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. Doc, I was trying to find a good place to post my questions/comments so I think this is as good as any:

    I went through your site and didn’t find much on the topic of inflammation. A lot of experts and doctors who “get it” speak about reducing it, which “feels” like the way to go, but I think there is a lack of practical advice about some very basic items for us Average Joes regarding the topic:

    What in your opinion is a solid comprehensive definition of inflammation?
    What are the most common forms of inflammation among us struggling Avg Joes?
    How do you know if you’re systemically inflamed? What are the signs? Can you specifically test for it?
    What can be done to specifically target and/or reduce inflammation?

    Like I said, I’m on board with the concept, but we need you guys to break it down so we know better what it means, how we know we have it and how it specifically relates to diet. I’m sure it’s a complicated, not fully understood topic so far but any more insight you can share?

  2. I came across your RadioLab randomly and was very interested, because for about two years I had already been on a high-fat, low-carb, no-sugar diet. After becoming enthralled in the topic and reading your blog often, I ironically was diagnosed with hypobetalipoproteinemia (my LDL is 17). I looked back at previous cholesterol tests and the one I took when I was a vegetarian/mostly vegan had my LDL at 47. How does that make sense? p.s. I am kind of freaking out because the doctors in KC espouse “the lower the better,” without taking into consideration how low LDL is linked to pre-term birth, suicide rates, and neurological disease. It is seriously annoying.

    • Kristen, it’s hard to really draw great conclusions from a lot of these data because they are very observational, as you know. Also, don’t forget that lower LDL-C and LDL-P are not the same thing.

  3. I just got around to viewing your presentation, Peter. Great summary of where we are and how we got here. I’m visiting family in Greece and just yesterday I fell into the trap of getting into the argument “saturated fat=bad”.
    Anyway…I think you know you have a long way to go. These myths and half-truths are now part of the mainstream.
    Objective researchers, such as you and Gary, are doing everyone a great service. Some of us appreciate that service right now and some will in the future.
    Great presentation!
    Keep it up.

  4. Dr Attia,

    Thanks for putting together an amazing blog and a stellar presentation. I came across your blog 2 months ago and I’ve spent every evenning reading it late into the night (mostly reading things three and four times over, as I can be a bit thick about science). Incredible. I don’t want to open a politcal can of worms, but the issue does make me think of the Keynesian Avalanche. https://www.youtube.com/watch?v=6ubTQfr_tyY

    I too have been fit and ahtletic all my life and still managed to see my weight climb to a whopping 240 lbs by last New Years (2012). At 47 yrs old and 5’11, the final straw was not being able to fit into my $1,000 GoreTex Drysuit. A ketosis based diet has been responsible for me losing 55 pounds this spring and finding your blog gives me great hope for the future. It’s great to have my Mojo back.

    Question regarding the infamous old clogged artery arguement: Would it be accurate if I were to simply say (at one of our post mountain bike ride BBQ’s) that there is more than enough L-Argenine in my bacon cheeseburger and grilled broccoli to produce Nitric Oxide to improve my blood vessel dilation and maintain healthy arteries?

    Keep up the great work. Thank you so much for your time and efforts.

    T.Low Tom

  5. It may be giving the mainstream dogma too much dignity, but I think there’s a useful analogy to the classic breakdown of the Ptolemaic earth centered model vs. the Copernican. [yea it’s only been around since the 60’s but it’s accepted so thoroughly it might as well have been around for centuries]

    The stream of newly discovered problem or protective food categories…like Fiber, Red Meat, Alcohol, Salt…are really all “epicycles”. Ptolemaic earth centered models were pretty sophisticated at predicting the movements of planets..but they had to be tweaked with new “epicycles” and exceptions quite often when they failed to predict something…so epicycles and exceptions kept accumulating for every new anomaly. Eventually the complexity became an issue in itself and set the stage for a paradigm shift to the sun centered model that could account for the facts more simply.

