Comment by themk
3 days ago
That seems to be searching for RCT's, which, I'm not surprised would struggle to replicate. Most of these had a duration of less than 5 years, while dietary related health outcomes are the result of decades of following a pattern. It's possibly also unethical, in some cases (i.e. the existence of effective LDL lowering medication would likely complicate things).
Many people seem to disregard epidemiology, especially when it comes to nutrition (I think because it tends to support unpopular positions). But epidemiology has performed some excellent feats in the name of public health: cholera, smoking, pfao.
It is unfortunate that the large time-lines on these things make more rigor difficult, but I wouldn't throw out the epidemiology.
Epidemiology should generally be disregarded when it comes to nutrition.
There are exceptions when there are rare natural experiments (e.g. I forget the country, but the European one where some issue caused all flour for the country to be only whole-wheat, which led to clear nutrient deficiencies due to the phytic acid there) but in general there are way too many confounds, and measurement is far too poor and unreliable (self-report that is not just quantitatively but qualitatively wrong, and you can't track enough people nearly long enough), there is virtually no control whatsoever (diets and available foods shift considerably over just decades), and much of the things being measured lack even face/content validity in the first place (e.g. "fat" is not a valid taxon, and even "saturated vs. unsaturated" is a matter of degree).
We are missing so much of the basics of what are required for a real science here I think it is far more reasonable to view almost all long-term nutritional claims as pseudoscience, unless the effect is clear and massive (e.g. consumption of large amounts of alcohol, or extremely unique / restrictive diets that have strong effects), or so extremely general that it catches a sort of primary factor (too much calories is generally harmful, regardless of the source of those calories).
But even setting that aside, you can't define or study "Mediterranean diet" rigorously even in RCTs, so I don't see how you can think you are going to get much of anything here from epidemiological work that is going to lead to anything practically actionable.
Notably, the epidemiological study people like to dump on the most, largely did use natural experiments (i.e. they chose regions, that, at the time, had very traditional diets, without the convenience of supermarkets to mess it all up). They also didn't rely solely on food surveys, but actually measured the meals.
But all that aside, I don't actually follow a Mediterranean diet, and agree that one has to be careful here, because it is not well defined (or, it might be in some circles, but that differs from what the general population might expect).
The only reason I mentioned it was in response to
> The Mediterranean diet is regarded as quite healthy by many health professionals but, it is also high in carbs and fat.
Where I was pointing out that the fats in the Mediterranean diet (by pretty much every measure of what it means to be a Mediterranean diet), are not saturated, and it is usually saturated fats that are considered "bad".
That is, all I was trying to do was clear up the (common!) confusion about fats (they are not all the same).
Fair, the term may have been well-defined and measured in the original study, or in some specific circles. I was definitely thinking of the meaningless general thing "Mediterranean diet" has metastasized into today.
I also think it is better, rhetorically, to not draw support for the badness of saturated fats / differences of different fats by referencing the Mediterranean diet, since this rather looks like drawing upon narrow / weak science to support something that is in fact much more broadly supported by a larger variety of more careful work.
But yes, it is very important that people recognize there are huge differences here!
There are so many differences in lifestyle between the regions that they studied and other places that it is absurd to attribute the outcomes confidently to the diet. Especially when stress is a well known CVD risk in itself.
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