5
An introduction to fat
monounsaturated and polyunsaturated, Fatty acids can be saturated,
depending upon their structure (a monounsaturated or
Why do we need fat?
combination of carbon atoms with hydrogen polyunsaturated depending on
Most people automatically think of fat as ‘bad’
atoms attached – see the illustration right). how many double bonds there are
but our bodies can’t function properly without
some fats – or fatty acids, to be more accurate.
Each of these fats behaves differently
They are an energy source and play a crucial
in the body. Saturated fat is so called
role in all cell membranes – the coat that
because it is saturated with hydrogen
surrounds every cell in our bodies.
atoms. The more saturated it is, the harder
it is and usually solid at room temperature,
Fatty acids help carry cholesterol and when
such as lard and butter. Unsaturated fats
Saturated fatty acid molecule
levels are high, a small amount of good
such as olive and sunflower oil tend to be
(polyunsaturated) fat can help to carry it off for
liquid at room temperature and elastic,
disposal, rather like bin men! When the bin
vital for membranes, eyes and the brain,
men go on strike, rubbish accumulates in the
for example.
streets and it’s much the same inside the body
– too much bad (saturated) fat causes rubbish
Trans fats
(cholesterol) to be deposited in your arteries
Another type of unsaturated fatty acid,
Monounsaturated fatty acid molecule
and raises the risk of heart disease and stroke.
called trans fat, is largely industry-made
through a process called hydrogenation
Fatty acids are needed for healthy hair and
– adding hydrogen to low-quality
skin, they protect our organs, keep our bodies
vegetable oils to turn them into butter-
insulated and our brains are largely made up like substitutes with a longer shelf-life.
of them. We need fatty acids to carry certain These hydrogenated fats behave more like
vitamins from food into our bodies and without saturated fats and have no health benefits
some fats in our diet, we couldn’t function! – in fact, they’re extremely unhealthy. They
Polyunsaturated fatty acid molecule
raise ‘bad’ cholesterol levels in the same
The different types of fat way as saturated fats but more so. Health
Here’s the technical bit! Fatty acids authorities worldwide recommend that you
Single bond Hydrogen
come in three categories – saturated, avoid trans fats entirely. Double bond Carbon
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