About 30% of the calories in the basic healthy diet are fat, and only 10% of this is saturated fat. Many people eating a westernised diet eat too much of fat specially the saturated kind, and these high levels have been linked to several health problems. 

It is sensible to cut down your saturated fat intake if you are suffering from heart disease (including high blood pressure or angina). Cutting down total fat reduces the risk of cancer of breast, uterus, gall bladder and colon. 

Reducing fat intake is often hard. Concentrate on cutting down the amount of saturated fat you eat to about 10% of your total calories. Saturated fat predominates in animal fat (fat on and meat, poultry, eggs, milk, cheese, yoghurt, butter, lard and drippings) and many margarines and other cooking fats. It is unusual for anyone to eat too much unsaturated fat. This is found in many vegetable oils and soft margarines, fatty fish, nuts and seeds, as well as in smaller amounts in whole grain cereals and some vegetables and legumes. 

As you eat less saturated fat, the proportion of unsaturated fat in your diet automatically increases. This is good and may be medically helpful, for instance, in preventing or treating high blood pressure, heart disease, arthritis and gallstones.