July 17, 2012


How did we come to believe saturated fat and cholesterol are bad for us?

Read Time 2 minutes

There aren’t too many topics that really get me riled up anymore.  I’m too old and too busy to care about debating the merits of stem cell research, the legalization of marijuana, or Proposition 8.  Sure, I have strong opinions on all of these topics and more, but they are just that – opinions.  Furthermore, there are enough other people out there, some reasonable, most irrational, already fighting those fights.  So what does get me riled up?  Every time I hear someone “assert” that saturated fat and dietary cholesterol lead to heart disease I have to bite my tongue.  Why do I bite my tongue?

As Frederic Bastiat once said,

“We must admit that our opponents in this argument have a marked advantage over us.  They need only a few words to set forth a half-truth; whereas, in order to show that it is a half-truth, we have to resort to long and arid dissertations.”

This is, unfortunately, quite true.  When I’m at a dinner party and someone starts lecturing the table about the perils of saturated fat (or red meat, or eggs, or fill-in-the-blank), I’m at the point – after years of being kicked under the table by my wife – of just asking the “authority” at the table one question:  Why do you believe this is true?

I figure, put the burden of proof on them, right?  This week, and I apologize for how long overdue this post is, I’m going to get into the details of  how this country (and many others who followed our lead) came to believe one of the most pervasive myths in the entire field of nutrition.

To write it all out would require a tome.  In fact, such a tome already exists.  It’s called Good Calories, Bad Calories. But for most people, especially the “authorities” who already “know” the answer, it’s a complex and lengthy book.  Furthermore, it’s not exactly something you can just whip out at a dinner party.

I recently gave a talk at the UCSD medical school.  I was asked to give a talk about “ethics.”  While I have no professional training as an ethicist, I still think I have a good idea about what is and is not ethical.  As I’ve learned more and more about this topic, it appears to me that the state of our current nutritional environment, with food policies based on just about everything but rigorous, experimental science, couldn’t make much ethical sense.  I’m pretty sure if Plato, Aristotle, and Nietzsche were still around they’d be disgusted with how we got here.  So, I was happy to take this opportunity to speak with a group of thought leaders on this important topic.

I gave a more recent (circa 2015) talk on the subject which captures both the video and and my slides, which I’ll share below. It’s about an hour long. But as Bastiat essentially said, if you want to overturn half-truths, you can’t do it with bumper stickers. Hopefully you’ll find this talk informative and useful for your dinner party discussions.

The link to this video can also be found here, for those reading this post on email or those wishing to view it in a larger format.

Photo by Irina Blok on Unsplash

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  1. I loved this and listened to the whole thing even though I’ve read the book more than once.

    This paper is a doozy

    “In recent years, the idea that the diabetic liver may harbor a noxious brew of insulin resistance and excessive insulin sensitivity has gained a second wind.”

    Ever since I learned that livers infected with HCV (which can cause metabolic syndrome and DM2) have increased production of both glucose AND lipids, I’ve wondered, how is this possible? Doesn’t a doubling of energy substrates imply that the first law of thermodynamics, the conservation of energy, is being flouted to an extent even Dr Atkins would find outrageous?
    But with this paper, I’m getting closer to understanding the explanation.

  2. The link between inflammation and saturated fatty acids is interesting. There was an anti-low-carb article in Finnish newspaper describing the link: part of the immune system reacts to the saturated fatty acids as if they were parts of microbes and cause a constant state of inflammation in the adipose tissues. In the comments someone more knowledgeable revealed that those “saturated fats” causing inflammation have ten or less carbons. In Finnish usage “saturated fatty acids” include the short chain acids such as butyric acid, too, while English nomenclature seem to separate short chain fatty acids (SCFA) and the saturated fatty acids (SFA).

    The SCFAs are typically result of bacterial metabolism so it makes perfect sense that immune system gets activated by them. An important source of SCFAs is ruminant fat, lard and butter, which are supposed to be bad. The confusing part is that SCFAs are produced by the bacteria while they are decomposing the fiber in the gut. Fiber is supposed to be good for us, right?

    • Actually there is no evidence that fiber is good for us. The fiber story is similar to the fat story, but in reverse. I’ll detail this in another post.

    • I’ll be looking for the fiber presenation. For about 12 years or so I have to take Psyllium seed husks after dinner or the consequences are painful to say the least. I could eat a salad for breakfast lunch and dinner and there would still not be enough fiber in my system to move everything along. Keep up the great work. Hope to see the NuSi announcement soon. That and I’m waiting to see if Gary T. ever posts a comment on this blog. 🙂

  3. I haven’t found an hour yet to devote to the video, but I have read GCBC. My reaction on completing the book
    was this: Taubes convinced me that the case against cholesterol and saturated fat isn’t as certain or convincing as the medical community seems to believe. But that doesn’t immediately lead to the conclusion that consuming large amounts of saturated fat, or having elevated cholesterol is therefore safe. Saying they have not conclusively proved it dangerous is not the same thing as proving conclusively that it is benign. Maybe the real answer is: we don’t know, make your choice and be prepared to live with the consequences.

