Fats: Are They Good Or Bad For Us?
Article by Emer O’Connor
Whilst fats play an important role in our diets, the consumption of certain types of fat may be harmful to our health. Decreasing the amount of dietary saturated fat has been a recommendation for decades to help reduce the risk of diseases, such as coronary heart disease. The energy that is consumed from fats varies widely, however current recommendations from several organisations such as World Health Organisation and Dietary Reference Intake recommend a total fat intake between 20 and 35% of total calories (1).
What are fats?
Fats, also known as lipids, are a source of essential fatty acids that the body cannot produce itself, and are a major source of energy for the body. The remaining fat which is not used by your body cells or turned into energy is then converted into body fat (2). Additionally, unused carbohydrates and proteins can also be converted into body fat (3). Some vitamins such as vitamin A, vitamin D and vitamin E are fat-soluble and can only be absorbed from the help of fats (2).
There are three main types of fat found in food: saturated fats, monounsaturated fats and polyunsaturated fats.
Saturated fats
Saturated fats are usually solid at room and refrigerator temperatures, and is found in fatty cuts of meat, butter, full fat dairy products, some savoury snacks, biscuits, pastries, and palm/coconut oil. For people who consume a high diet in saturated fats and low in monounsaturated and polyunsaturated fats, this is often associated with a high risk of cardiovascular disease (CVD) or coronary heart disease (4).
Unsaturated fats
To prevent diseases like CVD, it is important to substitute your saturated fat intake by consuming more unsaturated fats. It has been noted by many health professionals the benefits of unsaturated fats which can be found in oils from plants and fish (2). There are two types of unsaturated fats – monounsaturated fatty acid and polyunsaturated fatty acid.
Monounsaturated fats:
From a chemical standpoint, monounsaturated fats contain a single double bond in the acyl chain and are usually liquid at room temperature and semi-solid at refrigerator temperature. These fats can help reduce poor cholesterol levels in your blood which may lower risks of CVD and strokes (4). Foods that contain high levels of monounsaturated fats are plant-based oils such as olive oil, sesame oil and canola oil.
Polyunsaturated fats:
A fatty acid containing two or more double bonds in the acyl chain and are liquid at room and refrigerator temperatures (3). Similar to monounsaturated fatty acids, when substituted from saturated fatty acid, polyunsaturated fatty acids can lower the risk of CVD and strokes. Dietary sources include soybean, corn and unmodified safflower and sunflower oils. There are two main types of polyunsaturated fats, omega-3 and omega-6 and some types of these fats cannot be produced by the body which illustrates how essential it is to include them in your diet. Omega-6 can be found in vegetable oils and omega-3 in oily fish such as salmon and mackerel (3). If you wanted to find out more information about the different types of omega fatty acids, we have a whole blog post which you can read here discussing these and where you can source them in your diet.
Trans fats
Trans fats are found in foods originating from ruminant animals, such as cows and sheep, and are also in foods containing partially hydrogenated vegetable oils (1). Similar to saturated fatty acid, trans fats can raise cholesterol in the blood and increase the risk of CVD. Due to the increased risk of diseases of industrial trans-fat, health experts recommend to lower total trans-fat intake to below 1% (1).
Fat-free products
When buying food is it important to look at labels on food packaging in order to cut down on total fat or saturated fat. Fat-free products such as yogurts, cottage cheese and dressings can help lower the consumption of fat in your diet. According to the NHS, for a product to be labelled lower fat it has to contain less than 30% than a similar product. For saturated fatty acids, fat free is 0.1 of saturates per 100g or 100ml and for total fat, fat-free is 0.5 of fat or less per 100g or 100ml (3).
Tips for reducing fat intake
Limit total intake of fats and oils by substituting saturated fats with unsaturated fat.
Avoid us butter, margarine, lard and coconut oils. If using butter switch to something similar such as Flora which is made from plants. One serving pack of reduced-fat or light spread for two slices of bread should be enough. (12)
If you’re a mayonnaise and sauce lover, switch to low-fat substitutes that are available in many stores or even better create your own homemade dressings with low-fat ingredients. It
Use vegetable oils such as oil and rapeseed oil. It is recommended that one teaspoon of oil per person when cooking is the correct amount to use. (13)
Cheeses are high in fat, so when selecting a cheese try pick from non-fat milk such as mozzarella. (14)
Avoid high-fat processed and ready-made meals.
This blog was written by Emer O’Connor, a current MSc student in Food, Nutrition & Health at University College Dublin. She studied her undergrad in Economics at University College Cork however, surrounded by family with health related careers, and a passion for nutrition and aiding people to live a healthier life, she decided to pursue her career in nutrition. Emer aspires to become a registered nutritionist in the future and particularly branch into clinical nutrition. Keep up with latest info on her LinkedIn account.
References:
(1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577766/
(2) https://www.nhs.uk/live-well/eat-well/food-types/different-fats-nutrition/
(3) https://www.sciencedirect.com/science/article/pii/B9780128218488000135
(4) https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/monounsaturated-fats