#DietSpeak: saturated fats – challenging the dogma


Barts-MS rose-tinted-odometer: ★★★

Since my rather neutral #DIETSPEAK: IS THERE AN IDEAL MS DIET?post last week, in which I refuse to support any particular MS diet I have had a  torrent of social media abuse about my position. Intriguingly, many people out there have bought into the falsehood that saturated fats are bad for you and some commentators even believe that saturated fats cause MS. The evidence is clearly to the contrary for the former and for the latter the evidence is just not there to draw any causal inferences. In fact, as saturated fat consumption has gone down the incidence and prevalence of MS has increased.  This alone indicates that saturated fat consumption cannot be the cause of MS.

John Maynard Keynes, the famous British economist responsible for ‘Keynesian economics’, is often quoted as saying: “When the facts change, I change my mind. What do you do, sir?”

The claim that saturated fat is bad for health was promoted by the now-discredited physiologist and nutritionist Ancel Keys.  His theory was based on his ‘Seven Countries Study’, which has now been discredited with several commentators suggesting that some of the data was made up. There is evidence that of 22 countries that he had data for, he cherry-picked 7 countries so the data would fit and prove his hypothesis. Despite this, he and his collaborators managed to change the dietary guidelines of the world, recommending a low-fat diet to counteract the cardiovascular disease epidemic. Tragically, the rest is history.

Image of Ancel Keys from ‘A decade of diet lies‘ HUFFPOST

The low-fat diet, in particular the low-saturated fat diet, resulted in a caloric switch to carbohydrates, which has seen obesity rates soar and contrary to what was expected cardiovascular disease rates have increased. It is now clear that Ancel Keys was heavily conflicted and was supported by the food industry. Yes, the food industry managed to influence a change in dietary guidelines that have killed tens of millions of people prematurely. I predict that when the dust settles on this issue the food industry will be judged to have behaved much worse than the tobacco industry. 

The good news is that the facts have changed and several recent meta-analyses have been unable to find any evidence that saturated fats are bad for you (please see review below). The studies showing saturated fats are associated with poor health outcomes are confounded by other factors for example the consumption of processed carbohydrates. 

To address the point that saturated fats cause MS you need to go back to causation theory and apply epidemiological principles. I have addressed this topic several times in the past on this blog, mainly in relation to EBV as a potential cause of MS. To prove or disprove causation you have to satisfy as many of the following nine criteria as possible. 


When you apply these nine criteria to saturated fat consumption none of them is fulfilled. I, therefore, can conclude that saturated fat consumption is not the cause of MS. On other words, the data disproves the hypothesis.

Another perspective that you can use to tackle this problem is an evolutionary medicine perspective and to look at how our ancestors evolved and what diets they ate. It is clear that our ancestor’s diets were high in saturated fats and as the history of MS suggests it is a relatively new disease it cannot be caused by saturated fat. In fact, if you want to finger a dietary factor you would point at sugar and processed carbohydrates rather than saturated fats.

I wrote a piece on Medium to explain why low-fat diets are potentially bad for you. You may find the evolutionary medicine approach to diet of interest; I think it may prove to be very relevant to MS. 

Astrup et al.  Saturated Fats and Health: A Reassessment and Proposal for Food-Based. J Am Coll Cardiol 2020 Aug 18;76(7):844-857. doi: 10.1016/j.jacc.2020.05.077. Epub 2020 Jun 17.Recommendations: JACC 

The recommendation to limit dietary saturated fatty acid (SFA) intake has persisted despite mounting evidence to the contrary. Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing SFA intake on cardiovascular disease (CVD) and total mortality, and instead found protective effects against stroke. Although SFAs increase low-density lipoprotein (LDL) cholesterol, in most individuals, this is not due to increasing levels of small, dense LDL particles, but rather larger LDL particles, which are much less strongly related to CVD risk. It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution. Whole-fat dairy, unprocessed meat, and dark chocolate are SFA-rich foods with a complex matrix that are not associated with increased risk of CVD. The totality of available evidence does not support further limiting the intake of such foods.

CoI: multiple

Twitter: @gavinGiovannoni               Medium: @gavin_24211

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.


