What’s the deal with fat? It’s actually vital for good health…

You might assume that eating fatty foods will lead to gaining body fat, however fat is one of the three macronutrients needed by the body, alongside carbohydrates and protein[1].

Fat doesnt always get a good rep though. However, there are a multitude of reasons why the right kind of fat is essential for good health.

Here is a selection of scientifically backed reasons as to why we need to include fats in our diet…

What is fat?

Dietary fats are found in a multitude of different foods, however, not all these fats provide benefits for the body. 

Fats can be split into two groups: unsaturated fats and saturated fats[2]. Saturated fats, the kind that we should generally be looking to cut down on, are found primarily in animal foods such as dairy and meats. This includes cheese, cream, sausages, and fatty cuts of meat[3]. Saturated fats can also be in a few plant foods such as coconut oil. 

Unsaturated fats on the other hand can be split into two groups: monounsaturated or polyunsaturated. The reason for the names? Chemically, monounsaturated fats are fat molecules with just one unsaturated carbon bond, whilst polyunsaturated fats are fat molecules that have more than one unsaturated carbon bond in the molecule[4]. 

Studies suggest that most of our dietary fats should come from unsaturated fats[5]. 

Monounsaturated fats are found in oils such as olive oil and rapeseed oils, as well as certain nuts (such as almonds and peanuts) and avocados. Polyunsaturated fats, which are split into omega-3 and omega-6, are found in oily fish such as mackerel, certain nuts (walnuts included), sunflower oil and flaxseed oil[6 & 7]. 

Another group of fats is trans fats. Around 80% of trans fats in the diet come from processed foods and oils[8] and studies have found that these trans fats are associated with health problems including coronary heart disease[9]. Eliminating or drastically cutting down on trans fats is wise[10].

The function of fats…

So why do we need fats? And specifically, why do we need unsaturated fats? 

Firstly, studies have found that a high intake of unsaturated fats is associated with a lower overall mortality when compared with the same number of calories from carbohydrates[11]. This in itself is a pretty impressive reason to ensure a healthy consumption!  

We also need unsaturated fats for heart health. Too much bad cholesterol – a fatty substance found in our blood[12] – can cause problems for the body however we do need some good cholesterol in the body as it helps protect the heart thanks to its anti-inflammatory and antioxidant effects[13] 

Levels of good cholesterol can be improved by eating unsaturated fats[14]. 

Women in particular also need a certain amount of this cholesterol to aid with hormone production, including the hormone oestrogen, a key sex hormone. Hormones are made from protein and fats, although oestrogen is also made from cholesterol[15].

An oestrogen deficiency can cause problems with bone density, plus it can lead to a reduced sex drive and an increase in belly fat[16]. There has also been evidence to suggest that certain fatty acids can improve fertility[17]. Plus for men, low fat diets have been shown to decrease testosterone levels[18]. 

Another key reason why we need to include dietary fats in our diet, is because they actually help with the uptake of certain vitamins. Research has found that a meal incorporating fat enhances the absorption of vitamin D3[19] as well as vitamins A, K and E[20]

Fat and portion control

A word of note when it comes to fats. Do keep in mind that dietary fats contain more calories per gram than the other macros, packing in 9 calories per gram as opposed to the 4 calories per gram in carbs and protein[21]. This just means that its a good idea to practice portion control with high fat foods. 


Confused on portions?

As a guide, a portion of oil is 1tsp[22], a portion of nuts is 30g[23], a portion of oily fish is around 140g, cooked[24] and portion of avocado is about half[25]. 

So next time youre preparing a meal, try to include a portion of unsaturated fats and enjoy the many benefits! 


[6] https://www.nhs.uk/live-well/eat-well/food-types/different-fats-nutrition/

[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551118/

[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551118/

[9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3551118/

[10] https://ncdalliance.org/why-ncds/risk-factors-prevention/trans-fats-elimination

[11] https://www.hsph.harvard.edu/news/press-releases/higher-consumption-of-unsaturated-fats-linked-with-lower-mortality/

[12] https://www.nhs.uk/conditions/high-cholesterol/

[13] https://www.heartuk.org.uk/cholesterol/hdl-cholesterol

[14] https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/

[15] https://www.health.harvard.edu/heart-health/how-its-made-cholesterol-production-in-your-body

[16] https://my.clevelandclinic.org/health/diseases/22354-low-estrogen

[17] https://pubmed.ncbi.nlm.nih.gov/26843151/

[18] https://pubmed.ncbi.nlm.nih.gov/33741447/

[19] https://pubmed.ncbi.nlm.nih.gov/25441954/

[20] https://www.sciencedaily.com/releases/2017/10/171009124026.htm

[21] https://my.clevelandclinic.org/health/articles/4182-fat-and-calories

[22] https://www.bhf.org.uk/informationsupport/support/healthy-living/healthy-eating/healthy-eating-toolkit/food-portions/oils-and-spreads

[23] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/nutrition/ask-the-expert/nuts-as-a-healthy-snack

[24] https://www.nidirect.gov.uk/articles/fish-and-shellfish

[25] https://www.nhs.uk/livewell/5aday/documents/downloads/5aday_portion_guide.pdf