Fats [Glossary]

Fats [Glossary]

Many fats are good for us and we need them in our diet. The term includes ‘oils’ which are fats that are runny at room temperature. It may surprise you to find out which fats are ‘good’ and which are ‘bad’. Read on!

Main glossary

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We need fats in our diet!

Fats are used for energy, to make cell membranes, and as a supply of vitamins A, D, E and K.

What are fats?

Fats are made from three fatty acid chains held together by a glycerol molecule. Fats in your fat cells are in this form, but when they need to move around the body (in the blood stream and lymph) the glycerol detaches and releases the fatty acids which are small enough to pass through cell membranes.

Low fat? No!
A low fat diet is a very bad idea; however, be choosy about which fats you do eat.

Saturated fats

Saturated fatty acid chains are less flexible, so foods containing mostly saturated fats tend to be solid at rooom temperature. They are the most stable kind and are best for cooking with.  Saturated fats are essential to health and are not bad for you.

Mono-unsaturated fats

Mono-unsaturated fats have one spare ‘bond’, so are more flexible. Olive oil has a high proportion of these fats.

Polyunsaturated fats

Polyunsaturated fats have two or more spare bonds, and foods high in these are usually liquid at room temperture. These are the worst fats for cooking with as they are unstable when heated and can form harmful transfats.  Omega 3 and omega 6 oil are polyunsaturated and good for health, but we need to be careful to have no more than 1-3 times more O-6 to O-3. The use of vegetable oils should be kept to a minimum because they are high in omega 6 and we only need a bit – it’s better to eat the seeds instead.


Transfats can occur naturally (in dairy products, for example) and they are fine. However, processed foods contain artificially-made transfats and these are implicated in various health issues. It’s best to make your own meals from scratch and then you know what is going into them! Overheating fats in cooking (eg, to smoking point) can create the harmful types of transfats too.

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