Animal fats, often contrasted with vegetable fats, are in fact a range of substances which differ greatly from each other in terms of their composition. In addition, the popular image that animal fats = saturated fats is entirely false, the same applying to the notion that the consumption of saturated fats, without differenciation, is harmful. Saturated fatty acids differ greatly from each other in terms of their metabolism and while some of them, in special circumstances, might be harmful, others are truly valuable. The aim of this document is to study this role and this value of fatty acids of animal fats and to identify their place in the human diet, though more particular attention will be paid to saturated fatty acids.