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. Hi Peter,
    I am posting this comment here because I believe this is related to fat consumption and after perusing a bit thought it the mos appropriate forum. I have recently discovered your blog and feel very fortunate to have done so. I’ve read through a great deal of your content, though I do have much more to read and look forward to it! I have converted my way of eating (to LCHF) and, rather than have a large proportion of protein in comparison to fat (as I’ve done in the past) I’ve adopted your suggestions and have been consuming a lot more fat in my diet (namely bacon fat, coconut oil, full-fat cream, avocado, cheeses, MCT oil etc). I am on about day 6 or 7 and noticed that this evening I’ve felt overheated, almost like I’m burning up a bit – comparable actually to how one might feel after hiking in the sun all day and getting a little too much sun exposure. I am assuming this is due to thermogenesis. Have you covered this on your blog? I did a search and found little in regards to it (unless I missed it, and in that case, my apologies). Have you had personal experience with this or have heard about other situations like this?

    I’d be most appreciative if you can shed some light on why I feel so hot! I’m considering myself fortunate in that I’m thinking it’s thermogenesis. Hope this is the case.

    Thanks for all the time and thought you’ve put into your blog. I think that it’s going to be quite a while before people start to wake up and realize what’s going on. This wouldn’t happen if it weren’t for individuals like you who, not only woke up but, took the time and concern to share their knowledge.

  2. I have a hypothesis that may seem kind of far fetched, but hear me out, even if it is a bit long winded:

    All I have is my personal anecdote, here goes: Since shifting to a Primal lifestyle, I’ve noticed I have incredible resistance to sunburns. Not just a slight increase in resistance. I went from being able to burn severely in less than an hour in UV index rating 7, to being able to be fully exposed for over 8 hours in that same UV index rating, with no ill effects. I live in Edmonton, Alberta, so we never get above UV index 7, the sun isn’t that powerful this far north.

    Can an as yet unidentified cholesterol metabolic issues (non-optimal hdl/ldl ratio, insufficiancies, etc) leave no safe avenue for UV radiation to react with, so instead of reacting with cholesterol as intended, forming vitamin D, that UV energy is transferred to normally non-reactive cellular apparatus, (ie: DNA,) causing conditions that can lead to cancerous/precancerous epidermal events? If this is the case, is a “optimal” (as determined by the first part of the hypothesis) cholesterol panel an effective means of skin cancer prevention when compared to SPF 30 sunscreen lotions, applied as directed?

    Basically, a test of one of the laws of physics, that energy can neither be created or destroyed, only transferred, and determining if that transfer, in the absence of a properly functioning cholesterol metabolism, can result in skin cancer.

    I’m not a scientist, nor do I have a scientific background, so I am in no place to do anything but think critically and ask (hopefully intelligent) questions. Nor do I know if this is science that has already been carried out. Again, no science background, can’t read a journal to save my life.

    Is this a valid hypothesis (are there others with the same anecdotal experiences, with cholesterol panel histories to back it up) or is my experience just a statistical aberration? If this is a valid hypothesis, is this something that NuSI would be interested in delving into?

    • Hi Keefe,
      Your hypothesis is very interesting!
      I have very fair Irish skin and have always burned easily. Once in midsummer I got a deep red, painful sunburn on my shoulders after less than 15 minutes of exposure (that was how long it took me to realize I’d forgotten to put sunscreen on my shoulders). At that time I had vitamin D deficiency (finally it got back to normal after 4 years of supplementing). Very recently (about the last 8 months) I’ve been eating primally and I did notice that this summer I never got a sunburn. I usually slather on sunscreen thickly, but in the summers before this I’ve always gotten the occasional burn from not reapplying often enough, and this summer none. In fact for most of August I got lax about applying it and sometimes went out without any but didn’t burn. So, I think you may be on to something. And your hypothesis is really interesting. I would have guessed, if it had to do anything with diet, that it was because of better antioxidant status from eating very well, but your hypothesis would explain it much better.

    • Interesting hypothesis. Since I’ve been supplementing vitamin D, bringing mine up from a low of 14 to a more acceptable 55, I’ve noticed a lot less tendency to sunburn. As a fair-skinned woman, I used to avoid the sun as much as possible to prevent the inevitable sunburn and skin damage; but I now take regular walks at lunchtime with my arms bared to the sun. I no longer burn and peel like I used to after even a brief sun exposure.