    • Actually Craig, I don’t think you have it quite right (and I know I maybe importing facts from other bloggers, such Chris Masterjohn etc, but I don’t think it contradicts anything in WWGF). Several things have no little no evidence of a association (let alone an actual causal relationship) and sometimes evidence to the contrary (i.e., an inverse correlation).
      Saturated fat intake and cholesterol levels.
      Dietary fat intake level and CHD.
      Dietary fat intake and overall mortality.
      (in other words at two(!) links in the causal chain between dietary fat and mortality don’t have evidence backing them)

      However, neither Taubes or anyone else is claiming that blood lipid profiles don’t matter. An increase of certain types of LDL species appears to be risk factor (however this very different from the what was believed before the 90’s). If am not mistaken, the association between *higher* HDL levels, triglycerides etc, is, or is becoming, fairly mainstream.

      But you are right that the data presented is not “proof”, it is more a case that (as Taubes documents) there has always been alternate hypotheses about weight, cardiac health, etc. The evidence presented is just more consistent with the alternate hypotheses rather than the conventional one, and perhaps more to the point, the evidence seems to be accumulating away from from the conventional viewpoint. But proof will only come with more data, better constructed studies, experiments, etc. In the absence of data, everyone has take responsibility for the risks of operating in a unavoidable information vacuum.

  4. Hi Peter. Very interesting talk – thanks again for putting it up for us. Can I be the lone dissenter and say that I thought the slides did not add much to your talk – or rather that you didn’t add much to the slides?

    One perspective you might think about is this: When you show a slide it doesn’t add much for you to simply read what the slide says, or to refer to it directly. When preparing slide presentations in business we were taught that we should ADD something to the slide, and that the slide should speak for itself without being read. I would eliminate the text slides which you simply read out, and replace them with more tables and data. Then while they are up you would ADD something – like an explanation of the data or another point that is not self explanatory.

    As I could not see YOU, only the slides, the action STOPPED while I listened to you read what I could read for myself. Hope you take this in the spirit in which I say it! I love your blog, and thank you so very much for all the information. You’re becoming a superstar!!! And well deserved.

    • I agree. The video would have been much better if it were a video of me giving the talk. I did think, however, this would have been better than just straight audio.

  5. Hi Peter,

    I can totally relate when it comes to having to hold back when you hear the age old sat fats are the root of all evil etc… I somehow had a mini debate with a friend’s friend on facebook of all places! She’s totally bought into the current dogma and seems to also be a fervant vegan (for moral reasons). What really got to me was that she was the one telling me that my views were dangerous and irresponsible! Rather than further getting into a war of words I made the comment that people should be free to see both sides of the coin and come up with their own conclusions. Funnily enough, her parting comment to me was that she had to no right to disabuse my ideas however if down the track I have health issues, I would be welcomed as a client (guess she’s a nutritionist or some sort of health professional). Keep up the good work! I hope one day what we know will be common and accepted knowledge.

    • Yes, I feel your pain. I know many folks who are vegan or vegetarian for moral reasons. I applaud these folks for their moral convictions. However, the only point I try to get folks to understand is that morality and science are not the same thing. Unfortunately, no area causes greater confusion on this issue that eating. Eating meat, for example, may be immoral for some. But this does not even suggest it is harmful.

  6. Peter:

    While I read your blog regularly, I’ve never heard you speak before, and found the beginning of your lecture so interesting that I have stopped listening and will wait until later today when I can collar my girlfriend into listening to the entire thing with me.

    A quick comment in the interim, though. I notice that, unlike most speakers, you have virtually no verbal “junk filler” to take up airtime, e.g., “like”, “i mean”, “you know”, etc..

    However, you do use “um” and occasionally “uh”. Yes, you speak much, much cleaner than most people who speak extemporaneously (I mean without a script), but there’s a tiny amount of room for improvement. Since you are such a high-energy and disciplined guy, may I kindly suggest that you eliminate the rest of the junk filler, as well? You’re frankly already so close, and you have such an important message, that I kind of suspect you’d enjoy cleaning up the rest of it. It could only help your credibility and message, even though from most listeners’ point of views the improvement would be subliminal.

    If you were at the end of your career, I probably wouldn’t say anything to you about it. But considering how many speeches I believe you’ll be making over the decades to come, perhaps you will ponder the advantages of speaking completely cleanly. I assure you that your audiences will find your message even more intriguing if you simply pause silently, instead of saying “um”. Audiences _love_ hearing a thoughtful person silently think between the phrases, just as music audiences love hearing the musical rests in great music.

