Dietary Fat - What’s The Skinny?

March 03, 2020

Dietary Fats

Dietary Fat - What's The Skinny?

by our Sports Nutritionist Kate Shilland

Once considered the number one dietary enemy due to links between saturated fat and heart disease, fat has had a major comeback. Over the past decade, there has been a total U-turn, with high fat diets going mainstream, promoting butter in your coffee and sending sales of coconut oil and avocados through the roof. So, where’s the balance, what do we need to know about fats and how much should we be
eating?


What is fat?

Alongside carbohydrate and protein, fat is an essential macronutrient in the diet.
Nutritionally, fats have many important roles:

  • At 9 calories per gram, over double the amount of calories of protein or carbohydrate, it provides an essential source of energy.
  • Fat helps the body absorb vitamins A, D, E and K, these are fat-soluble, meaning they can only be absorbed with the help of fats. (low-fat diets can make you more likely to be low in these vitamins which can impact immunity and bone health).
  • Certain fats provide essential fatty acids, which the body cannot make itself. These play a key role in heart and brain health, hormone health and the correct functioning of our nervous system.

BUT, not all fats are equal: - Fats are subdivided into two main groups:
Saturated and Unsaturated - the difference between these fats is determined by their chemical structure, but in more practical terms, saturated fats are mainly animal based and are solids at room temperature (turning to liquid when heated), whilst unsaturated fats are typically liquid at room temperature

Saturated fats:
Saturated fats are considered to be ‘bad fats’ because they can raise blood cholesterol levels and increase the risk of heart disease. The latest UK dietary surveillance data shows people in the UK consistently eat too much saturated fat, which should be no more than 10% total daily energy intake.

Sources:
Meat products | Butter Ghee | Cheese | Cream | Sausages | Chocolate | Palm oil | Biscuits | Coconut oil

Trans Fats:
These are the ones that everyone agrees are bad for your health. They have been shown to reduce LDL cholesterol, increase the levels of triglycerides in the blood and increase the risk of heart disease. On labels, look out for ‘partially hydrogenated fat/oil or hydrogenated fat/oil. Food manufacturers have recently reduced the amounts in our food and we currently eat within recommended limits in the UK.

Sources:
Biscuits | Cakes | Pastries | Pies | Chips | Fried foods

Unsaturated fats:
Found in plant-based foods, they can be polyunsaturated or monounsaturated – considered the ‘good fats’ due to protective effects on heart health and cholesterol levels.

Sources:
Polyunsaturated (PUFA):  Sunflower oil | Nuts | Seeds 
Monounsaturated (MUFA): Olive oil | Rapeseed oil 
(PUFA and MUFA): Avocado | Pine nuts

Essential fatty acids: Omega 3 and Omega 6 fats
These are a type of unsaturated fat called ‘essential’ fatty acids (Alpha Linoleic Acid – omega 3) and Linoleic acid – omega 6) as the body cannot make enough. From these, we can make EPA and DHA. These are all essential for heart and brain function, cell signalling and maintaining healthy cholesterol levels.

Salmon | Mackerel | Sardines | Pilchards | Trout
Walnuts | Flax seeds | Pumpkin seeds
Rapeseed | Linseed oil | Soya Soya products | Enriched foods such as eggs and yoghurts

  • Aim for 2 portions of oily fish per week and a 25g portion nuts/seeds per day


How much?
Reference Intakes (RIs)) for energy, total fat and saturates

Women
 
 Men
Energy (Calories)
2000
2500
Fat (g)
70
95
Saturated fat (g)
20
30




It’s unusual to get universal agreement on nutrition but, from a health perspective, it is widely agreed that reducing our intakes of saturated fats and trans fats and replacing them with unsaturated fats, including essential fatty acids, is good for your health. As well as type, the amount of fat we eat is important and should be around 30% of our total daily energy intake. Getting into the habit of reading food labels will help you to make healthier choices and to find the right balance in your diet.

 

References

  • Mozaffarian D (2009)’ Health effects of trans-fatty acids: experimental and observational evidence’Europen Journal of Clinical Nutrition, 63 (S2), ppS5-S21. Doi:10.1038/sj.ejcn.1602973
  • NDNS: results form years 7 and 8 (combined) – GOV.UK
  • https://gov.uk/government/statistics/ndns-results-from-years-7-and-8 combined (Accessed: 14 Nov 2019)
  • McCance, R, AFRC Institute of Food Research, Public Health England, R.S of C (Great B. (issuing body) (2014) McCance and Widdowson’s the Composition of Foods, 7 th edn. RSC
  • Saunt & West(2019), Is Butter A Carb?, London, Piatkus; pp29-43
  • http://www.sacn.gov.uk/pdfs/sacn_trans_fatty_acids_report.pdf
  • http://www.sacn.gov.uk/pdfs/fics_sacn_advice_fish.pdf
  • Weichselbaum E, Coe S, Buttriss JB et al (2013) Fish in the diet: A review. Nutrition Bulletin 38(2):128-177
  • Department of Health (1991) Dietary Reference Values, A Guide. HMSO, London.
  • Department of Health (1994) Report on Health and Social Subjects No. 46. Nutritional Aspects of Cardiovascular Disease. Report of the Cardiovascular Review Group Committee on Medical Aspects of Food and Nutrition Policy. HMSO, London.

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