Frédéric Leroy Profile picture
Sep 5, 2018 72 tweets 23 min read Twitter logo Read on Twitter

Besides being a 'pharmakon', meat is also a 'pharmakos' (scapegoat). As the most symbolic of all foods & as a predilected carrier of meaning, it acts as an adsorbent of societal anxieties. Often presented as scientific 'truth'.


There is something seriously rotten in contemporary nutrition. The entire chain-of-proof is no longer based on the scientific method but is profoundly corrupted by vested interests and ideological dogma.

Cf. my paper on meat in the post-truth era:…

Except for the Daily Mail-like headlines, it all looks pretty convincing. The meat-is-bad narrative is now supported by official institutions such as the WHO and the AICR. Which seems to end all debate.

But wait a minute...

Let me bring up this lovely slide by @GrassBased.

... and take 4 studies arguing for plant-based diets and meat reduction (I could have taken many others, but these are quite representative)

So, let's zoom in...

First point: epidemiology and food frequency questionnaires 🤔

Basically, if one has a close look, this seems to be the foundation of most the anti-meat discourse.

Yet, they are very problematic in many ways.

We have seen an example of how unreliable FFQs are in the recent study by Seidelmann et al (Harvard, ladies & gentlemen).


Also, how can we reliably evaluate a heterogeneous category such as "processed meat" if everything is jumped together in the reports?

Next point: lifestyle patterns.

"a lifestyle pattern that includes a very low meat intake is associated with greater longevity"


If we talking about lifestyle, wouldn't it be fair to mention confounding effects within the diets of most meat eaters? Not everybody is #LCHF, #paleo or adhering to the #meatheals approach. As a matter of fact, only a minority is & I'd like to see a study on those people.

Here's another study showing just that. Also, the effects seem larger in the US than in Europe or Asia. How come? 🤔

This is what we are lookin at.

Don't blame the meat for what the bun and the soda did.


Let's move on...

"Associated with"

Again, foundational to the entire narrative. But does that even mean something?

Chocolate consumption is associated with the amount of Nobel laureates.

Meat consumption is associated with diabetes.


According to basic scientific practice, correlation does not necessarily mean causation.

Do I even have to repeat this?

In the large majority of the cases, observational claims are refuted or even contradicted by controlled intervention studies. Over and over again.

Here's an example for the case of meat and insulin dysfunction. RCT refuting epidemiology.

Risk ratios. HR or RR or OR. Whatever.

Just this showing the problem with HR, but let's not even get into that... For the sake of argument, let's ignore such statistical complexities and look at the concept of "relative risks" sensu lato.

Relative risks need to be above 2 to have some meaning, and above 5 to be taken seriously. Below 2 (which is mostly the case for the epidemiology on meat) "we are simply out of business". Read that again: "we are simply out of business".

So if we are talking about colon cancer why aren't we looking at the real issues?

A RR of 6 (visceral fat) means you've to multiply teh risk with a factor 6. Ouch.

For meat, you multiply with a number that is almost one. Multiplying a number with one gives you...?

This one is massive.

Nobody less than Guyatt & Djulbegovic, two top clinical epidemiologists, trashing the WHO for its "disservice to the public" based on GRADE criteria.

Next topic: "statistical significance"


And we really need to do something about it, because it is just generating noise.

"A statistical significant result is not necessarily clinically important".

Cochrane speaking.

Which brings it to the difference between RR and absolute risk. The latter being a much less sensational criterium to judge meaningfulness. But hardly appearing in communication (even scientific ones).

Compare the values of RR and AR for meat and colon cancer and make your conclusions about what is more meaningful (supposing this effect is real in the first place, which based on the above is very unlikely).

Here is a variant.

So what does this concept of "risk" mean? And is it applicable here?

The WHO refers to IARC. But IARC *never* mentioned risk. That is not within their mission. The only thing they do is to identify "hazards".

Hazards are *not* risks. To make the link one needs to perform a risk assessment.

They have actually also classified sunlight as a hazard. Does the IARC tell us to avoid sun? Of course not. It makes us all joyful and brings in vitamin D (to keep the analogy with meat, also bringing in plenty of essential nutrients).

So where is the risk assessment? Well, basically, it has been done. And it tells us this:

We are talking about human health, right?

