It is now well known that a high-fat diet can cause many chronic health problems; what is perhaps less well known is that low or no fat diets bring their own set of problems.
Fats are composed of building blocks called fatty acids and there are three major categories of these: saturated, polyunsaturated, and monounsaturated. The classifications are based on the number of hydrogen atoms in their chemical structure.
Saturated fats
These are found mainly in animal products such as whole milk, cream, cheese, and fatty meats. They are also found in coconut oil, palm kernel oil, and vegetable shortening (lard). Very small amounts are required - not more than 10% of total calorie intake, and preferably less. Having said that, a little (organic if possible to avoid chemical residues) butter is a more natural food than margarine and is therefore preferable.
Polyunsaturated fatty acids (PUFA's)
These come in two main types which are known as Omega 3 and Omega 6. Generally speaking, more people are deficient in the Omega 3 variety. These are obtained from oily fish such as herring, mackerel, salmon, sardines, etc. and from walnuts, pumpkin seeds, and linseeds - foods which tend to be lacking in the average diet today.
The benefits of these fats are enormous as they are anti-inflammatory, protective, and speed up the metabolism to name but a few. The Omega 6 fatty acids are much more prevalent in the modern diet, being found in corn, soyabean, safflower and sunflower oils, although many people may have difficulty converting them into nutrients which can be used by the body. Ideally the two should be perfectly balanced in a ratio of 2:1 (Omega 3: Omega 6).
Monounsaturated fatty acids
These are found predominantly in olive oil. A good Extra Virgin olive oil is cold pressed and unrefined and it does not become damaged during cooking. It is also delicious in salad dressings and can be drizzled over bread as a healthier option to butter. It forms a large part of the 'Mediterranean' diet, which many believe to be the healthiest in the world.
Trans-fats
There are certain processes which will turn the beneficial polyunsaturated fatty acids into their damaging counterparts, the trans-fatty acids. The first and most common is hydrogenation. This is mainly used to turn oils which have already been bleached, deodourised, and refined into margarines which are cheap, spreadable, totally devoid of nutrients, but have a long shelf life.
The second is frying in polyunsaturated oils. The delicate chemical structure is easily damaged at high temperature and can interfere with the way in which our cells function.
When fresh oils are processed in this way, their molecules are damaged in such a way that the relevant receptor sites within the body are unable to recognise and utilise them. Not only that, they actually prevent the uptake of the essential fatty acids.
03/06/2009