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What Is Fat?

Fat is a nutrient that is essential for normal body function. It supplies energy and makes it possible for other nutrients to do their jobs. Unfortunately, we often consume far more fat than necessary, which can lead to excess cholesterol and obesity -- two factors that increase heart disease risk.

Saturated fat raises LDL cholesterol more than anything else we eat. It is usually solid at room and refrigerator temperatures and is found in animal products (fatty cuts of meat, poultry with the skin, whole-milk dairy products, and lard) and coconut and palm oils. Diets high in saturated fat are a major cause of high cholesterol and heart disease. Reducing the amount of saturated fat in your diet is a very effective way to lower LDL.

Unsaturated fats are usually liquid at room temperature and can be found in vegetable oils (canola oil, corn oil, olive oil, safflower oil, soybean oil, and sunflower oil), most nuts, olives, avocados, and fatty fish, such as salmon. Unsaturated fats do not raise LDL cholesterol levels, but they are high in calories, so they should be used in moderation.

Transfat increases LDL cholesterol levels. Foods made with hydrogenated vegetable oils, including many hard margarines and shortenings, are the main sources of transfats. Generally, the more firm these products are, the more transfats they contain.

Total fat. Food product labels will often list the total amount of fat they contain, including saturated, monounsaturated, polyunsaturated, and transfats. Although not all fat is a source of cholesterol, all fat is high in calories. No more than 35 percent of daily calories should come from fat.