A diet high in saturated fat, trans fat, or cholesterol can directly raise cholesterol levels. But not all fat has the same effect on raising cholesterol. Fat found in tropical oils, such as coconut and palm kernel oil, has the greatest effect on raising cholesterol. Check the ingredients on the labels of your foods to find out whether a processed food contains tropical oils.

Trans fatty acids or partially hydrogenated vegetable oils are found in hard margarines, snack crackers, cookies, chips, and shortenings. Hydrogenation is a process that makes the fat solid or semisolid.

Monounsaturated and polyunsaturated fats, such as those found in olive, canola, safflower, and peanut oils, may improve cholesterol levels when they are substituted for saturated fat and trans fatty acids.

Although only about 20% of cholesterol comes directly from the diet (the other 80% is produced by the liver), a diet high in cholesterol and some saturated fats can cause the liver to produce more LDL ("bad") cholesterol.

Each person's body processes cholesterol differently. How much a person's diet influences his or her cholesterol levels varies from person to person and is probably determined by inherited characteristics. Some people who eat high-cholesterol diets have very high cholesterol levels. Other people who eat high-cholesterol diets may have normal or low levels.