      I have also wondered about the relationship between sunlight, cholesterol, and vitamin D. But my question was along different lines. To wit: if our bodies use sunlight to convert cholesterol into vitamin D, does a lack of sunlight encourage the production of more cholesterol in an attempt to increase our level of vitamin D?

    • Hi,

      In my reading cholesterol and vitamin D are very similar in structure, and it is said we make Vitamin D(actually a hormone) from the cholesterol in our skin. Perhaps being in the sun lowers our cholesterol. At any rate, I have fair skin and after greatly increasing my foods with cholesterol, I do not burn as quickly. I am going out in the sun now much longer without sunscreen, and consider the sun very healing.



  3. Peter – I LOVE your blog, so a big thank you. After finding my cholesterol was over 300, I asked a friend for some tips on lowering cholesterol, she referred me here, and I’m about three weeks into my ketogenic diet and I’m sooo happy! (203 lbs to 179 lbs!!!) I have a TON of questions, but I’ll limit it to two main things. I’ve tried to do my due diligence and searched through the blog for these answers with no result, so forgive me if they’ve already been answered 🙂

    1) I’ve been doing the BeachBody Insanity workout w/ great results. I have 2 more weeks, but will continue to do it for another month after. They promote their recovery formula, which I’ve used, and it’s great as far as muscle fatigue but it’s 40g carbs! I’ve eliminated that and replaced it with a drink of 0 carb and about 8g of BCAAs, and this hasn’t been as effective in helping the recovery. A different blog I ran across: https://www.4hourlife.com/2011/06/01/targeted-ketogenesis-exercise-and-the-4-hour-body-slow-carb-diet/
    is run by a PA who advocates a ketogenic diet and Tim Ferris’ 4 hr. system. He discussed how the glucose after the workout is important with a high intensity workout, and a large amount of carbs associated with the workout is okay and won’t knock you out of ketosis. My question is basically if you would agree with that, your thoughts on a recovery drink, it’s components, how important is glucose for this phase? Any thought would be appreciated!

    2) This is piggybacking on this blog post (the last one was more of the 9 part cholesterol). My girlfriend & her mom are both RNs and very fit & healthy, and they are FREAKING out about my diet! I can’t eat anything when we go to her mom’s house because she’s so intent on the traditional no/low fat, no red meat, no egg yolks, lots of “complex” carbs, etc. uggghhh She literally thinks I’ve signed my death certificate!!! I’ve tried to gently steer them to your blog and other studies I’ve found or ask them how they know what they know, but they just won’t take the time to educate themselves and just say “I’m a nurse and I talk to doctors all day, blah blah blah”. Any advice on how to show them what I’ve learned? BTW – they just think it’s Atkin’s diet all over and don’t see a difference regardless of what I say. “It’s just another fad diet . . .”

    Oh – and congrats on NuSI!!!!

    • To your first question, BCAA and glutamine are probably good supplement during and after resistance workouts, respectively. To your second question, ask them what evidence THEY site to support their point…This post gives you plenty to talk about.

  4. Dr. Attia,

    I’ve read this post on skimmed the four about cholesterol but I can’t seem to find a definitive answer to my question.
    From what I’ve read other places, after consuming fat the level of triglycerides in the blood rises which should make the liver insulin resistant. Especially saturated fat should make the liver insulin resistant.

    How does this fit into the thinking of consuming a large portion of your daily calories as fat? I mean is there a long term risk of becoming insulin resistant due to eating animal fat, butter, cheese etc.?

    Thank you.

    • The data suggest the opposite, actually, for most people. Dietary fat does not increase steady-state TG levels. What happens on a minute-by-minute basis may vary, but most well-conducted clinical trials actually show that removal of carbs, especially sugars and simple ones, is the most efficacious way to reduce TG. Mine fell by 5x (about 150 to 30) with the removal of carbs and addition of fat. Remember: you are not what you eat; you are what your body chooses to do with what you eat.

  5. Your slide presentation confirmed my experience. I am 65 years old, and here is a data point that seems to track very well with the study results presented and your interpretation. Two years ago my cholesterol breakdown was HDL/Tg/LDL – 74/144/135. My doctor was pressuring me to take statins and monitor my liver function. He recommended the low fat, no fat, whole grain fruit – veggy, low cholesterol diet. I did this for one year. I gained five pounds to put me at the upper end of my BMI range, but not obese. The result was HDL/Tg/LDL- 71/138/138. My exercise was constant, walk 3 miles per day, lift weights every other day, ride a bike 50-70 miles every ten days.

