The "butter is good" study has some serious flaws

You may have heard that science proves saturated fat is good for you — or, at least, that it's not the devil. That claim is based on a meta-analysis, a study of studies that reviews a wide variety of research on a given subject. Meta-analyses are a great way to get a big-picture view of what science says about a subject and the results of one of these papers means a lot more than the results of a single study, on its own.
Trouble is, this particular meta-analysis has a lot of flaws, writes James McWilliams at the Pacific Standard. Chief among them: The authors left out a couple of key studies that came the opposite conclusion and they misrepresented the results of a third. That doesn't mean butter IS the devil. But it does mean that you should pause before declaring this particular paper the final word on what is and isn't healthy to eat.