For decades a reduction of the intake of saturated fat has been the cornerstone in dietary prevention of cardiovascular disease. The main argument for this advice is its alleged influence on blood cholesterol. However, several recent trials have found no such effect in spite of intakes up to five times higher than the recommended upper limit. Even if true, the effect on blood cholesterol is indirect evidence. The crucial question is if a high intake is harmful or if a reduction leads to health benefits. Almost all epidemiological and experimental studies are in conflict with this assumption; indeed several observations points to the opposite. There seems to be an urgent need for a revision of the present dietary guidelines. . . .
The idea that too much saturated fat in the diet is harmful to human health has no support from ecological, dynamic population or case–control studies of the association between dietary saturated fat, or tissue saturated fatty acids, and cardiovascular disease, nor from meta-analyses of randomised, controlled, unifactorial dietary trials. Even if the author of this review has studied the scientific literature on this issue meticulously for 18 years, supportive studies may have been overlooked. However, a scientific hypothesis must be in accord with all observations; a few supportive studies cannot outweigh more than hundreds of studies that have falsified the hypothesis.