Fats that are solid at room temperature contain Saturated fatty acids and come mainly from animal foods. They provide energy, cholesterol (which as well as being necessary itself, goes on to make hormones) and a food reserve in time of plenty for use in times of famine. It is this last property which causes a problem - we do not have much famine in this country so the built up reserves continue to build up causing obesity and high cholesterol levels, both of which contribute to ill health.

Oils are liquid at room temperature, contain unsaturated fatty acids and come mainly from plants and fish oils. They can be divided into two sorts, depending on their structure - Trans and Cis. Trans can be looked on as similar to saturated fatty acids - can cause heart problems, so again, not too much in the diet. Some foods labels give the amount of Trans-fatty acids as well as saturated fatty acids e.g. Stork margarine and some biscuits, so look out for them

Important Cis fatty acids are much in the news, namely omega 3 and omega 6 fatty acids and much research is ongoing, both on their functions and their interactions. Omega 3 is important in blood clotting, sperm formation, brain function and eyesight. Low levels are associated with depression and Alzheimer's, as well as other diseases. Fish oils contain high amounts of omega 3. Omega 6 fatty acids, found particularly in vegetable oils, also has important functions.

So, cut down on fats, especially the Trans -fats and try cooking with vegetable oils, - rapeseed oil has a good proportion of omega 3, and try to include oily fish - sardines, kippers, mackerel, herring, salmon or tuna at least once a week as a good step in the right direction to keeping well.