    When some “paradox” arrises like the fact that the french consume lots of saturated fat but have lower heart disease rates…there is a search to solve the “mystery” of how this can possibly be. It must be that drinking wine protects them! It can’t be that refined flour and sugar cause traditional societies to start getting a whole range of diseases because we know that fat is the culprit…so it must be the fiber that was taken out that really matters. Patients still get high blood pressure on a “heart healthy” low fat high carb diet…so we have to campaign to reduce the consumption of salt…cuz that’s gotta be it!

    The shocking importance of this little niche issue is illustrated by the fact that each time the mainstream invents some new little epicycle to cover some newly discovered contradiction…it sets off billions of dollars of consumption shifts and massive “education” campaigns.

    It may help to break through the clutter with some people to point out how the alternative hypothesis…kinda like the Copernican model, makes all these “paradoxes” and exceptions go away.

    • This is a great insight, Mark. Thanks for laying it out there. Important to keep this problem in perspective. I think sometimes we discount the “human” element of this dissonance because we have more technology, or better science, or more X or Y today than in the days of Copernicus.

  6. Hi from up here in Canada. This mornings Canadian news featured a report from the university of western Ontario wherein they compared egg yolks to cigarettes. Yes, cigerettes. I like eggs, and I eat them every morning; and I’m going to keep on eating them every morning.

    As a low carber, these kinds of “reports” drive me nuts. I know in my heart that if I could read the actual report, I’m sure I could find the flaws in it. However, as I can’t actually find a copy of the study, I can only go by the university’s press release.. They seem to be saying that the older you get, the more plaque one is going to get irrespective, but the cholestoral in egg yolks will make the natural accumulation faster.

    After all of my reading here and elsewhere, how in gods name did these scientists come up with this report? What are they looking at that leads them to these conclusions!! How does a working stiff with not much of a science background deal with these kinds of media reports?

    Anyway, my eggs are waiting and I’m off to breakfast. I like’m scrabbled in coconut oil.

    Here’s the link to what made headline news in Canada.


    • Dennis, the cholesterol you eat does not end up in your arteries. Observational studies do not establish causality. 2 fatal flaws in one study = should have never been published.

  7. You and Dr. Dayspring and others have said that a low carb diet improves lipids for many, but not all people. I think you estimated it at 60-70% who respond positively. We have had on this blog quite a few though, that report negative effects on their lipids. I have been wondering whether the response might be predicted by whether or not a person is insulin resistant? With the insulin resistant persons getting the positive response. So that perhaps the insulin resistance test could be used as a screen to see if the low carb diet is appropriate?

    • These exact questions are being asked in studies going on right now. While it make a few more years to find out the answers, the hypothesis that those whose atherogenic particles are part of an IR picture may be most responsive to dietary intervention is a logical one.

  8. Of course you don’t make these allegations, but there seems to be a political and financial benefit to coming to the “convenient” conclusion when reporting these government (or government grant-funded) research results.

    Secondly, the media is clearly in bed when they’re pushing the topic as hard as they can, with no more evidence than “that branch of government implied it is so”, especially when the evidence contradicts those findings.

  9. Spot on in all respects but one. I’m a living example of the fallacy that at the most 10% of dietary cholesterol is absorbed, and therefore the contribution to chol lebels is marginal. As an egg-afficianado, I went into an egg-whites only mode for several years when my chol (read LDL) zoomed, and such dietary controls plus statins and a rigorous exercise programme brought LDL down to acceptable levels. Voila! I thought I had the leeway now to try out eggs including yolks again, and lo and behold within a year my LDL was way up there again. Some googling led to views that about 1/3rd of the human population IS susceptible to hi chol absorption from food. Now, whether 1/3rd or less, I am certainly an example of the fact that SOME people at least DO absorb dietary chol. Any views?