    I ignored my doctor and the boilerplate nutritional advice offered by my HMO and decided to do the polar opposite. I went from a no-fat, very high carbohydrate diet to a low carbohydrate diet; I counted carbs and restricted myself to less than 125g per day, which I have come to realize is really not too extreme. I made a point to eat plenty of fat and protein in the form of meat as well as fish. I started taking coconut oil as a small supplement. I slowly lost 14 pounds over six months – I did not count calories, only carbs. My weight stabilized at a BMI slightly less than the mean value recommended for my height and sex. The cholesterol went to HDL/Tg/LDL – 96/79/127.

    Is this a healthier cholesterol profile? I don’t know, but my doctor, although being alarmed at my approach, said he would have to go with the numbers. I cannot ever remember an HDL number that high. My fasting blood sugar was 95, unchanged in all of this. I do not have high blood pressure.

    If it was not for the web and access to a variety of different opinions I would be on statins right now and at least 14 pounds heavier.

    • Thanks for your comments, Samuel. If I could just understand one thing, it would be this: for what % of the population is the experience you just described the expected one? Is it 50%? 75%? More? Less?

  6. I’m trying to assimilate as much as I can of your excellent cholesterol series – but still stuck on – HDL particles are much smaller than small LDL, so why are they not seen penetrating arterial walls even more readily than LDL ? It seems to me a weak idea that penetration occurs just because LDL particles are small, I mean they are naturally occurring at some concentration, even if normal may not be well established. I have to wonder if there is not an initiating injury or insult that is opening the door for these, or they are in fact supposed to enter, but the injury repair process is dysfunctional, so they continue building, etc. What if an arterial epithelial cell can’t make cholesterol quickly enough for timely repair, so it “calls for” additional cholestererol resources from the blood. But then something goes wrong…
    Second, after 1 yr on LCHF, I seem to have OK blood work (TG 0.64, HDL-C 2.4 mmol/L) , except for LDL-C of 6.9 mmol/L (267 mg/dL). I will get the LDL-P number done for sure, but I’ve no reason to believe I fall into a discordance pattern such that LDL-C number is an overestimate by factor of two or more…. any thoughts ?

    • They do penetrate. The difference is that they do not get oxidized when they are there and do no elicit an immune response, likely because they don’t carry apoB n their surface.

  7. Good Eve! I have been low carb for over 2 years with a few slip ups. I went from 148 to 118 in a 4 month period on a 40C/40P/20F ratio. I have maintained this for just over 2 years. I have been reading quite a bit about the LCHF method and really feel it is the way to go..However, like many I just can’t get over the fact that the fat isn’t causing any damage…I know this is from many years of hearing “cut fat, lower fat”. I just started this weekend and have lowered my carbs from between 90-150 to about 50ish and have increased my fat by double 120ish. I am still working on the protein fat ratio (again I think it is actually a mental block not allowing this :0). I am going this week for a staring point for my labs. My last one in July was great. So I am curious how this one will be as well as one 6 months from now.

    So my questions for you are…
    my info:I am femail, 5ft, 44 and currently 120. I am active (I climb a local mtn 4-5/wk, climb a loacl set of stairs 1-3/wk, and a 4mph walk 1-2/wk. I normally do something every day with an occasional break. I eat very healthy (with the exception of nuts, can’t get enough nuts). I have been caught up in the eat your grains hype…was so hard to give up my daily unsweetened oatmeal with blueberries.
    -How do I get past the fat conspiracy?
    -Do the calories have anything to do with entering ketosisi or is it only about the carbs?
    I am tying to loose that last 6-8 lbs but am totally stuck (which started my research on the LCHF, paleo, etc methods).

    I think that is all the info you need but I really want to enter ketosis and get rid of this last few lbs. I also want to continue the lchf lifestyle once the weight is gone. It really works for me and so far I feel great, except I find myself pinching my fat making sure nothing new is sneaking up on me :0)

    One other Q, I can not find the DEXA scan at SDSU anywher. Can you update that link?

    Thank you so much!! I love your blog, the info you offer, your journey and your inspiration and support.

    • Wait until I finish the ketosis series before you decide you want to do it. Ketosis does not guarantee fat loss. The SDSU site is called COHP. If you google some combination of SDSU DEXA and COHP you’ll find it.

    • Thank you!! But do you still reccomend the LCHF way of eating (for non ketosis) or is that only for ketosis? Sorry I have read all of your posts but I kind of got lost at one point. :0) Thanks again for your help!