    Anyway, please consider this unasked-for advice as if offered in a kindly way (it is!), and if you have any interest in what I’m saying, simply go back and listen intently to your speech from the beginning for a minute or two. You’ll hear what I mean.

    This is a private comment to you. While you’re welcome to post it if for some reason you wish to, there’s no need whatsoever. Thanks, and I’ll look forward to hearing your entire speech. I always enjoy being educated by you.

    Best Wishes,


    • Joe, THANK YOU so much for this feedback. While I’m naturally a strong introvert, I’m getting better at “faking” it and trying to bring energy to my speaking and public engagement. This is very helpful feedback and I’ll continue to do everything I can to improve upon this. As you can imagine, I’m an almost-pathologic perfectionist, so I won’t rest until I get it right. Please keep the feedback coming.

    • I thought that the talk was great. As someone who hates to talk in front of a conference room, let alone a conference, and has sat through thousands of talks, I would say that you are already in the 98th percentile.

      As with everything, mastery takes time, and you have to decide the priorities. I personally think that the passion that comes through offsets any (very) minor speaking issues. Like Gary Taubes, you will be in great demand soon as a speaker, so you will need to do these more often (and tape them…yes, this was a thinly veiled request for more videos…).

      I am also adding my vote to request a podcast of the Q&A, if it wouldn’t take too much time.

      • Thanks so much for the kind praise. I’d still like to hit 99.9… In retrospect, I wish we’d captured the Q&A better, as it was a great session, given the really astute audience. It was about 2 hours long, though! Hopefully next time.

    • Totally agree regarding the demand for you as a speaker!
      I will pay some good penny to hear you lecturing about the subject.
      When are you coming to New York? Tempted to meet you with a 20 pages questions… 😉

      As I said before, there’s a lot of mixed messages out there, even within the low carb/paleo community. Out of all, you (along low carb living and performance books) made things as clear as a summer day in the Israeli Negev desert !


  7. A propos of very little, but responding to Carol, who mentioned the impact of low-magnesium diets on inflammation:

    I discovered recently that unsweetened, pure (100%) cocoa is one of the most magnesium-rich food sources out there. It’s also relatively low-carb (1 gram per tablespoon).

    I’ve started adding a teaspoon of cocoa to my coffee-with-coconut oil in the morning. Along with eating almonds and soaking in magnesium salts, it’s a great way to increase magnesium levels.

    I have no idea if it’s working since I haven’t been logging things carefully, but I’m passing it along for those who agree with Carol and want to raise their magnesium levels.

    Oh, and plus… Cocoa, coconut oil, and coffee tastes GREAT! 🙂

  8. Hi Dr. Attia — FTR (for the record) I think you mis-speak at 35:32 when you say “elevated HDL was a marginal risk factor” – I think you meant to say elevated LDL. (Sorry, my OCD kicking in 🙂

    • Thanks for catching that. Yes, elevated LDL-C was noted to be a marginal risk factor, while low HDL-C was found to carry a 4x higher risk of CHD.

  9. An excellent and informative talk, Dr. Attia. I would love to hear the Q&A session even if it’s just your audio. I’m sure many others would agree with me.

    Thank you for your passionate and scientifically-sound efforts to persuade health authorities to objectively revise the accepted nutritional paradigm using the best science available – it’s desperately needed during this “diabesity” epidemic! I’m afraid that such open-mindedness can only be reliably engendered among pre-med, and maybe, very young med school students, however, who have not “bought-in” into the current model of obesity causation, treatment, and prevention.

  10. Peter, this is an email to thank you for helping me transform my cycling this summer. I first heard you on Ben Greenfield’s podcast on low carb /ketogenic and endurance sports. I listened to the podcast a few times, read your site and am so grateful for all your info and experience. I just finished my 9th Tour De Cure (the ADA aside) and did it low carb, high fat, moderate protein. I used ucan products all 7 days, climbed 30,000 feet and covered 4 states and 550 miles. I ate avocado’s every day, cream cheese when i could get it and used pocket fuel on the bike with ucan….it is amazing at 56 I had my best tour ever….thanks to you and Ben…you guys changed my perspective …and for that I owe you a debt of gratitude…keep up the good work!!!


  11. I too am a converted MD, and I have finished med school more than 25 years ago. I too used to warn patients from saturated fat, and recommend high carb diets. I now recommend low carb high fat diets and start to see some very good results. But – it isn’t easy. Many patients find it very hard not to eat bread, rice, pasta, potatoes. And others don’t believe me.