So what if the data are based on animal experiments? Are they valid?

Well, they could have had some value, if their use in the entire IARC report would not have been that problematic.

I refer to this excellent analysis by @GeorgiaEdeMD:…

Couple of screenshots here.

So, even if you see RCTs, be it with animals or humans, don't just accept them as true. Have a good look: they often face a range of strong assumptions, biases and limitations. I again refer to @GeorgiaEdeMD for a critique of the human trials…

Let's move on.

"Overall, it is plausible to conclude"

These kind of sentences make me feel suspicious that somebody was already planning to write this exact sentence before even starting the analysis.

Enters "cherry-picking".

Why such authors never mention this kind of data?

Or this...

Maybe this? Effects on lipid markers being mostly neutral.

... or beneficial!

Reduced mortality from stroke, anyone?

Or this recent study by @andrewmente and coworkers: "Regarding meat, we found that unprocessed meat is associated with benefit."

If meat is that bad, why aren't vegetarians protected from disease then?

And if we really have to take those associational studies on top, why not mention that meat is also associated with protection against some other cancer types than CRC? Take melanoma.

Here again: positive association with colon cancer and a negative one with melanoma and leukemia. Why is nobody talking about that? Why is this not all over the news: "eating meat protects against melanoma!!"

Getting worse! What if colorectal cancer incidence would be *higher* in vegetarians than in meat eaters??

So: contradictory studies and lots of cherry-picking as a result.

The answer: meta-analysis?

Systematic reviews and meta-analyses. Is this not the best evidence we have?

It may be. Provided the studies are good. Not if it is garbage-in/garbage-out.

I just love this paper by Ioannidis.

... showing that only 3% of the meta-analyses are both decent and clinically useful.

Yep. 3%.

This is a meta-analysis. It's not part of the 3%.

And hey, this is a meta-analysis.

The difference: these ones have actually done their homework and exposed the flaws and weaknesses of the available studies.

And here is a systematic review.

"Insufficient evidence to confirm a mechanistic link"

It's also fun to see that the result of a meta-analysis depends on the inclusion of certain "atypical" studies.

For instance: the result looking at heart disease depends whether or not we consider Seventh-Day Adventists studies.

These guys... Remember the name of the author: Fraser. Come back to it in a moment.

First, to explain how the SDAs are a sectarian movement with the weirdest ideas about diet and health, look at this thread below. It also shows how ideology and vested interests go hand in hand, promoting plant-based diets.


But let me just zoom into this slide. Here is Fraser (see above), standing in front of an SDA background ("god", "redempetion", ...). Those people are bringing in the studies on plant diets. Studies that distort the overall numbers (see above).
We could talk a lot about vested interests and how that shapes the plant-based hype, but that would take us too far. Just this.

Or maybe not. Let's start from this statement. Meat harms the planet and see where it brings us...

This is what Greenpeace is doing in Belgium. Not that I am a fan of marketing (especially when kids are targeted), but this is just maddening. Implying that parents giving luncheon sausage to their kids could as well give them cigarettes.

But this is beating everything... The double food pyramid by the Barilla Center, combining health and sustainability in one model.

No conflict of interest of course. As declared.

And being widely applied and taken for granted. It was published in a scientific journal, right?

Here: doctors without borders falling for it.

Look, here is Barilla again 😀

And, hey, is that a link to Willett?

And this is the double pyramid besides the Flemish flemish food pyramid. A perfect synthesis of both barilla pyramids. And carrying the same colours as a tribute?


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More from @fleroy1974

Sep 2, 2018

L Keith, ex-vegan, talks about how her diet led to catastrophy on the long run:…

For ex-vegans on twitter with similar stories, see… - also check out @SBakerMD's #meatheals

First, let's put aside the myth that plant-based makes you healthier. Those claims are based on weak and biased epidemiological associations (RR=0.8-0.9?? - seriously, that's just meaningless).

The best plant gurus can get out of more controlled studies is the fact that it lowers total cholesterol and LDL-C. But, that's just another belief system - no point wasting time on the meat-gives-you-clogged-arteries propaganda...

Read 38 tweets
May 12, 2018
Meat: its evolution from long-established health food to poison. What happened? (Small tweetorial, illustrating the ideological coup by Seventh-day Adventists)
Read 8 tweets

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