W2B-022 Health - Environment-0.txt
The Fat We Eat

by Cherril Bremmer
It has been estimated that in the UK our present fat intake represents about 42% of our total energy intake, and is around 140g daily for an average adult.
Fat is necessary in the diet for the following reasons: 1. Fat represents the most concentrated form of energy available supplying about 9.3 kcals per gram. Carbohydrate and protein provide about 4.1 kcals per gram. 2. It imparts palatability to food and lubricates it so making eating and swallowing much easier. 3. Dietary fat is necessary for the absorption of fat-soluble vitamins. These normally occur associated with fat. If the diet was fat-free, absorption of these vitamins would be poor, even if they were taken as supplements. They will not be absorbed across the intestine wall unless they can travel with fat. If it is absolutely necessary to take supplements of fat-soluble vitamins (namely A, D, E and K), these are best taken with a meal, rather than on an empty stomach, so that fat will be available for their absorption. 4. All fats contain Fatty Acids, three of which are essential in the diet. This is because they cannot be synthesised in the body, so must be provided. To ensure an adequate intake of these essential fatty acids it is necessary to eat a variety of foods containing fat.

The amount of essential fatty acids required represents only around 5% of our total energy intake, and apart from a supply of fat-soluble vitamins, this is in theory, all we need. However, nature does not supply all the essential fatty acids or fat-soluble vitamins, in the required amounts, in any one food, so we need a variety of fats.

In Western society we generally consume excess fat for the principal reason that it makes our food more palatable, but the difficulty now facing us, is how to find an acceptable compromise between what is good for our health and what we have come to enjoy.

We must strike a balance between using enough fat to provide for our needs while suiting our tastes but without harming our bodies by over-indulgence.

Whilst the total fat in our food is important, of equal importance is the nature of that fat, which brings us to consider saturated, polyunsaturated and monounsaturated fats. The difference between these three types of fats is based on the chemical structure of the fatty acids they contain. All fats are composed of fatty acids in association with glycerol, but differences between them occur in the fatty acid fraction.

A fatty acid is composed mainly of Carbon, and Hydrogen, with a small amount of Oxygen. The carbon atoms form a chain linked together by chemical bonds.

In SATURATED fatty acids, each carbon is linked to the next by ONE bond and this renders the entire structure chemically stable.

In MONOUNSATURATED fatty acids, two of the carbon atoms in the chain are linked together by TWO bonds - called in chemistry a DOUBLE BOND. Since there is ONE double bond, the fatty acid is said to be MONO-unsaturated. This double bond renders the entire structure less stable than the saturated form, and more vulnerable to attack by other chemicals.

POLYUNSATURATED fatty acids have TWO or more double bonds in the carbon chain, so are even less stable and that much more vulnerable to attack.

In terms of the food we eat, these facts are significant for three reasons: 1. The vulnerability of the carbon chain of mono and poly unsaturated fatty acids makes them more susceptible to attack by digestive enzymes. That means they are more easily broken down in the body. 2. The double bond makes the unsaturated molecule more flexible so it is more easily carried in the human transport system. 3. Vulnerability inside the body, also applies externally so unsaturated fatty acids are more easily oxidised by atmospheric oxygen, a process which produces unwanted fat peroxides. For this reason an antioxidant must be added to fats containing unsaturated fatty acids to lengthen their shelf life.

It has been observed that a diet high in polyunsaturated fatty acids results in a lowering of blood cholesterol - the principal enemy of the heart and arteries.

Cholesterol is produced internally by the liver and is also present in many foods we eat. While it is advisable to reduce cholesterol intake, such a reduction does not necessarily result in a lowering of blood cholesterol. Studies have shown that the diet of Mediterranean people who use Olive oil, appears to be less harmful in terms of Coronary Heart Disease than the Northern European diet containing more saturated fats. Olive oil contains the monounsaturated fatty acid, Oleic Acid, which is thought to have certain advantages over polyunsaturated fatty acids.

The Government recommends that we reduce our total fat intake to between 30% and 35% of our total energy intake, and that fat 15% or less should be derived from saturated fats.

To accurately assess your present fat intake in relation to total energy intake is tedious and time consuming, but you can estimate this by noting the fat in grams, you consume each day. Most food labels now contain information on the fat content and if you add up the fat per portion and find it to be more than 80 grams per day (for a woman of normal weight) or 100 grams per day (for a man of normal weight), then you must reduce it.

If you aim for 70-80 grams per day of which 10-12 grams are from saturated fats, for a woman and 90-100 grams per day for men, of which 13-15 grams are from saturated fats that will bring you within recommended intakes.

When it comes to the beloved Ulster Fry:- 1. Grill bacon and sausage. 2. Use olive oil or polyunsaturated vegetable oil for frying. 3. Measure the amount of oil you use in a tablespoon, counting 11 grams for each. 4. Keep a note of how much oil you use and try to reduce this to a minimum. 5. Remember the advice of the Bible - to be moderate in all things - make it a monthly treat!
