What are the differences between saturated and unsaturated fats?

Confused about fats? Renee McGregor explains all you need to know about saturated and unsaturated fats and how they differ

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The NHS defines saturated fats as ‘those found in many foods, both sweet and savoury. Most of them come from animal sources, including meat and dairy products, as well as some plant foods, like palm oil and coconut oil.’ There’s good evidence that replacing saturated fats with some unsaturated fats can help to lower cholesterol.


Found primarily in oils from plants and fish, unsaturated fats can either be polyunsaturated (sources include oily fish, vegetable oils and walnuts) or monounsaturated (as found in olive and sunflower oil, avocados, and most other nuts).

Saturated fats have been a pretty controversial topic in recent years, with many high profile medics now dismissing the previous work associating a high saturated fat diet with higher risks of cardiovascular disease.

Nutritional guidelines still recommend that saturated fats are kept to a minimum and should be replaced with unsaturated fats, whole grains and pulses in order to reduce the risk of heart disease.

The exception to the rule is dairy such as cheese, milk and yoghurt; while these contain saturated fatty acids, there’s good evidence to suggest that these particular fatty acids are actually protective towards heart health.

Butter versus olive oil: which is best?

Butter is the fatty component of milk, and is 80% fat, 20% water. It’s one of the most complex structures of all dietary fats as it contains more than 400 different fatty acids, including butyric acid, which recent studies have shown plays several beneficial roles in the gastrointestinal tract

Olive oil is the oil extracted from the fruit of the olive tree. The predominant fatty acid is oleic acid, which constitutes 73% of total fat content. Oleic acid is a monounsaturated fatty acid and has been closely linked
to reducing inflammation in the peripheral tissue.


Verdict: While both have a place in the diet, olive oil is the better choice in this instance due to the high saturated fat content of butter and potential risks link