Fibre - is it the high carb diet's last straw? Keto bashing in the mainstream. "There goes the keto diet!", predicted the celebrity doctor



Dr Norman Swan is a mainstream media health science communicator popular in Australia. He leans toward a Mediterranean diet for best human health and seems dubious about low carbohydrate ketogenic diets.

Two quotes from his commentary in this episode:

“An enormous study which might make you think twice about a low carb diet.”

The paper which is a systematic review style paper:

“There goes the keto diet!”

I won’t dig in to the scientific paper (yet). I hope someone like Dr. Zoe Harcombe or Professor Grant Schofield might have a go at that. But I’ll have a go at pointing out some highlights in the Health Report media report.

From the top:

  • “…we’ve always known that dietary fibre is protective against a number of diseases, but what we came up with really surprised us in terms of the extent to which dietary fibre is protective against so many important diseases.”(Prof. Mann).
    ** Dietary fibre in the large bowel, with the correct biome, will be broken down into short chain fatty acids, butyrate, which is anti-inflammatory. Hokey, dokey fair enough. The use of an ‘Appeal to tradition’ (argumentum ad antiquitatem) fallacy in the Professor’s opening comments alerts the reader to possible scientific mischief ahead.

  • “This was an enormous amount of data, 135 million person-years from studies that have followed people through life, and randomised trials where they are being given fibre.”(Dr. Swan)
    **I’d need to check, but the participants in the collected studies were probably from the general population eating the standard western diet. The benefits of fibre being extrapolated from a change to a poor diet. We know there is benefit to any change in the standard dietary recommendations.

  • “Dietary fibre, if one had reasonable intakes, and we came up with 25 to 29 as being the minimum ideal intake, that’s grams per day, protected against the development of colorectal cancer, that was particularly striking, and in fact it seemed that the further you went beyond 30 grams the further was the protection against colorectal cancer, protective against diabetes, protective against cardiovascular disease and reduction overall in total mortality. (Prof. Mann)
    **25g to 29g (minimum) per day of fibre from wholefood sources such as fruit, nuts, grains, legumes, seeds and vegetables carries a lot of carbohydrates with it. Remaining in nutritional ketosis may not be possible? False. The Professor is advocating for a high carb diet based on the findings and interpretations of his research.

  • The Rub. " Carbohydrates is where we get this fibre from, is your argument." (Dr. Swan)
    “Absolutely. So, even if you were having good low carbs, you are not going to achieve those intakes.” False “So I think it should make people want to think about whether there really is benefits to these low carb diets.” (Prof. Mann).
    **There we have it. Human health is fibre based, according to the 'authority’ (Prof. Mann, in this case), for any unwary listener. But his conclusion is based on a failure of truth.

  • Red meat and colorectal cancer. “That is an incredibly important point that you make, and I think applies particularly of course to colorectal cancer…” “…where there is reasonable evidence that red meat and processed meat increases the risk of colorectal cancer. And you’re of course absolutely right, that people who have a high carbohydrate, high fibre diet, of course they tend to have less red meat, and to some extent I think that may well be part of the explanation.” (Prof. Mann).
    **Not just low carb questioning, but also red meat singled out. Quacks like a vegan? We know the World Health Organisation report on red meat and colon cancer was thoroughly debunked by examining the difference between absolute risk and relative risk. And at best the non-significant result highlighted explained, if any relevance could be applied, by the healthy user bias; that being that the standard, unaware people eating red meat in a standard western diet in general society also had other “unhealthy” confounding habits (e.g. smoking). Prof. Mann is on the WHO Expert Advisory Panel on Nutrition. It was the WHO International Agency for Research on Cancer (IARC) that authored the debunked (but persistent) advisory on carcinogenicity of the consumption of red meat and processed meat.

  • Summary advice from the interview: “…that you should have some fibre from wholegrain cereals, you should have some fibre from fruit and vegetables and legumes and pulses is really probably one’s best bet.” (Prof. Mann)

I’m thinking, is it the low carb eating bashing season again? Usually it is from Harvard researchers. It looks like University of Otago is joining the band.

Too much fibre. I feel nauseous.:exploding_head: An interview media report like this creates a false authority fallacy, the single authority type, in that it uses only the single opinion of the interviewee to sell the idea presented in the information being discussed. It is up to the reader or listener to seek other points of view.

Maybe this fibre push will reduce the prices of avocados, salmon and butter?:grinning::smiley:

Your thoughts?

