These fats are solid at room temperature. They include animal fats (not fish), and just a few vegetable fats: Coconut, Palm, and Palm Kernel Oil. These are natural oils that have been used around the world for thousands of years in their natural unrefined state and can have beneficial and healthful effects.
These fats are liquid at room temperature and liquid when refrigerated. They include most nut and seed oils, corn oil, cottonseed and soy oil. There is a class of polyunsaturated fats known as Omega III fatty acids. They are found in fish oils, flax oil, canola, and walnut oils. They are often deficient in a standard American diet. These fats are believed to be essential in protecting the integrity of cell membranes and in protecting and supporting immune system function. They are anti-inflammatory, necessary for growth and reproduction, and because of their ability to help prevent blood from clotting, they are thought to be protective against heart attacks.
These fats are liquid at room temperature and some (peanut and olive, for example) may harden when refrigerated. They are found in olive, canola, peanut, avocado, and high oleic sunflower and high oleic safflower oils. These fats are more stable in light and heat than polyunsaturated fats.
These fats are made from liquid fats that have hydrogen pumped into them in order to make them solid at room temperature. This allows for greater shelf stability and a “flaky-like” texture, which is popular among food manufacturers. These are poor quality fats and should be avoided whenever possible. Common sources include shortening, commercial peanut butter, most commercial baked goods, processed foods, and margarine.