In the past 50 years, saturated fatty acids (SFAs) have played a key role in hypotheses relating diet to the risk of coronary heart disease. More recently, the international debate questioning the role of reducing intakes of saturated fat in the prevention of cardiovascular diseases has been re-opened. According to the past negative assumption, SFAs are indeed still considered as a single group even if it is now well-known that they do not have similar levels in common foods, nor similar metabolic fates and cellular functions. In addition, recent findings on the metabolism and biological functions of individual SFAs show that they have important and specific roles in the cells. Elucidated biochemical mechanisms such as SFA protein acylation (N-myristoylation, S-palmitoylation and ghrelin octanoylation) and regulation of gene transcription are presented. In terms of physiology, SFAs are involved for instance in lipogenesis, fat deposition, polyunsaturated fatty acid bioavailability and apoptosis. The variety of their functions demonstrates that SFAs should no longer be considered as a single group. Consequences on the current nutritional dietary recommendations are finally discussed. The international debate questioning the role of reducing intakes of saturated fat in the prevention of cardiovascular diseases has recently been re-opened. Saturated fatty acids are indeed still considered as a single group even if it is now well-known that they do not have similar levels in common foods, nor similar metabolic fates and cellular functions. The variety of their functions demonstrates that saturated fatty acids should no longer be considered as a single group. Consequences on the current nutritional dietary recommendations are finally discussed.