(Bunny) #2

Ah that’s the rub! (Shakespeare):

When you reach the end of the tangled rope being weaved that seeks to deceive their are three key players that really matter with what’s being cited above and that is advanced glycation end products they are:

  1. methylglyoxal

  2. 3-deoxyglucosone

  3. fructosamine 3-kinase (FN3K)


  1. Glutathione depletion

  2. Organic sulfur depletion

(Doug Wold) #3

Jeff Volek and Steve Phinney just discussed this very topic on the Virta blog.


Thanks @Doug1 Doug.

(Bunny) #5

Was looking at this earlier also (deeply insightful and comprehensive):

Fiber and Colon Health On A Well-Formulated Ketogenic Diet: New Insights Question Its Role As An Unconditional Requirement: “…Despite the emphasis placed on fiber as a part of a healthy diet (assuming that one is eating lots of dietary carbohydrate and thus not in nutritional ketosis), the fact remains that fiber is not an essential nutrient in its own right. From this perspective, soluble fiber plays a supporting role in colon health, but only if one has an optimized microbiome that produces butyrate. Thus, while it tends to get top billing in health promotion, since fiber primarily facilitates the production of SCFAs like butyrate, they are the real stars of the show.

Fiber is often further separated into two categories:

  1. Soluble (absorbs water, increases stool bulk, prone to fermentation)
  1. Insoluble (promotes motility, less prone to fermentation) …More

(Bunny) #6

Carbohydrate quality and human health: a series of systematic reviews and meta-analyses: “…Implementation of recommendations to increase dietary fibre intake and to replace refined grains with whole grains is expected to benefit human health. …”

“…benefit human health?..” Not by much according to Dr. Berg?

Are Whole Grains REALLY that Healthier than Refined Grains?


This is a recent talk in which this cardiologist responds to the fibre issue. It’s only a segment in the talk though.
The whole speech is worth listening to.


Keto and Metamucil (psyllium) as a daily fiber supplement?

Thanks Mito. This is awesome. Dr. Malhotra actually talks about the scientific paper that this comment thread is based on, and about Professor Mann getting his facts wrong and misleading mainstrem media about LCHF eating.

Low carb negative headline is “an example of eminence and ignorance at the highest level of academia trumping evidence and truth.”

(Chris - #9

Lol fiber has no benefits.

Everything you need fiber for (which is not digestion, by the way) is covered on a properly-implemented ketogenic diet.

Here’s some further info from @amber.

(Scott O) #10

Going Keto finally lead me to eat high fiber vegetables.

(Carl Keller) #11

I agree that fiber is very important in a diet rich in processed foods. In his book The Obesity Code, Jason Fung likens the relationship between processed foods and fiber as poison is to antidote and says that without the poison, the antidote in unnecesary.

Futhermore, he says, It is no coincidence that virtually all plant foods, in their natural, unrefined state, contain fiber. Mother Nature has pre-packaged the “antidote” with the "poison. Processed foods remove fiber for palatability and profit.

(Chris - #12

Shoot, thought I read that book and I’m hearing that from Fung’s mouth for the first time. Crazy.

(Sheila) #13

I began to doubt the great FIBER MYTH when I researched diverticulitis as it is a family issue resulting in surgery for two siblings who both subscribed to the fiber will fix it mentalality.
The treatment for diverticulitis is low fiber when you have a flare up but return to high fiber when you recover but expect a flare up and return to low fiber.
Since eating a Keto WOE I have had no problems and can’t wait until my next colonoscopy ( not really) to see if any healing has happened. It would prove that diverticulitis can be reversed if I have any improvement.
Just another case of medical professionals thinking they have the answer without the science to back it up.

(Chris - #14

Couple anecdotes regarding diverticulitis:

(Sheila) #15

DThanks, I always enjoy reading another’s stories of success with healthy eating. I wish I could help others to see the light. I donot look forward to hearing about my siblings latest bowel flare ups and surgery but they think I am crazy for eating this way. I think they are crazy for eating a diet that has always made them sick. Still love them but can’t fix them.


And less meat?

(Karen) #17

Lchf. The lc, because it’s veggies like broccoli, is going to be higher in fiber anyway, pretty much. It is for me anyway.


Link above to more fibre discussion and media reports on the same scientific paper.

Media reports in the UK were from January 2019.

It just took a bit longer for Dr. Swan to report on it in Australia.

(Omar) #19


I have diverticulitis

I posted here many times that sometimes fibers help in other times they hurt.

leafy greens are wide range of vigitables some of them hurt like kale others help like lettuce.

lettuce is much better than nuts.

(Todd Allen) #20

This won’t lower avocado prices, despite being low in sugar and starch they are high in fiber.