Saturated fatty acids are fatty acids that do not contain double bonds. In food, the carbon chain length of saturated fatty acids is mainly 8-1 8 carbon atoms, which are medium-carbon chain fatty acids (8:0 and 10:0), lauric acid (12:0), myristic acid (14:0), palmitic acid (16:0) and stearic acid (18:0). Among the fats contained in animal foods, saturated fatty acids account for 40%-60%, mainly palmitic and stearic acids, which constitute about 60% and 25% of saturated fatty acids, respectively. Like other fatty acids, saturated fatty acids have an important physiological function of providing energy in addition to constituting human tissues. Dietary saturated fatty acid intake significantly affects blood lipid levels. Evidence shows that elevated blood lipid levels, especially elevated serum cholesterol levels, are an important factor in atherosclerosis, and that dietary saturated fatty acids are the main fatty acids that increase serum cholesterol, so the World Health Organization recommends that dietary energy provided by saturated fatty acids should be less than 10% of total dietary energy. The effect of different types of saturated fatty acids on blood lipids varies: palmitic acid has the most pronounced effect on increasing serum LDL-cholesterol and total cholesterol levels, followed by lauric acid and myristic acid, and three fatty acids, lauric acid, myristic acid and palmitic acid, have been included in the list of those that raise cholesterol levels. Stearic acid does not have a significant effect on raising serum cholesterol or LDL-I cholesterol, which may be related to the rapid conversion of stearic acid to oleic acid in the body.