The evidence for saturated fat is unclear. Some state there is evidence of benefit from reducing saturated fat, specifically a benefit from eating polyunsaturated fat instead of saturated fat. While others state there is little evidence that reducing dietary saturated fat or increasing polyunsaturated fat intake affects heart attack risk. Dietary cholesterol does not appear to have a significant effect on blood cholesterol and thus recommendations about its consumption may not be needed. Trans fats do appear to increase risk.

Blood cholesterol has a significant impact on what?