    • Mira,
      I have to ask, because your first name and age fit the description of an M.D. named Mira I have met (what are the odds?), does your last name begin with “V”? Curiosity is getting to me.

  12. Thank you very much for a wonderful site. I find your detailed discussions of scholarly articles and the changes you have experienced from being in ketosis to be the best I’ve seen on the web. It is the only site I have seen thus far that, as a fellow MD, I would recommend for someone searching for the quality of information – and explanations – they need to better understand these complex issues on their own.

    One aspect I have not seen addressed (and I may have simply overlooked it) is mineral loss in ketosis, especially sodium and calcium. I assume that with the increased losses, you supplement minerals. Is that correct? How did you estimate the required daily amount of sodium? Thanks.

    Thank you.

    • Thanks very much. Glad you find this to be a helpful resource. Lots on here about mineral and electrolyte replacement, but most throughout comments, especially under topics pertaining to ketosis. I supplement lots of sodium and magnesium. The Ca++ and K+ take care of themselves when these 2 are corrected, especially sodium.

    • Our local newspaper referenced an article apparently published in the American Journal of Physiology-Renal Physiology that concluded that ‘excess salt’ resulted in increased excretion of calcium (100 mg extra salt=1 mg extra Ca excreted), leading to potential kidney stones and osteoporosis. Study was done on mice, so a bit of an extrapolation to humans. Always hard to sort out all the conflicting information, especially with my non-medical background.

  13. Thanks for the reply. (On a lighter note, I have to add here that I am not a compulsive thanker; the third “thanks” in my original post was an editing error.) I haven’t looked through all the comments yet, but I will.

    It has been more than a decade since my med school years, but I would be shocked if the quality of nutritional education has improved much. Given the inseparability of diet and health, this seems to me to be a major failing of our medical education system. And that does not address, of course, the prevailing inaccuracies of much of what is currently taught. I know several other physicians who are, like me, attempting to fill in our knowledge gaps about these issues. It is heartening to see your site engaging in such an effort and doing it well. (Ok, maybe I am a bit of a compulsive thanker, but this is like rain in a drought.)

  14. This arrived in my order from the Vitamin Shoppe: “Food Based Packaging- The lightweight packing in your box is enviornentally friendly. Although it may look like styrofoam, it is actually made from potatoes, rice, and other natural foods and will dissolve on contact with water.” Finally a good use for the low fat, high carb diet.

  15. hi peter,

    thanks for making this talk available, really enjoyed it & have spread it far & wide.

    obviously with 90-120 min of Q & A your audience was very interested. what was the general vibe of the audience? do you feel you “won them over”? were they enthused, negative, angry….

    cheers chris

    • The audience certainly seemed interested and informed. Not sure I captured their mood upon departure other than somewhat surprised or in a state of disbelief.

  16. When tracking grams of carbs via a site like https://www.calobonga.com/, do you take the total carbs listed and subtract the total fiber (soluble and insoluble) assuming they are both non-metabolized, or can the gut flora also utilize some of this portion too through complex fermentation reactions? I’ve also seen articles inferring that some soluble fiber makes it across the gut barrier and into the circulation. Is that really true and if so how is that metabolized or excreted?

    • I don’t personally, because I like to keep it simple. I know that if I’m keeping total carbs less than 50 gm/day, and none of my carbs are “bad” ones, my net is probably half that or less.

  17. Hello Dr,

    Thank you for all of your sincere efforts. Is there any way to contact you privately?

    Thank you.

  18. Hi Peter,

    I do not feel like completely eliminating carbs would be something that would suit me, or that I could sustain in the long run. Instead, I plan to cut out all refined sugars and simple carbohydrates, and eat purely complex carbohyrdrates that are low in sugar (porridge, wholemeal etc.).

    However, If i am still eating carbs, what effect does this have on how much fat I should be eating. From what I understand, the carbs are what triggers insulin to be produced which is what puts the fat into your fat cells (thus making you gain weight). So if you are eating no carbs, then the fat will not be stored in your cells.

    If you are still eating carbs, should you start worrying again about how much fat you are taking in, as this will now be put into your cells? How much fat should one be aiming to eat daily if they are maintaining complex carbs in their diet?

    • Dave, I’m glad you’re thinking of things through the lens of long-term sustainability. If you just eliminate sugar and simple carbs, you’re going to get a huge bang for your buck. You will also require far less fat than someone in ketosis who needs to go out of their way to ingest fat. There really aren’t great data to answer the question I think you’re asking. It certainly seems that eating saturated fat + sugar is a bad combo. I have not seen any evidence, however, that eating saturated fat in the presence of “good” carbs is bad. If you think about, most of subjects the studies I presented here were not in ketosis, suggesting ketosis is a “magical” state where one is immune to the effects of saturated fat.

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