It doesn't really matter if it's peer-reviewed or how many variables they controlled for. It's still an observational study and not a randomized controlled trial.
Observational studies are not completely devoid of value. They are in many cases the only way we can practically learn about certain aspects of our world.
Randomized controlled trials are better, of course.
Nutrition epidemiology studies are not scientific experiments; they are wildly inaccurate, questionnaire-based guesses (hypotheses) about the possible connections between foods and diseases. This approach has been widely criticized as scientifically invalid [see here(1) and here(2)], yet continues to be used by influential researchers at prestigious institutions.
Even if you think epidemiological methods are sound, at best they can only generate hypotheses that then need to be tested in clinical trials. Instead, these hypotheses are often prematurely trumpeted to the public as implicit fact in the form of media headlines, dietary guidelines, and well-placed commission reports like this one.
Tragically, more than 80%(3) of these guesses are later proved wrong in clinical trials. With a failure rate this high, nutrition epidemiologists would be better off flipping a coin to decide which foods cause human disease.
Although, potentially interesting: Self reported mental well being is correlated with self reported belief of eating more fruits and vegetables. Though a much weaker claim than the headline, I think this is still useful information. Without looking at the study, you can't rule out that there was something about the surveys that caused this correlation, but if there wasn't, it certainly would be interesting to try to find out why this correlation exists.
John Ioannidis, the guy behind "Why Most Published Research Findings Are False" has recently gone after nutrition research. Turns out that nutritional studies are basically devoid of value. After decades of nutrition research we know almost nothing about how to eat healthy.
Anyone else here not even bother reading about new psychology findings? Ever since learning about the "replication crisis" and seeing how so much popular psychology has fallen victim to it (e.g. priming, ego depletion, power poses, impicit bias, stereotype threat)
I wonder if news organizations will bring in rules not to report on them until there's been a number of successful replications. They just mislead people.
Banning all those accounts based on a tiny minority of tweets promoting fake election dates seems like totally bs reasoning. If their reasoning for the bans was actually a policy against "dehumanizing speech" as some have said, then why not ban everyone who tries to dehumanize a Trump supporter with an accusation of them being a "Russian bot?" Or what about dehumanizing language against opponents like racist/sexist/Nazi/homophobic/transophobic etc?
Also.. I think this meme has a grain of truth to it - I don't know about the political aspect, but as to people's minds generating the same content and repeating the same phrases over and over: it seems as if our popular media is pretty limited in the things journalists and TV hosts are "allowed" to cover and say. Late night hosts all seem the same. That's one reason I enjoy 4chan, because the content is so diverse.
