These are commonly referred to as the healthy fats. These fats have been shown to have a benefit against heart disease and may assist in lowering cholesterol. Monounsaturated fats are also thought to ward off different types of cancers such as breast cancer and colon cancer. They are typically high in Vitamin E. A really good source would be olive oil, Canola (rapeseed) oil, avocados, almonds, and also peanuts. The best source, I believe, is cold pressed olive oil. It is best kept in a cool and dark place to ensure it doesn’t go rancid. You’ll notice that although a lot of margarines coming out state that they are not hydrogenated, although they maintain a certain solid consitency at room temperature. I think this is a good reason to avoid them because there certainly is a certain amount of chemical manipulation going on in order to ensure they remain solid.

You should also consider Omega -3 fatty acids!

Omega-3 fatty acids are a form of polyunsaturated fats, one of four basic types of fat that the body derives from food. (Cholesterol, saturated fat, and monounsaturated fat are the others.) All polyunsaturated fats, including the omega-3s, are increasingly recognized as important to human health. According to the American Heart Association, research has shown that these fats can reduce the risk of Cardiovascular disease by decreased risk of arrhythmias, which can lead to sudden cardiac death; decrease triglyceride levels; decrease growth rate of atherosclerotic plaque; lower blood pressure (slightly)

Scientists made one of the first associations between omega-3s and human health while studying the Inuit (Eskimo) people of Greenland in the 1970s. As a group, the Inuit suffered far less from certain diseases (coronary heart disease, rheumatoid arthritis, diabetes mellitus, psoriasis) than their European counterparts. Yet their diet was very high in fat from eating whale, seal, and salmon. Eventually researchers realized that these foods were all rich in omega-3 fatty acids, which provided real disease-countering benefits. Omega-3 fatty acids are also natural blood thinners, reducing the "stickiness" of blood cells (called platelet aggregation), which can lead to such complications as blood clots and stroke.

So with all that said, I'm sure you can appreciate that you can consume certain type of fat and fatty acids without feeling guilty. Now you know what type of fat to look for.