    Now I have a question. Having accepted that chol per se is not the cause of atherosclerosis, and that it’s inflammation levels in the body which cause plaque formation, would it not still be sensible to try and limit chol levels since, without hi-chol even inflammation will not result in plaque. Seems to be much like a gun control situation with children in the house, when any accident is not directly attributable to the gun, only to the child, but then we know where that leads us. Likewise, the normal human body will, from time to time, suffer hi inflammation due to various causes, either external or personal. Does it not make sense to keep chol below levels wich will result in atherosclerosis in the event of hi-inflammation from time to time? Anything wrong with my logic?

    • No doubt. Remember, about 15% of the population actually have a “defective” ATP binding cassette G5, G8 and absorb too much FREE cholesterol. That majority of dietary cholesterol is esterified and literally unabsorbed. The important question, though, is not what happened to your LDL (I assume you’re reporting LDL-C), but what happened to your LDL-P (or apoB). Ultimately, of course, this speaks to a recurring theme on the blog…custom eating solutions are necessary for optimal health.

  10. So glad to find your blog! Even though it’s been slow going trying to convince people that low-carb is an effective and healthy lifestyle, I’ve seen the idea starting to normalize a bit more among my friends/family. All of a sudden, a bunch of people I know are on the paleo diet (which is not inherently low carb, but when you cut out processed foods and all wheat/grains, of course you will naturally reduce your carb intake), and even though many people are resistant of the idea of giving up carbs, not as many people seem to question its efficacy or call it a “fad.” Amazing how the general public seems to be getting the picture while much of the medical community is still convinced that you just need to “reduce your calorie intake and exercise” to loose weight. Truly, it’s staggering. Keep fighting the good fight! 🙂

  11. Hi Peter,

    Reading the recent obituary of diabetes and insulin pioneer Dr. George Cahill in the NY Times I came across this very succinct explanation of what you are trying to tell people about diet and insulin metabolism. The question we have to ask is, if this has been known for so long, how has the knowledge been perverted and obscured? The answer, I guess, is the idea that fat is bad and causes heart disease.

    Could the summary of this research done 50 years ago be any more plain in pointing the way to losing fat?

    ” Among his research subjects were divinity students who were paid $300 to fast for a week and hibernating bears. Some of his most important research, in the 1960s, involved tracking the blood chemistry of people who were trying out an experimental treatment for severe obesity: total starvation, for up to six weeks, in the hospital.

    A crucial finding was that in the first few days without food, the liver starts breaking down protein to make glucose to feed the brain. But using protein as fuel can be perilous, because it is the stuff of vital organs and muscle.

    But people do survive weeks of starvation. Dr. Cahill’s study helped explain why. After about a week, the body makes another shift, and instead of cannibalizing its own proteins it starts breaking down fat into substances called ketones, which can feed the brain in place of glucose. A natural drop in insulin is what drives the shift to ketones, Dr. Cahill determined. ”


    Now we know that obese patients can skip the starvation and instead initiate ketosis by limiting carbohydrates and lowering insulin levels.

    Thanks again for all your good work.

    • Yes, Dr. Cahill really seemed to understand this problem. I’ve been re-reading some of his papers later. I’m really disappointed I never got to meet him. Similarly, I’m disappoint I never got meet Ancel Keys. While I didn’t agree with about 80% of what Keys put forth, for better or worse, these men were the pioneers of our nutritional paradigm. If I could have met anyone, though, it would have been John Yudkin.

  12. Hi again.

    Well it appears that up here in Northern Ontario there is no way to get an NMR profile. My doctor tells me however that I can get an Apo-b protein test included with my blood work.

    The reason I’d like a particle count is that my LDL C in my last blood work dramatically increased after going high fat. Mind you, my triglicerides to HDL C ratio went from 1.45 to .65 so I’m pretty happy with that. Still, I’d feel better getting some hard numbers on the particles.

    So in the absence of an NMR test, is the above test still worth doing, or should I drive to Michgan (assuming I can find an NMR test there 🙂 .

    Thanks for all the work your doing here. I don’t know how many lives your changing, but you’re having a big influence for the better in our family.

    • Yes, it seems OHIP won’t send out for NMR, but if you get a proper apoB test, it’s almost as good. An remember, the person of figured out the role of apoB is at McGill!