  • typo:

    “When you apply these nine criteria to saturated fat consumption none of them is fulfilled. I, therefore, can ??? conclude that saturated fat consumption is the cause of MS. On other words, the data disproves the hypothesis.”

    I think you missed “not”.

    “I, therefore, can NOT conclude that saturated fat consumption is the cause of MS.”

    Also: is there a link between inflammatory state and saturated fat? Or is the link far stronger between inflammatory state and sugar / carbs?

  • Oh dear. I feel your pain; the pain you felt for further comment. I read your last post on diet and IF and had my interest piqued. I’m a 52 yo with an MS diagnosis for the last 20 years. It’s been RRMS and for most of the last 20 years I count myself as lucky. I’m now a full time Wheelchair user who had my second Lemtrada treatment in April 2019. Weight gain isn’t conducive to wheeling and I’m told my thyroid remains at ‘normal’ borderline levels, (so no easy get out there 😂) Thanks to your article I’m trying 5:2 IF and writing my shopping list now. I’ve been Lacto-Ovo Vegetarian since January and as the Keto recipes for LOV seem, to me, to be a bit lacking, I’m leaving the Keto switch alone for now but will revisit in a few months. Thanks for continuing to do what you do and posting the articles that you post. Much appreciated

  • The article you cite is specifically about heart disease. Could you cite an article that disproves the Swank or OMS evidence about satfat and MS? Or is it just that we can’t say definitively, within the above criteria, that satfat is a factor, so therefore it isn’t?

    • Apologies, surely the argument is the other way around. Where is the evidence that the Swank diet or OMS diet treats, prevents or cures MS 😉 It is not the MS community’s responsibility to prove that these diets are not effective, but for Swank and Jelinek to show in randomised controlled trials that are they effective.

      To quote the MouseDoctor, “eating ice cream is an effective treatment for MS, prove me wrong”.

      • Jelinek has more evidence than Swank’s observations. But only a controlled trial is persuasive? parachutes and so on. is there no room for logical inference strongr than ice cream?

        • Re: “inference stronger than ice cream?”

          That is MD’s in-joke.

          Re: Jelinek

          Unfortunately, he has no real evidence; it is all anecdotal. This is one of the reasons why I can’t support any MS-specific diet. Saying this if the Jelinek diet works for your so be it; it is horses for courses.

          • The problem is how do you conduct a randomised, blinded study asssessing diet? Jelinek may not have this data but surely observational, long term data holds some credibility? I’m not arguing for OMS and would never advocate any diet over receiving a high efficacy DMT. The problem with the OMS diet (and others) is that it is difficult to follow for many people. Dining / eating is a cultural experience and for many people with MS, central to retaining a sense of normalcy (for lack of a better word). My wife and I tried following the OMS diet when she was first diagnosed but she found it was just another reminder that she has MS. She is also a foodie and loves to cook.

            Mindfulness and meditation however, should be introduced into everyone’s daily routine. Stacks of evidence showing many benefits (not limited to MS).

    • RE: “The article you cite is specifically about heart disease…”

      Yes, that is what the saturated-fat-heart hypothesis is about. There are no national/international saturated-fat-MS guidelines to argue over.

  • Thank you for this. Please keep on fighting the good fight on the importance of good nutrition for those of us with MS. There is such a lot of nonsense out there, and your good sense is refreshing.

    • But what is “good nutrition for those of us with MS”? That’s Prof G’s point: There is no evidence that any diet is good or bad for MS. Even saturated fat is OK.

      • I am also making the point by inference that a diet that is bad for cardiovascular and cerebrovascular health is also bad for MS, because comorbidities are bad for MS. Therefore you still need to try and live a heart- and brain-healthy lifestyle. As you do that you realise that the dogma around the latter is being challenged as we speak and read.

  • Do you think omega 3 fatty acids and omega 6 fatty acids supplements are beneficial to MSers? My understanding is that they are anti inflammatory and help in regulation of insulin. Do MS brains show an imbalance of these fatty acids? What did Dr. Swank get right about fats? What about feeding the mitrochondia, as Dr. Whals prescribes?

  • There’s no distinction stated in this post between ‘good’ saturated fat and ‘bad’ saturated fat…does that categorisation not apply to saturated fat then?

