What is the desirable ratio of saturated, polyunsaturated, and monounsaturated fatty acids in the diet?

By reducing intakes of animal fats and gradually reducing intakes of trans fatty acids, a one-third reduction in cholesterol-raising fatty acids seems practical, from 12% to 7-8% of total energy intake. The intake of polyunsaturated fatty acids should not exceed current intakes, approximate to 7% of total energy. Although further research is needed to determine a recommended ratio of oleic acid to carbohydrates, on the basis of the relatively low rates of coronary artery disease and cancer in both the Mediterranean region (where oleic acid intake is high at the expense of carbohydrates) and in populations consuming low-fat, high-carbohydrate diets, a reasonable compromise is a diet in which total fat is approximate to 30% of energy, allowing for an intake of oleic acid of 15-16% of total energy.