Virtually all studies on this topic have been association studies, that is, not causation proof. It is really hard to look at a single macronutrient over time and blame it or celebrate it.
Some of the earlier ‘saturated fat is bad for you studies’ even grouped cake and biscuits in with saturated fat intake. Completely different nutrients and makes a mockery of those guidelines that developed accordingly.
Recent studies have not shown a major reduction in cardiovascular risk with reducing saturated fat intake.
The Sydney Heart Study raised concerns that replacing it with polyunsaturated fats might be the cause of an increased rate of disease.
I am still waiting for someone/anyone to explain how a saturated fat can chemically create an inflammatory condition at a blood vessel level. I have been throwing out that challenge for over 2 years! Nothing from anyone.
I can describe a pathway for a polyunsaturated oil to do the damage and that is the basis of the ‘Nutritional Model of Modern Disease’. The combination of Fructose, refined carbohydrates and Polyunsaturated oils makes a very simple model.
2015 Cochrane review update http://onlinelibrary.wiley.com/…/10.…/14651858.CD011737/full
2013 Sydney Heart Study http://www.ncbi.nlm.nih.gov/pubmed/23386268