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The concept that saturated fat causes heart disease first gained traction back in the 1970s on the publication of a seminal study that purported to show a clear association between the amount of saturated fat consumed in seven countries, and the risk of heart disease in those countries.28 The findings of this study are summarized in the figure below.

This study has been cited extensively since its publication as convincing evidence that eating saturated fat causes heart disease, and is widely recognized as a major driver of the fear of saturated fat that persists to this day. Yet, while it represented quite a turning point in our beliefs about saturated fat, one of this study’s major weaknesses is that it is epidemiological in nature, which means it can only tell us about the relationship between saturated fat and heart disease, and not that saturated fat causes heart disease.

Differences in heart disease may, possibly, have been due to differences in so-called ‘confounding’ factors (such as smoking or levels of activity) that tend to differ a lot between countries. Also, the study drew on very limited data (from just seven countries). What happens when we take a wider view?

Data from other countries available at the time has been added into the graph below.

As you can see, the clear relationship that existed before has now disappeared. The original use of data was selective (and misleading), and we can be similarly selective, too, if we wish. How about if we choose the points on the following page instead?

Now, apparently, we see that the countries with the most saturated fat in their diets have the lowest rates of heart disease.

This may seem far-fetched, but let’s suspend judgement for a moment until we discover what the most up-to-date data turns up. In the following graph, I have put forty-five countries from the European region in order of ascending levels of saturated fat in the diet (represented as black dots).29 I’ve put in a trend line too (going upwards from left to right).

Within the graph, I have also added death rates due to heart disease for the same forty-five countries (represented by white dots). The points are scattered on the left-hand side, but notice how they cluster down to the right-hand side. I’ve drawn a trend line for these points too.

Taking as wide a view as possible, this graph shows that as saturated fat intake rises, deaths from heart disease fall.

Much as this evidence supports the evolutionary theory of nutrition beautifully, it is still epidemiological in nature, and can therefore only tell us about the relationship between saturated fat and heart disease (and not whether or not saturated fat causes heart disease).

That said, the facts are:

 It was epidemiological evidence that was originally used to incriminate saturated fat back in the 1970s

 The original data was very selective in nature

 More recent and complete data show the polar opposite finding: that higher intakes of saturated fat are associated with lower risk of heart disease

For what it’s worth, all recent reviews of the epidemiological evidence have simply failed to find an association between saturated fat intake and risk of heart disease.1,30,31 All this weight of epidemiological research, however, will never trump the results of intervention studies, where the health outcomes of individuals eating lower-fat diets are compared with those who eat fat to their heart’s content. What does the evidence show here?

The most comprehensive meta-analysis in this area amassed the results of forty-eight individual studies.32 Each of these studies tested the effect of either reducing the amount of fat in the diet (especially saturated fat) and/or modifying fat in the diet (such as replacing saturated fat with supposedly healthy ‘vegetable oils’ (see below for more on these). The review assessed the impact of these dietary changes on the risk of chronic conditions and the overall risk of death. (Note: risk of death is ultimately 100 per cent for all of us, of course, but in these studies risk of death is assessed over a finite period of time. This allows researchers to compare the numbers of deaths in different groups over this set time period.)

This biggest and best review of the evidence revealed that when individuals eat less saturated fat and/or replace it with ‘healthier’ fats, there is:

 No reduction in risk of heart attack

 No reduction in risk of stroke

 No reduction in risk of diabetes

 No reduction in risk of cancer

 No reduction in risk of death from cardiovascular disease (e.g. death from heart attack or stroke)

 No reduction in overall risk of death

In other words, no benefits are found at all. If eating less saturated fat or replacing it with supposedly healthier fats does not improve health or extend life, one might ask what’s the point of eating this way? The point is: there is no point.

Bearing in mind just how often and vociferously we’ve been told that saturated fat gums up our arteries, this notion may come as a shock. Yet it is utterly in keeping with the primal principle: saturated fat is a component in red meat and has been part of the human diet for as long as we have been, well, human.