The Department of Health recommends we consume no more than 30-35 per cent of our total calories from fat in food, but in reality we consume nearer 40 per cent. Both so-called invisible fats – those hidden in foods – and visible oils, spreads and meat fats contribute equally to our consumption.

Because fat is so rich in calories – there are 225 calories in 25 grams of fat, which is more than double the amount in the same weight of carbohydrate or protein – too much of it can result in obesity. Additionally, certain types of fat are more unhealthy than others and can increase the risk of some of the biggest killer diseases in the UK, such as heart disease and cancer.

Where does our fat come from?
In the UK, cakes, biscuits and desserts provide 19 per cent of our fat intake, along with dairy foods (15 per cent), soups and sauces (3 per cent), chocolate and fudge (3 per cent), oily fruits like olives (1 per cent), meat products (24 per cent), spreads such as butter and margarine (17 per cent), fish oils (3 per cent) and eggs (4 per cent).

Why do we need fat at all?
In spite of its unhealthy reputation, some fat is necessary in the diet to keep us in good shape. For instance, the body requires a minimum of 25 grams of fat to allow the absorption of the fat-soluble vitamins A, D, E and K and also beta carotene. Fats are especially important in the diets of children, who should never be advised to follow a reduced-fat diet while they are still growing.

There are different types of fat, which vary in their nutritional analysis. The two main types of fatty acid are saturated and unsaturated. The unsaturated fats are found in vegetable oils, fish and nuts and can be categorised as either monounsaturated or polyunsaturated; saturated fats come mainly from animal foods – examples are butter, lard and fatty meats.

The body can manufacture certain types of fat itself, but it cannot make some of the polyunsaturated fats and these must be obtained from food. For this reason they are called essential fatty acids. Omega-6 fatty acids are one of these, and they are needed to help the body to carry out a range of functions. Adults need an intake of around four grams of these omega-6 fats a day to stay in good health, although too much can be harmful.

The other essential fatty acids are called omega-3, found mainly in vegetable oils and oily fish, and the body generally requires less of them. They are needed for brain function and in research have been shown to help prevent blood from clotting, and therefore are thought to be important in the prevention of heart disease.

Which fat should we cut out?
The Government recommends cutting the saturated fat content of our diets to around 10 per cent of our calorie intake. Saturated fats are found mainly in foods of animal origin, although palm and coconut oils also have a high saturated fat content. A high intake is known to increase the risk of heart disease, so try to replace them with with healthier unsaturated fats.

Some fats are hardened artificially in the manufacturing process, which requires changing unsaturated fats into saturated. These are called trans fats. Research has suggested that these fats are unhealthy and can be as big a risk for heart disease as a high intake of saturated fats.