Fat is a source of essential fatty acids, which the body cannot make itself. Fats and oils are made up of molecules of fatty acids which can be saturated or unsaturated. 

Fat has a number of important functions in the body:

  • Fat is a valuable energy source
  • The membrane of every human cell is formed from a phospholipid bilayer – our fat consumption is reflected in our cells
  • Enables the absorption of fat-soluble vitamins, A, D, E, K
  • Certain fats are ‘essential’ and cannot be synthesised in the body – omega 3 and omega 6 fatty acids
  • Omega 3 and omega 6 are used for the synthesis of eicosanoids which are anti-inflammatory molecules


Good sources of fat: fish – salmon, mackerel, sardines, tuna, kippers, cold pressed oils, nuts/ nut butter – walnuts, hazelnuts, macadamia nuts, pecans, pistachios, almonds, seeds, avocado.


Saturated Fats: mainly found in animal sources such as meat and dairy products, however there are some plant food sources such as coconut oil. Eating too much saturated fats can be detrimental to your health, they can increase the ‘bad’ low-density lipoprotein (LDL) cholesterol in your blood which can increase the risk of stoke or heart disease. 

Foods high is saturated fats: fatty cuts of meat, processed meats (sausages), butter, ghee, lard, cheese, cream, soured cream, chocolate, biscuits, cakes, pastries, coconut oil and coconut cream. 


Unsaturated fats: mainly found in oils from plants and fish. Unsaturated fats can be monounsaturated or polyunsaturated. Aim to swap saturated fats for unsaturated fats to improve your health, lower your cholesterol levels and reduce the risk of heart disease. 


Monounsaturated fats: protect your heart health by maintaining levels of ‘good’ HDL cholesterol and reducing levels of ‘bad’ LDL cholesterol in your blood. 

Good sources of monounsaturated fats: olive oil, rapeseed oil and spreads, avocados, nuts (almonds, brazils)


Polyunsaturated fats: can also help lower your levels of LDL cholesterol and there are two types of polyunsaturated fats, omega-3 (alpha linolenic acid) and omega-6 (linoleic acid). These fatty acids are essential so they must be consumed through the diet as the body is unable to synthesise them. In the UK, dietary intakes of omega-6 are far higher than intake of long chain omega-3 fatty acids which are found in fish oils.


Fat and weight loss

Fat is the richest source of dietary energy available in the diet and so can readily contribute to weight gain. Foods that are high in fat provide a lot of energy, a gram of fat provides 9kcal of energy compared to carbohydrate and protein which provide 4k/cal of energy per gram. Fat may have a less filling effect than other foods such as protein and fibre. This means it is easier to consume an excess of energy if you’re eating a high fat diet. Any dietary fat that is not used is converted into body fat, as do excess carbohydrates and proteins, which can lead to weight gain. 


Tips for weight loss:

Reduce your intake of saturated fats which can raise your cholesterol and increase the risk of heart disease.

Aim to eat at least two portions of oily fish a week.

You may benefit from including an fish oil supplement in your diet.


Written by Bev Walton, BSc Nutritional Science

I achieved a First-Class Honours degree in BSc Nutritional Science, Nutrition Sciences from the University of Reading and now have over 35 years experience in all types of cuisine, dietary plans, recipe development, health and nutrition. I have been writing for over 10 years for magazines and websites as well as ghostwriting for ebooks, Kindle and fully published books. I’m also a proud member of the Guild of Food writers.

Bev Walton | University of Reading BSc Nutritional Science, Nutrition Sciences

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