Although there has been recent controversy, the evidence that saturated fat increases risk of heart disease is clear although the extent to which this is true depends upon that which replaces this type of fat in the diet. This point is nicely illustrated by the results of a combined analysis of Nurses' Health Study (n= 84,628 women) and the Health Professionals Follow-up Study (n=42,908). During 24 to 30 years of follow-up, there were 7,667 cases of CHD. Replacing 5% of energy intake from saturated fat with equivalent energy intake from PUFA, monounsaturated fatty acids, or carbohydrates from whole grains was associated with a 25%, 15%, and 9% lower risk of CHD, respectively. However, replacing saturated fats with carbohydrates from refined starches/added sugars was not significantly associated with CHD risk.
Source: Li Y, Hruby A, Bernstein AM, et al. Saturated fats compared with unsaturated fats and sources of carbohydrates in relation to risk of coronary heart Disease: A prospective cohort study. J Am Coll Cardiol. 66,1538-48 (2015). http://www.ncbi.nlm.nih.gov/pubmed/26429077