We are strongly advised to cut down on the amount of fat, especially saturated fat in our diet. In recent years the role of fats in the diet has excited much controversy and debate - there are some fats that by eating too much, they can be harmful to our health, while others are vital for the body and can actually help to prevent disease.

The fats in our food are definitely the most concentrated source of kilojoules - weight for weight they contain more than twice as much energy as carbohydrate or protein. A high fat diet is therefore likely to lead to obesity, and high intakes of certain types of fat can contribute to ailments such as heart disease and certain types of cancer.

Fats make food tasty and palatable. Dietary fats from oily fish, vegetable oils and dairy products, between them supply the essential fat-soluble vitamins A,D, E and K, as well as the essential fatty acids needed for a healthy skin and for regulating certain body functions. However, too much of any fats and oils may prove harmful. It's suggested that fats should provide no more than 30% of our total energy intake.

Fats and oils contain many different fatty acids which affect the body in varying ways. Most simply, they are classified as saturated and unsaturated. It is the saturated fat found in many animal products and the trans fatty acids found in some hardened margarines that should be restricted in our diet, as they have been known to increase the risk of coronary heart disease. However, not all margarines contain these trans fatty acids so check the nutrition panel on the product packaging for the types of fats found in the product.

Butter, cream, hard cheese, palm kernel oil, coconut oil and fatty meat contain a high percentage of saturates.

The principal sources are olive oil, canola oil and foods such as avocados, nuts and seeds.

Foods high in polyunsaturates include most vegetable oils and oily fish. These fats can also be broken down into 2 groups of essential fatty acids:

Good sources are olive oil and sunflower oil.

Good sources are soya bean oil, canola oil, walnuts, oily fish such as sardines, mackerel, salmon and enriched eggs.

Hydrogenated oils such as margarine and fats which are industrially hardened to avoid rancidity and processed foods such as biscuits, pies and chips are the major sources of trans fatty acids in the diet.

The omega-3 fatty acids are required as structural components of the brain and the retina of the eye in a child's early development. They are now known to effectively reduce inflammation and the tendancy of the blood to clot, and have also been shown to be useful in the treatment and prevention of heart disease, psoriasis and rheumatoid arthritis.

The hydrogenation of oil is the bubbling of hydrogen gas through the fat and this makes the oil solid at room temperature.

This hydrogenation process converts the unsaturated fats in the oil to saturated fats, and it is for this reason that the intake of hard margarines and products made with hydrogenated fats such as biscuits, pies, cakes and chips, should be restricted to a minimum. Soft margarines are only partially hydrogenated, and are therefore the preferred choice for spreads and baking.

Plant sterols, which are natural components of seeds, nuts and vegetables are known to have cholestrol lowering properties and have now been added in large quantities to a spread known as Flora Pro-Active.

These plant sterols prevent absorption of the bad LDL cholesterol and this results in an average of a 10% reduction in LDL cholesterol without affecting the good HDL cholesterol. It is known as functional food and it can help with better managing one's lifestyle, thereby preventing disease.

The latest dietary guidelines recommend that in addition to using far less fat, saturated fats should be replaced with monounsaturated or polyunsaturated fats. A more regular intake of the heart friendly omega 3 and omega 6 fatty acids is also strongly advised.

Here are a few guidelines to help you plan your daily fat intake:

*use a variety of fats and oils to ensure an adequate intake of different fatty acids.

*use liquid vegetable oils such as canola, sunflower, avocado or olive oil for cooking rather than margarine and butter.

*use a low oil mayonnaise or cottage cheese as alternative spreads for bread and crackers.

*grill, steam or bake food as a healthy alternative to frying.

*avoid foods rich in saturated fat such as sausages, pies, chocolate, donuts, cakes, biscuits, pastries and chips.

*low fat dairy products should be substituted for those with a full cream or double cream content.

*chill stews, curries, soups and gravies after preparation and remove the hardened fat from the surface before reheating and serving.

*do not overuse cooking oil - constant reheating of oil can set off a chemical reaction that can be damaging to your health.