The impact of replacing saturated fat with other nutrients
Reference 2 is written by the same authors as reference 1, and has the added notation "opinion". This is not a detailed meta-study, but rather a summary of many of the studies involved in trying to sort out the impact of replacing saturated fats with other nutrients. Here is a summary of their opinions:
Replacing saturated fat with polyunsaturated fat generally (but not in all studies) shows a reduction in cardiovascular disease.
Replacing saturated fat with monounsaturated fat also) shows a reduction in cardiovascular disease, but possibly to a lesser extent.
Replacement of saturated fat with a higher carbohydrate intake (particularly refined carbohydrates) can lead to symptoms of "metabolic syndrome" in which insulin resistance and obesity increase, possibly leading to increased risk of CVD.
The importance of this article is that it clearly specifies that the impact of a reduction in saturated fat consumtion depends on what one replaces it with. Obviously, one should not replace it with carbohydrates. A detailed study (WHI - the women's health initiative study, (reference 3) demonstrates this second point unequivocally . This is despite the fact that subsequent anaylsis of these data (reference 4) shows that the LDL ("bad") cholesterol was lowered by 8 to 10 mg/dL, leading one to expect some reduction in CVD (if one believes that LDL reduction reduces CVD - more on this topic elsewhere).
In addition, these results break with conventional wisdom in that monounsaturated fats (such as olive oil) were considered more healthy than polyunsaturated fats (e.g., fats from soy, corn and sunflower-seed oils, nuts and seeds). They also claim that there may be an optimum ratio between saturated and polyunsaturated fats, that promotes good heart health.