New study: does the LCHF-diet lead to stroke and cardiovascular disease?

Today the tabloids in Sweden announced that a new study has found that LCHF (Low Carb, High Fat diet, Atkins, paleo diet etc) can increase risk of stroke. There has been lots of debates about these diets recently, so this was on the news bills. I took the time to read the original scientific paper and found several problems with the news reports:

The connection LCHF-stroke

Even the heading of the original paper mentions high-protein/low carb-diet, but what the researchers actually did was to send a questionnaire to women in a part of Sweden in 1991-92 and then measure the ”outcome” in terms of cardiovascular diseases. They found which of the women that had any such diseases, and used statistical methods to measure if there was any relationship between the variables diet and subsequent disease.

As far as I know there were no talk about Atkins or LCHF at that time in Sweden, I would estimate that approximately 0 % of the women in the sample followed any diet similar to LCHF.

This makes the conclusions dubious at best. As far as my understanding goes the study cannot say very much about the consequences of LCHF or similar diets.

The link high protein-stroke

But, you might say, there was after all a strong statistic correlation between eating little carbohydrates and lots of protein and cardiovascular disease. The problem is that this correlation might be a sign of another confounding variable. To illustrate this in a simple way, let’s say that there is a big ”normal” cluster of women in the sample eating some sort of average food, and then a smaller ”vegetarian” cluster, eating less protein and more vegetables, and then a ”hedonistic” cluster eating more fat, meat, sauces with cream in etc. Then, with my knowledge of the situation in Sweden at that time, I would guess that the ”vegetarian” cluster was most ambitious with exercise and drank the least alcohol and smoke less. And then ”hedonistic” women probably behaved the opposite, smoked more, drank more and exercised less, on average. (I should stress here that they have used a statistical method to standardise the ratios of carbohydrates/fat/protein, so it makes sense to assume that these clusters will really be visible in the study)

The study mentions taking some account for this, looking at smoking and alcohol use. But it does this with variables that are very coarse, dividing the sample into only three groups concerning alcohol intake. And they don’t take exercising into account at all.

This makes it quite possible that what they are really measuring is a correlation between protein/carbohydrate intake and general lifestyle variables like smoking and exercise.

What does this has to do with the themes of this blog?

This subject is not really related to the themes of this blog: psychology, parenting and psychotherapy. But I think it shows how scientific reports in both reputed journals and in mainstream media can be flawed and biased.

Another more important reason that these things might be of interest to the readers of this blog is that as I wrote when reviewing the Paleo-diet-site Marks Daily Apple (MDA), there are new and very interesting research coming about a connection between inflammatory processes in the body and at the same time there are signs that paleo-diet (a diet with similarities to LCHF) can decrease those inflammatory processes. And on MDA there are actually quite interesting reports about depressed people recovering using that diet. There are also other reports saying that a ketogenic diet (with little carbohydrates) can be helpful for depression. I absolutely don’t want to claim that there is any sort of scientific clarity on this, I just want to say that we should keep our eyes open and curious towards this area, and look at different hypotheses with an open mind.

Note 1: For clarity I would like to stress that I do not mix dieting advice into my practice as a psychologist, rather I very much urge people with eating issues to first look at the psychological aspect of their eating.

Note 2: The study is: Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study by Lagiou, Sandin, Lof (Löf), Trichopoulos, Adami, Weiderpass in British Medical Journal.

Review of Mark’s Daily Apple

For the September issue of the magazine YourLife, I was interviewed by a journalist about my views of the recent trend with exercise forms that are both hard and integrate the whole body, like cross-fit and military training. It was quite flattering for me, who was always very ordinary in sports, to get to talk about exercise alongside the fitness icon Dolph Lundgren…

I gave a rather dull psychologist-answer: that these forms of exercise look really impressing, but for the majority of people the big challenge is to start exercising at all. Since then I have been following occasionally the blog Mark’s Daily Apple, and in spite of my misgivings, I do find it quite fascinating. I have even tried a couple of the concepts of the blog, like barefoot running, and I like it a lot.

Mark’s Daily Apple is the blog of former triathlet Mark sisson about ”grok-living” or ”following the primal blueprint”. The idea is that since the human race have spent most of its days as hunterers-gatherers, our genes are programmed to certain forms of diet and exercising, and if we obey the rules of our genes, we’ll be much more healthy and happy. The diet is very similar to what we in Sweden call LCHF – but with a lot of vegetables and somewhat more carbohydrates. The exercise is a combination of barefoot running, heavy lifting, sprints etc.


