I would also caution against looking at journalistic reports of studies (and that includes the aforementioned Gary Taubes, as much as I admire him and loved his book, it is still 2nd hand info) and even study abstracts. You have to look at the data, and ideally have a clear idea of how appropriate the statistical tools used are to the data at hand. It is surprising but even in peer-reviewed journals, often studies are published with data that conflicts with conclusions. More often than not these are conclusions that support the theories du jour, so your more TF-leaning studies are likely to NEED impeccable data, statistical methodology and conclusions that are supported by the data. Taubes details one example of how the data didn't fit the conclusions in the massive Framingham study, but there are others. There is also sample size to look at, population, reality checks on the methodology...
...and you have to consider that the vast, vast majority of ALL nutritional studies are *epidemiological* in nature, which means that the study authors typically select for one variable and try to isolate a single correlational factor. Nutritional science is also HIGHLY reductionist and attempts more often than not to draw "nutrient X = condition Y" relationships, where the reality of the situation might be more like "nutrient X in combination with genetic base Q, environmental factors M, N, L and B, combined with nutrients T and V for females of reproductive age = a 50% greater risk of condition Y". Because that sort of thing just doesn't sell.
I used to be a total study junkie. Then I took classes on statistical methodology and research methods, and realized that the massive ethical constraints on ANY research involving humans means that you can virtually NEVER get anything stronger than a correlational result from any human studies, and that it's incredibly difficult to design a study that will produce accurate data that is also well-suited to any statistical analysis (ie, how important are the outliers? Do you look at the mean results or median? Is the data truly on a bell curve or are you just trying to cram it into one and use the conveniently handy tools?).
Also, many many studies are performed and the results never published, since studies are frequently funded by organizations with a vested interest in results that say certain things. Not to mention the vast numbers of studies with completely inconclusive findings.
So, my thinking is that studies are interesting and fun to read and analyze, they keep bright people employed and happy, but they don't do a whole hell of a lot to help us *really* understand what to eat. Human bodies are SO complex and nutrition is even more complex; there is this whole mess of environmental variables, human genetics and epigenetics that nobody pretends to understand, and the fact that science is reductionist by necessity... it all adds up to the unfortunate conclusion that it's probably not a good idea to put any faith in scientific studies as a basis for diet planning.
So what's left? Merely the simple but inarguable thought that foods that have been consumed for thousands of years without killing anyone are likely to be reasonably healthy for you too. This seems simple but there is the problem of history and its accuracy - the problem that when foods don't change over millenia nobody thinks to record their details, the problem of the vast variety of traditional food and the lack of knowledge about whether there are any smorgasbord effects from combining even traditional foods, the ongoing problems of soil health, the interaction of diet and lifestyle... PLUS you have to take into account your own unique set of variables, including your childhood, your culture, your own biology and psychology.
Just a brief example to illustrate some of the problems: Say there is a study that shows that eating small oily fish (like sardines) is highly beneficial to health. The sample population is drawn from three or four countries with high per-capita consumption of sardines; these countries have lower incidences of cardiovascular disease than several other non-sardine eating countries.
Ok, great, you say - gimme some sardines. But wait. Are the sardines tinned or fresh? How are they prepared? Are they salted at all? Breaded? Fried, grilled or marinated? Served with sour cream, or lemon juice? What about the other 145 or so countries in the world? Do they eat sardines? What are THEIR cardiovascular disease stats? Why did the study authors choose THESE countries, and not others? What else do the people in these countries eat along with their sardines? What about the fact that sardine fisheries are seasonal? Does that matter? Who funded the study? Was it a fishery lobby group? An environmental group trying to shut down salmon farming or wild salmon fisheries? Who reviewed the study? Did the reviewers ask any of these questions? Does the data actually fit the conclusions? Can you tell?
Sorry, this is a bit of a rambling post. My point is, I think logic, self-knowledge and common sense are better tools for deciding what to eat than scientific studies.
but PM me if you want the link!