  13. Heck, I’d have been happy to pay for it, however, the labs just don’t do them ( come to think of it that’s probably because OHIP doesn’t pay for it and there’s not enough private interest.)

    Allan Sniderman is the fellow from McGill. : I vaguely remembered that from Good Calories, Bad Calories. In fact it was that section of the book that lead me to first discuss the test with my Doctor back in march. He’s another very cool doctor. When I told him I’d been going low carb since January, he basically said ” it’s your life, live it the way it works best for you..I don’t judge.” I did not expect that response. I actually bought him a copy of Good C, Bad C. I guess I’ll find out if he read it next visit.

    One last question: the Apo-b test doesn’t tell me anything about the LDL particle subsets, only the total LDL particle count; true or false?

    Thanks again.

  14. I totally missed this post for some reason, and just left a comment on the what-your-daughter-eats post that would have been better here. It looks like my question about getting a certification in nutrition will be answered in the video.

    I liked Bastiat’s quote, but I like Mark Twain’s, too – or sometimes ascribed to James Watt:

    “A lie can travel around the world while the truth is getting its boots on.”

  15. I really enjoyed the video – or should I say “video?” I was really hoping to see YOU giving the presentation, because I imagine you being as animated and energized as you sound. I’m very surprised to read that this was your first time giving this talk. Give it a few more times and it will be killer!

    I found that I didn’t need the slides, because after obsessing about this topic for 10 years I was familiar with almost every study (and graph) you cited. I still found the talk very engaging, but it definitely needs YOU in it to go viral. IMHO.

  16. Dr Attia,

    Hi. A friend pointed me to your video, and it prompted me to do a little lit search. Are you aware of these two metanalyses?

    Jakobsen, M. U., O’Reilly, E. J., Heitmann, B. L., Pereira, M. A., Balter, K., Fraser, G. E., Goldbourt, U., et al. (2009). Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. American Journal of Clinical Nutrition, 89(5), 1425–1432.

    Hooper, L., Summerbell, C. D., Thompson, R., Sills, D., Roberts, F. G., Moore, H., & Davey Smith, G. (2011). Reduced or modified dietary fat for preventing cardiovascular disease. Cochrane Database Syst Rev, 7.

    If you’re familiar with these, what do you make of their conclusions? I’d be interested to hear your take.



    • As with all meta analyses, “good” or “bad,” they are only as good as the studies going into them. The biggest shortcoming of studies, even prospective ones looking at SFA intake, is they are difficult to control for *other* things that often track with SFA (vs. MUFA or PUFA). Chief among these, of course, is sugar and other highly refined carbs (not necessary in the same food, as in the case of ice cream, but also in parallel). So overall, I’d say these studies aren’t particularly convincing to me that SFA is “bad.” You’ll note that the AJCN article made this point, indirectly. When you sub in carbs for SFA (even at just 5%), you increase the risk of CHD, though doing the same with MUFA was not. The Cochrane study did not find a difference in overall mortality, either.

  17. Mark and Dr. Attia,
    I was not able to complete the email section required to reply to a comment above because the I could not type in the box, so I settled for putting my reply here.

    I can assure you from my education that there is dissent among the nutrition program ranks. The default answers on everything were based on the government recommendations, and while I was a student, we were only allowed to produce materials, student education etc. based on the food pyramid specifically. But, I had my core nutrition courses taught by a professor who was pro fat, along the Weston Price lines. I already agreed with this line of thinking. I knew that the problem was not fatty meat. You can imagine my surprise when on the first day, after she grilled us to see if we really knew our biology/chemistry she asked us why we thought fat was bad when it came up, as I suspect she knew it would. I had kept my tongue during my education about low fat dogma, and suddenly I had a spot of hope. I only wish I could have heard the interaction between her and the other professors, and heads of departments.

