Recently a controversy arose in the scientific world because of a meta analysis:

Big fat controversy: Dietary fat and heart disease study is "seriously misleading"

In March 2014, the Annals of Internal Medicine published a meta-analysis that received a huge amount of media attention because it concluded there was no evidence of a link between dietary saturated fat and heart disease, contradicting decades of research and dietary advice. (The article is behind a paywall, but the abstract is available at http://annals.org/article.aspx?articleid=1846638.)

The criticism from other scientists began immediately but somehow got a lot less media attention than the original paper did. Nutrition researchers from Harvard wrote that the meta-analysis "contains multiple errors and omissions, and the conclusions are seriously misleading." (http://bit.ly/1oATOK5) The authors of the meta-analysis acknowledged several errors and posted a corrected version of the paper, but stood by their conclusions. (http://bit.ly/1jxyIJv)

This episode raises a lot of questions about media coverage of scientific controversies. The original meta-analysis received prominent coverage in The New York Times and was a cover story in New Scientist and several news papers and magazines around the world. Coverage of the corrections and the criticism, however, has been muted to nonexistent, potentially leaving a very misleading impression in many readers' minds that this one study overturns everything we've been told about dietary saturated fat for 20 years or more.

And science writers became confused.

'What responsibility do science writers have to report controversies like this? We know that rarely if ever does one new study overturn an entire body of previous research. It's no wonder the public is confused and more often than not simply ignores research-based dietary advice. What can science writers do about this?'

Are the questions they are asking.
I have reported about this too here long back when the controversy arose and added that one should take this meta-analysis with a pinch of salt!

Some people said this is true and some said this is not. And my reply to all these controversies:

Well, you cannot treat this problem in isolation. There are other factors linked to it too.
Like genetic predisposition to health problems ( if you are genetically predisposed to heart problems and have metabolic irregularities regarding cholesterol, dietary fats will have higher effect on you ) , your work and food habits ( excessive added salt which is the primary (not sole) cause of elevated blood pressure, weight gain and insulin resistance, increased inflammation, inactivity, tobacco smoking, are all modifiable risk factors that contribute to one's risk of developing atherosclerosis and having a heart attack and or developing heart failure. And there are certainly many other known and suspected CVD risk factors), your stress levels, the atmosphere you live in, the area you live in.

One of my relatives, who used to have lots of ghee ( clarified butter) never had any heart problem till his death in his nineties.  And we hear stories of  young men in their thirties and forties dying of heart conditions even though they took moderate saturated fats during their life times. This is confusing to laymen.
You just cannot say fats will or won't cause heart disease without taking several of these parameters into consideration because each of these factors influence the heart disease too.  Moreover, as people get older many more factors determine their overall health making the impact of high cholesterol levels less easy to detect. You have to have the whole picture to get to any reasonable conclusions.
What is true with people in some parts of the world need not be true with people from other parts of the world ( people are more prone to diabetes in this part of the world than other areas and studies conducted here might differ from the ones conducted elsewhere ).
How can you have such a narrow view that just fats cause/don't cause heart disease? Science writers should develop a broader view to put things in their right forms. They should analyse the problem in relation to other factors and report with clarity and should not confuse people with irresponsible reports.

And science writers and journalists, like I said before in one of my articles here, report the first analysis or report that is controversial and therefore, grab more eye balls, and refuse to get corrected by the experts. Years of work by the experts go waste with this type of sensational reports.