  8. Brilliant! At first I wasn’t sure I’d learning anything new (I do an inordinate amount of studying) but that I can ignore LDL is a big one (though mine is low) and that regular cholesterol numbs tell you nothing, a bigy too. My HDL is 4.4 mmol/L – don’t know US measure – triglycerides 0.9 mmil/L. I do a Ketogenic raw Paleo moderate protein, low carb diet, which I suspect, is the diet Ansel ate when not being observed. 🙂 He lived to 100- where is the justice?
    Science is scary as I suspect even scientists don’t understand the scientific method when their jobs and reputation among their peers are at stake.
    My younger brother has just had a heart attack and has diabetes and follows his doctors orders to the T, always. It is distressing when the answer falls on deaf ears.

  9. Peter,

    I’m extremely interested to hear your take on the latest studies about carnatine in red meat and pork being a key factor in endothelial vascular damage via metabolism by our gut bacteria.

    I find it interesting in that it supports the idea that saturated fats and cholesterol are ok as you and others have been saying, but still suggests that red meat, though not beef fat, is something to be avoided.

  10. I did not know about your site or adventure until this month, May 2013. My question is about following this food intake approach without a gallbladder and with psoriatic arthritis. I know plenty of people in my situation. In April 2010 I went cold turkey off all wheat and grain, primarily I had done lots of research about my joint pain, joint swelling and weight gain and was very sure I had psoriatic arthritis (confirmed by a rheumatologist a month later). So I took myself off all grain based food as well as all foods containing gluten. Meats, a little veggies, lots of cheese and dairy. By mid fall 2010 I had lost 20lbs, joint pain gone and no meds. My rheumatologist was astonished. She still is to this day. I thought I had found my food balance which very much mirrored your approach.

    I kept the weight off until 2012. Then it started creeping back up and I gained 25 lbs and was sick after most meals. By June I was in the emergency room having my gall bladder removed. Ok, the thing was now I had to lower the fat in my diet after the operation because my surgeon said I would not be able to process fat as well. I couldn’t eat wheat or gluten for sure. What was I going to eat? I lost 30 lbs and kept it off for 8 months after the surgery. Started eating rice, non gluten grains, chicken and lots of fish and more foods with sugar. The weight has all returned. Mind you I am 5’8 and usually weigh about 162, but now at 180 and 47 year old female.

    Any advice to follow this meal plan without a gall bladder and with autoimmune issues?

    • Take a look at the book by Volek and Phinney, “The Art and Science of Low Carbohydrate Living.” They peripherally address this issue. Not having a gallbladder does not prevent you from making bile (necessary to digest fat), it only suggests you may want to consume them in a more spread out fashion over the day.

    • Peter, thanks for your quick reply. I am an avid reader and researcher and appreciate the book referral. – Dawn

  11. Your talk was very thorough and engaging. You have certainly given me much to think about. I have recently adopted a vegan diet but rather than mindlessly advocate for one lifestyle over another, I’ve begun a research project to try to understand all sides of the argument. I’ve come across very compelling research to adopt a whole foods, plant based diet (e.g. THe China Study and others) but I am very much looking forward to the studies you mentioned as well as watching Christopher Gardner’s YouTube video.

  12. Hey Peter I was just wondering if you have seen the study performed on mice that were genetically modified to change which cells were affected by insulin? It is is well known that a calorie restricted diet will prolong the life of most organisms but the mice who were genetically tampered with (insulin receptors in fat cells were knocked out) lived 18% longer, they weren’t calorie restricted and they also showed less signs of ageing.

  13. Over the last two years, I’ve been an enthusiastic adherent to a low-carb, high-fat (quasi-paleo, quasi-ketogenic) diet and have been very impressed with the results. Early 40s male and feel better than I have in over 20 years. I’ve lost over 25 lbs, feel great, diminished hunger cravings, increased endurance etc. Based on your extremely informative blog posts on cholesterol, I insisted that my general practioner order a NMR lipid profile rather than the standard cholesterol test during my most recent phsyical. Results were, to put it mildly, somewhat disconcerting: LDL-P at 2236; Triglycerides at 61; HDL-P at 26.2 and small LDL-P at 112 (LDL size at 22.1) (overall cholesterol at 267, LDL cholesterol at 200 and HDL cholesterol at 55). I take some comfort from my triglyceride, HDL cholesterol number and small LDL-particle number, but – taking your admonishment to heart that LDL-P is the most important number – I am concerned about my results. I know there is some disagreement / controversy on whether small LDL-P is really the number to focus on (i.e., large, fluffy LDL particles pose little risk of peneterating the arterial wall). I know from perusing the Web that this is not an isolated reaction to a low-carb, high-fat diet. Any thoughts or recommendations? Or ideas as to what might be driving the high LDL-P number? Might be worth a future blog post! Thanks for everything you do – your blog post is awesome!

