I agree with Two Tribes regarding the lack of true knowledge re other factors that lead to the conclusions drawn. It’s the same for any trials such as statins being good for you or not, the evils of sugar, fat and so on.
There are also two massive factors to take into account with all these sort of analysis. The first is “confirmation bias” - that is, what was the scientist looking to show to start with and the extent to which the data has been interpreted to prove his point, cleverly glossing over the associated factors that might also influence his result. (Such as those mentioned by two tribes). Or the less scrupulous researcher simply being clever with the numbers to prove his point - lies, damned lies, and statistics if you like.
The second, more hidden one, is who is behind the funding of the research. This is not always obvious as it might not be direct, but if (for example) the University has the promise of a new wing being built by Coca Cola any research done which shows links between the chemicals used in their diet drinks and health issues in humans is likely to be “modified” by the powers that be before publication.
Hence I take all studies with a massive pinch of salt (which may or not be good for you ) and avoid wherever possible processed foods and or chemical laden foods.
