So far as I've been able to tell, and that's coming from somewhat of an actual research background, is that ~80% of the food studies I see coming out are crap. Pure, unadulterated, shameless crap. They may tell a truth about something, but its crap too. Here's the problem, most are too small, short term, narrow or artificial to produce any tangible results and most are engineered to prove a stance instead of exploring the information.
Worse, is the politically motivated agencies who push this rubbish to doctors and other various professionals who take it in without even reading the study in a critical fashion. They simply parrot back the synopsis they've gotten, and in short order, they're getting it 2nd, 3rd or fourth hand depending on their info source. How many times do we see "Eating food XXX helps promote weight loss", and doctors flood to it and act like it is going to change everyone. Those who read the study will find that there was found a weak correlation to food XXX and a higher mean delta in weight over 1 month of 0.25 lbs from a study of 10 women over 50 from a remote village down the street from the research university. No other controls were made except eating food xxx.
That's why I prefer to do my own research, then start asking questions. I'll admit, I read some claims and start following the trail of 'proof', either its one big circle, or it eventually leads back to a paper or 50, but inherently tends to suffer from the rumor game. You know the one, you say Big D has a big butt to one person next to you and by the time it makes it around the room, it becomes bill gates secretly has sex with blueberry pies to cure his lycanthropy.