  14. Hi Peter,

    I read this article today, in that lowering cholesterol interferes with weight loss, and the burning of carbohydrates(basically damaging the mitochondria).


    As a side point, I looked up John Thyfault, and he was one of the authors of a study shown here. Were you able to read that study, and did he end up saying people have diabetes from sitting in a chair?



    Thanks for all you do.

  15. Hi Peter – thanks for your postings and talks – especially thank you for avoiding as much hype as you do. I am still wading through the information you provide, having started LCHF about 7 months ago. I too look forward to part X of the ‘Straight Dope…’ and the next posting on ketosis. And if you talk about why the cholesterol numbers go up for so many people (mine too) that would be good to read.

    Here is a thought:

    in the current environment of ‘Crowd-sourcing’ perhaps NuSI would be interested in collecting, collating and analysing the information from people who could give information on diet and their lipid profile.

  16. The LCHF diet is driving my cardiologist bananas. He has basically said go away till you have your heart attack. I am a Wolfe Parkinson White ablatee, and n of 1. I found that when (post ablation and pre ablation) I exercised and my heart rate went up, arrhythmia occurred, preventricle and preatrial contractions. I would then have shortness of breath and several other cardiac symptoms. On the low carb diet I do not have arrhythmias. I use an r-r heart monitor to figure out if I am having arrhythmias. I feel incredible – now I can go on 12 mile hikes above 11,000 ft and feel great (I live in CO). The experiment is repeatable – go home at Christmas time eat carbs, arrhythmias return when I exercise. Have biscuits and gravy for breakfast – can’t exercise or hike.

    I have genetic “high” LDL’s, “high” total cholesterol, “high” HDL’s via standard lipid measurements. As a geophysicist, I knew what an NMR was and I know that cholesterol is a volume test. Since the research is implying that small LDL’s are problematic and big ones are not, I had the measurement of cholesterol by NMR done. I found that I have high LDL’s but very low small LDL’s. Plus my high LDL’s are not as high as the LDL C would imply – the total volume of LDL is high cause the particles are big not small. My doc wants me on a statin and low fat diet. I want to stay on LCHF eating – we have parted ways.

    Since I have several friends with cardiovascular disease and we all exercise at higher levels (not marathoners – ski patrollers) who have “good” cholesterol levels and have had heart attacks or multiple artery bypass; I do not feel that LDL C or HDL C alone are good measures. I think you need to have a correlative test of cholesterol by NMR to determine your risk. Is this your experience?

    The lab that does cholesterol by NMR also calculates an insulin resistance versus insulin sensitivity measure from the lipid results. There is no direct measure of glucose or insulin in the test. Is it your impression that insulin sensitivity/resistance could be reflected in the lipid profile?

    I have 9 months of excel spread sheets with nearly everything I ate in grams, with the breakdown of fat, protein, carb, fiber, cholesterol and Na grams, and liquids. My doctor was impressed with the accuracy but not the 80% fat diet. 3 cholesterol tests – one after 10 g or less saturated fat per day, one after 20 g or less saturated fat per day, one after over 20 g saturated fat per day and the NMR cholesterol after the >20g sat fat.
    In general Triglycerides go down with higher saturated fat, HDL’s go up with higher saturated fat, around 20 – 30g being my required amount (feet are warm at night when I eat more than 10g saturated fat).

    Are you interested in an n of 1, doing LCHF because of electrical issues? There is also an electrolyte component to stabilizing the arrhythmias but it is minimal. I can be very low on Mg, K or Na, if I am ketotic then I do not have arrhythmias – just feel poorly.

  17. Hi Peter,
    Thank you for this very insightful presentation. I completely agree with the thinking (and have adopted your dietary suggestions for my whole family for the past 1 year) but wanted to get your advice regarding the need of cholesterol-lowering, blood-thinning, and blood pressure lowering drugs after angioplasty surgery. Conventional doctors strongly urge the need of these drugs otherwise the arteries could be easily clogged near the stents. Do you agree with the need of these drugs given the circumstances?

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