Good Fats Vs Bad Fats

There are many different kinds of fats, but each kind is a variation on the same chemical structure. All fats consist of fatty acids (chains of carbon and hydrogen atoms, with an oxygen atom at one end and occasionally other molecules) bonded together.

In human diet fats and cholesterol-carrying lipoproteins play central roles in the overall development of the body. The two main types of lipoproteins basically work in opposite directions.

Low-density lipoproteins (LDL) carry cholesterol from the liver to the rest of the body. When there is too much LDL cholesterol in the blood, it can be deposited on the walls of the coronary arteries. Because of this, LDL cholesterol is often referred to as the "bad" cholesterol.

High-density lipoproteins (HDL) carry cholesterol from the blood back to the liver, which processes the cholesterol for elimination from the body. HDL makes it less likely that excess cholesterol in the blood will be deposited in the coronary arteries, which is why HDL cholesterol is often referred to as the "good" cholesterol.

In general, the higher our LDL and the lower our HDL, the greater the risk for heart disease.

Knowing which fats raise LDL cholesterol and which ones don't is the first step in lowering the risk of heart disease and maintaining a healthy body. Saturated fat, trans-fatty acids and dietary cholesterol raise blood cholesterol, whereas, Monounsaturated fats and polyunsaturated fats don't. 

 
Saturated fat is the main dietary cause of high blood cholesterol. It is recommended that our diet should derive only 25–35 percent of calories from fat, with less than 7 percent coming from saturated fat. Cholesterol is limited to less than 200 milligrams a day.

Saturated fat is found mostly in foods from animals such as beef, beef fat, lamb, pork, lard, poultry fat, butter, cream, cheeses and other dairy products made from whole milk and some plants which include coconut oil, palm oil and palm kernel oil (often called tropical oils), and cocoa butter.

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 (TFA) are found in small amounts in various animal products such as beef, pork, lamb and the butterfat in butter and milk. TFA are also formed during the process of hydrogenation and making margarine.

Polyunsaturated and monounsaturated fats are the two unsaturated fats. They're found primarily in oils from plants.

Polyunsaturated include safflower, sesame and sunflower seeds, corn and soybeans, many nuts and seeds, and their oils, while monounsaturated fats include canola, olive and peanut oils, and avocados.

Both polyunsaturated and monounsaturated fats may help lower blood cholesterol level when used in place of saturated fats in diet. It is usually advisable to eat moderately from the fat group and more of the unsaturated types.