Measuring the nutritional value of fats and oils, there are two main criteria: one is to look at the unsaturated fatty acids and unsaturated fatty acids molecules in the number of double tendons. The molecular structure of the fatty acids in the double tendon, known as unsaturated fatty acids; no double tendon known as saturated fatty acids; there are two or more double tendon, known as polyunsaturated fatty acids. Fatty acids in the molecular structure of the double tendon more, that is, the higher the degree of unsaturation, the higher the nutritional value. Vegetable oil contains more unsaturated fatty acids than animal oil, low melting point, at room temperature is liquid, easy to be digested and absorbed by the human body. Animal oil in addition to oil containing unsaturated fatty acids, other animal fats and oils are due to the high content of saturated fatty acids, so the melting point is high, digestion and absorption rate is low.