Fats

FATS are essential parts of a healthy diet, are important in normal brain development, and are necessary for healthy skin, energy, heat and to assist in the absorption of fat soluble vitamins and calcium. They are the most concentrated form of energy available to the body. Unfortunately this means it is also the body's preferred method of storing energy. There are two main types of fat: saturated fats and unsaturated fats.

Saturated Fats

Saturated fat is solid at room temperature. It is the main dietary cause of high blood cholesterol. It is found mostly in foods from animals and some plants.
Animal sources include beef, beef fat, veal, lamb, pork, lard, poultry fat, butter, cream, milk, cheeses and other dairy products made from whole milk. These foods also contain dietary cholesterol.
Plant sources include coconut oil, palm oil and palm kernel oil (often called tropical oils), and cocoa butter.

Unsaturated Fats

Unsaturated fats are liquid at room temperature. They have very little effect on cholesterol, but some vegetable oils such as olive oil and sunflower oil actually lower cholesterol. Many fish oils are unsaturated fats which contain omega oils and can help prevent cardiovascular disease. Polyunsaturated Fats and Monounsaturated Fats are the two unsaturated fats. They are found primarily in oils from plants. Both polyunsaturated and monounsaturated fats may help lower blood cholesterol level when they are used in place of saturated fats. A moderate intake of all types of fat is best. Sources of polyunsaturated fats include fatty fish, nuts and vegetable oils such as safflower and sunflower. Sources of monounsaturated fats include olive oil and peanut oil.

Hydrogenated Fats

During food processing, oils may undergo a chemical process called hydrogenation where it is saturated with hydrogen by breaking the carbon double bonds and attaching hydrogen. This is done by heating the oil and adding pressurized hydrogen gas and a nickel catalyst. This produces "partially hydrogenated vegetable oil" which is common in margarine and shortening. These fats raise blood cholesterol.

Trans-fatty Acids

Unsaturated fatty acids can be in one of two shapes - "cis" and "trans." These terms refer to the physical positioning of hydrogen atoms around the carbon chain. The cis form is more common than the trans form. Trans-fatty acids (TFAs) are found in small amounts in various animal products such as beef, pork, lamb and the butterfat in butter and milk. TFAs are also formed during the process of hydrogenation.

To make foods that will stay fresh on the shelf or to get a solid fat product, such as margarine, food manufacturers hydrogenate polyunsaturated oils. When unsaturated fatty acids are hydrogenated, some of the hydrogen atoms are added on opposite sides of the molecule to the already attached hydrogen. Cis double bonds convert to trans double bonds, and the fatty acids become saturated.

TFAs or hydrogenated fats tend to raise total blood cholesterol levels. TFAs also tend to raise LDL (bad) cholesterol and lower HDL (good) cholesterol when used instead of natural oils. This may increase the risk of heart disease.