    ‘… It is clear that our ancestor’s diets were high in saturated fats and as the history of MS suggests it is a relatively new disease it cannot be caused by saturated fat.’ –
    could it not be argued that MS DID exist, it just wasn’t recognised as such and killed off those that had it anyway?

  • I have to come clean from the beginning here – I do have a bias in that I follow the OMS program, and watch my saturated fat intake. However, I not taken Dr Jelinek’s book at face value, and have been doing my own research into the subject.

    It is wrong to say that the OMS program focuses on saturated fat intake. I actually see the focus more as redressing the balance of the Omega 3 to Omega 6 in our diets. Ideally the Omega 3 to Omega 6 ratio is meant to be around 1:3/4, but in the West on average the ratio is more around 1:15. possibly in some people more around the 1:50 mark.

    People like to reference how our ancestors ate plenty of saturated fats in their diets, but the nutrient profile of the foods they were consuming were hugely different from what is in our foods today. For instance, with cattle we were taught from an early age that cows eat grass, but the majority of the cattle reared in the UK today are intensively reared and fed on a predominantly grain based diet and vegetable oils. Grains and vegetable oils are very high in Omega 6, whereas grass has decent levels of Omega 3 in it (I am not saying we should be eating grass directly!). Therefore, the majority of the meat and dairy consumed today has far higher levels of Omega 6 in it, that would have ever been in the foods of our ancestors.

    Furthermore, as proof to the continuing preponderance of Omega 6 fats now in our diets, in 50 years the availability of soy oil (the second most consumed vegetable oil) has gone up by 320%. To give a comparison the availability of sugar and sweeteners has only gone up by 20% in the same 50 year period (1962-2009).

    I believe that there is a place for the OMS diet within the MS community, and also the wider population. I know you are an avid follower of Zoe Harcombe, and the documentary she featured in, Fat Fiction was very enlightening in regards to the dietary guidelines we have given all these years, and the motivations for them.

    However, in contrast to what Harcombe has advocated for – a diet consisting of grass fed meats and dairy products – is just not feasible for the majority of the population…not enough is being produced at present, and what is being produced, is expensive. Also, talking to a friend with MS, who is a single mum on benefits, she cannot nowhere near afford to be purchasing such products.

    This is why the OMS diet has a place. It is about reducing the amount of Omega 6 in the diet, by not frying with oils (n.b. frying with oils to the extent we do only became a thing last century anyhow), eating whole foods, eliminating processed foods from the diet, and supplementing with good quality Omega 3 (in the form of flaxseed oil) and eating fish 2 -3 times a week – oily fish preferably and which is often the less expensive of the types of fish available. This diet is so much cheaper than the Ketogenic diet being marketed by the Fat Fiction documentary.

    What I am interested in finding out about further is could Omega 3 really have an impact for MS? Dr Andrew Jenkinson mentions in his book ‘Why we eat too much’ that the brains of MS sufferers have low Omega 3 levels in them…is there any truth to this? I know he is looking into an Omega 3 deficiency as a reason for the ever increasing obesity rates we are seeing. And Professor Felice Jacka has been looking in to low Omega 3 levels as a factor for depression.

    The OMS program provides a structure for people with MS to really look at their diets, improve their Omega 3 to Omega 6 ratio, to cut out the processed food and eat more whole foods – the latter two points of which are what we are being encouraged to do by the government anyhow. It also addresses the amount of exercise people do, that mediation is beneficial (they are teaching mindfulness in schools now!), and to take vitamin d supplements which most neurologists seem to agree with. By following the program it makes you think that you can do something to help yourself with your illness, rather than taking a ‘fingers crossed’ approach. It makes you think you have a little bit of control back, rather than relying on healthcare professionals and research scientists to come up with a cure, and prevent you from being bed ridden before you reach retirement.

    • “We’ve known for a while that both genetics and the environment play a role in the development of MS,’’ said senior author David Hafler, William S. and Lois Stiles Edgerly Professor of Neurology and professor of immunobiology and chair of the Department of Neurology. “This paper suggests that one of environmental factors involved is diet.”

      People will say NSS. Salt and fatty acid….This one can be a Journal Club but not by me:-)

By Prof G



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