These are the strong points that I find in the concepts of Sisson:

* For a person who wants to stay healthy in our modern society, there are many temptations. Where I live they have recently placed an automatic vending machine for candy, so we can basically get it any time of the day, like if you return tired from work at 10 pm. Here it can be a great help to work together with other people to keep on a healthy track, like I see people doing at MDA. See for example this video.

* The exercise ideas seem quite sane to me, Sisson carefully stresses that it is important not to exercise too much. Training two to four times per week is encouraged.

* As ways of losing weight, LCHF and paleo might have some advantages. Swedish speaking readers can find good reviews of the research on this on träningslä

* Sisson also have some very interesting posts on IBS and depression – in short there are some very preliminary evidence that this diet might be helpful with these and some other nasty conditions. I would be very interested in seeing more research about this.

* There is something in the general ambiance of this site that I like a lot. Some sort of warm enthusiasm that is caring about Mother Nature.

The flip-side of the coin

I also see weaker spots:

The concept of primal living

The big components of the primal lifestyle seem to be diet and exercise. The more you read the blog, the more this lifestyle seems attractive and self-evident. But in fact there is no real logic that one need to package together paleo-diet with particular forms of exercise. The ”primal” people do not seem so interested in paleolitic dancing or caveman worship, for instance. Living ”Grok” is a nice and cosy idea that may appear really authentic, but in fact, it is very much a concept that is adapted to the modern 21-century rich world (Grok is the imagined forefather that you want to imitate in this lifestyle).

Some people seem to feel that Primal/Grok lifestyle resonates perfectly with how they want to live their lives, and for them of course this is a way to a more healthy and fulfilled life. But for the many of us who are struggling with keeping an exercise regime at all, it might be too difficult a task to try and model both our exercising and our diet according to these concepts. The threshold might be too big.

My suspicion that this is not so much a concept for ordinary couch-potatoes, is supported by the fact that most of the people featured on the blog seem to have been fitness nerds already before they started with the ”primal” lifestyle.

I see a larger problem of public health here. Around 50 % of the population in the western world are chronic couch potatoes, and don’t even take walks regularly. This is a huge public health problem. They are at risk for all sorts of serious diseases like cancer, heart disease, diabetes and other. I think many of these people have negative views of themselves and negative views of exercising that makes it more difficult for them to stick with some exercise habits. They might think that exercising is not for them, or that exercising are for ”nuts” (hurtbuns, we say in Swedish…). These views might be reinforced by looking that sites like MDA.

If you look at magazines, newspapers or on the internet, there are tons of information geared towards people who are already into exercising, but very scarce material for all those people who need help to get started with some simple exercising and to learn to stick with it.

So this critique does not concern only MDA, but I really think it might be helpful it if was more sincere about targeting people who already have healthy lifestyles.

What life does this really lead to?

While I find the general ambiance on the blog quite nice and relaxed, in the forums I see signs that many people maybe take this lifestyle a little bit too seriously. In this thread for instance people seriously debate if one ought have some sugar after exercising. Of course, there might be some way of scientifically answer this issue, but I can’t help but thinking: aren’t there more exciting things to do in life than debating this? The other day I saw a Zumba clip on YouTube. They use the word ”party” in every sentence, and when compared to some things on MDA, Zumba seems a much more vibrant and fun way of spending your leisure time if you want to become fit.

Too much focus on ”looking gourgeous”

I get quite a mixed picture here. Often I get the impression that this is a concept where you want to turn your back to many of the things of contemporary life, like TV, cars and big cities, and live closer to nature and the basics of existence. But at the same time, there is a lot of focus on how the primal lifestyle makes you look good in a conventional 21-century way.

As far as my understanding goes, the paleolitic man didn’t have the resources to worry about how (s)he was looking – they didn’t even have mirrors. And if they wanted to change their bodies in some way, I believe their primary dream would be to be more fat.

An example is the recently published story about a woman who is around 50 and she starts out with a body quite normal for her age, not at all overweight or obese. She then does an ambitious ”primal” plan and in the end there are photos where she smiles and has a body of a traditional ”skinny model”. And then there are dozens of comments where people praise her work with words like ”you look gourgeous”. This is the type ot text that I would absolutely not want any insecure teenage girl to read. It really supplies a recipy for eating disorders complete with diet and exercise tips, and literally promises that losing a lot of weight will give you appreciation and love.


So in the end my review is quite mixed. The concept of following the primal blueprint might have a lot offer to some people but I would strongly encourage Sisson and his friends to take a closer look on their attitude to ”looking great”.

Notes: Mark Sissons book on Adlibris, Bokus.
Swedish text
on ”primal” exercise.