Fats and oils are the most concentrated forms of energy in the diet. They are derived from a variety of sources, including seeds, nuts, vegetables, and animal products. Fats and oils are divided into four main categories. These categories refer to molecular structure, which determines how the fats act in the body. They are listed below, from most desirable to least desirable, from a healthy eating standpoint.
Monounsaturated fats stay liquid at room temperature but congeal when refrigerated.
Oils high in monounsaturated fats include olive, canola, peanut, avocado and almond oil. Polyunsaturated fats stay liquid both at room temperature and in the refrigerator. Oils high in polyunsaturated fats include corn, safflower, sunflower, soybean, sesame, and walnut oil. Saturated fats stay solid at room temperature. Foods high in saturated fats include butter and lard, as well as coconut and palm oils.