    This dissent was not limited to one professor, but the program is so competitive, if you wanted to get a spot in the program towards professional credentialing, then it everyone knew to keep their thoughts to themselves on tests and projects. I can empathize with Dr. Attia, about the pain of marking what I knew was the wrong answer to score well on an exam. I searched during my education for evidence that saturated fat was the nutritional problem it is conveyed as, and I could not find evidence. The problem is, the idea of fat is bad is so ingrained that most people assume it is unquestionable, while at the same time we are taught that we must question our assumptions and back them up with evidence.

    So please know that the nutrition/dietetics community is struggling with the same issues as the medical community, with the added burden of most physicians outranking us promote low fat.

  18. Hi Peter

    Thank you so much for your insightful website. I have had hours of enjoyment learning about the low carb lifestyle. I also purchased Gary’s book and watched a number of conferences on the topic. I’ve always felt there is so much more to the ‘energy in’ ‘energy out’ theory on weight gain and maintenance. I constantly question why some people seem naturally lean, whilst others continue to struggle with their weight, with each mouthful. It does not seem fair !

    I’ve always struggled with my own weight being nearly 11 stone at my heaviest and around 9 at my lightest. I’ve been at the lighter end for some time now but I really want a lifestyle which is not starvation and a continual struggle with cravings. I want to feel like I can comfortably be a slim person rather than battling every day! You look very healthy and lean, which is what I aim for!

    Following all this inspiration from yourself, Gary and Zoe Harcombe, Ive recently started a low carb diet. I’m eating less than about 30g a day. Plenty of meat, high fat dairy, butter, coconut oil, water and green vegetables. However I don’t feel good! I’m weak, sluggish, spaced out, feeling down and totally unmotivated to do anything. It’s really not a nice feeling ! I read that ketosis does have this effect on the body and was wondering how long it lasts or if I could do anything to reduce the symptoms?

    I’ve also come across an abundant amount of information which suggests ketosis can cause muscle loss, lead to acid in the blood which is dangerous to the kidney and bones. I’m not sure how credible this information actually is, and after reading Gary’s book, I understand how badly science can and has been interpreted. I was wondering whether you had any further insight on this or if you have any credible sources you would recommend?


    • Gemma, I am not Peter and I am certainly not an expert, but have you looked into increasing sodium (via bullion, for example), which Peter mentions in his account of similar problems with going into ketosis? This helped me. Also, Volek and Phinney in their books (recommended on this site) have some tips on mineral supplementation while in ketosis.

      I’ve found that ketosis gives me more energy, not less, but I have had to tweak it a bit, following these recommendations.

      Hope this helps you!


  19. Thank you for adding some intelligence to the topic of nutrition. I have been on the front lines for over seven years in my capacity as a health consultant working in a natural dispensary. It is extremely difficult swimming against the tide some days and there are not enough anti emetics available from the onslaught of “scientific opinion”. I don’t proclaim to know everything but my position is unique in that I see many hundreds of people and over time patterns can emerge as to what works and what doesn’t. All I’m interested in is getting at the “truth” but with so many variables I don’t think there is enough computing power on the planet to handle the job. Especially when common sense observation is neglected. Just for context, I had a massive heart attack at 36 with “normal” cholesterol levels, my doctor concluded that my test results were wrong! Fortunately a more competent doctor was able to identify iron as the culprit. I will be looking forward to more posts.

    • Yes I think I have, I could probably write a small book, it’s been over sixteen years since my attack and I have not been in better condition. I basically take the approach of treating the mitochondria since it seems to keep coming down to them. I don’t know of many disease states that don’t have some degree of defect in cellular respiration at their core. For one thing I avoid PUFA’s as much as possible especially in their denatured processed states. I’m saying this as I look out my window at the corn and soy fields the local farmers plant for animal feed. I shudder as I drive by these seemingly endless fields of corn, wheat and soy every day. Hopefully if we keep educating; the tide will eventually shift.

  20. How do you plan to deal with the idea that different individuals/genetic groups may have significantly different nutritional requirements and/or reactions? For example, an Inuit and a South Sea Islander probably wouldn’t each do well on the other’s standard diet.

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