Good fat vs bad fat
Different types of fats and oilsResearch has shown conclusively that we all need to eat a certain amount of fat everyday to stay healthy. Fats should not be excluded and fat free diets are not suitable for anyone. However, it is important to choose the right type of fat to eat. Saturated and trans fats (also known as the ‘bad’ fats) can have a damaging effect on health, whilst unsaturated fats (also known as the ‘good’ fats) have a positive benefit on health.
The diagram below shows the types of fats and oils and examples of foods they are found in.
To learn about the fats in commonly used oils click here.
The effect of different fats on blood cholesterol levels is shown below:
The ‘good’ fats
The ‘good’ fats are the monounsaturated and polyunsaturated fats like canola oil, olive oil, sunflower oil, and also the oils found in nuts and seeds, avocados and fish. These ‘good’ fats are generally liquid at room temperature.
It is important to eat some of these ‘good’ fats each day as they provide us with beneficial nutrients, like vitamins and antioxidants as well as the essential omega-6 and omega-3 fatty acids. The Heart Foundation recommends that we should replace saturated and trans fats in the diet with monounsaturated and polyunsaturated oils. In practice, this is as simple as swapping butter for a margarine spread; dipping your bread in extra virgin olive oil instead of spreading it with butter; using vegetable oils or margarine spreads in cooking rather than butter, and making cakes and muffins using vegetable oils or margarine spreads instead of butter.
Monounsaturated fatsMonounsaturated fats are a type of unsaturated fat. The unsaturated fats are commonly referred to as ‘good’ fats because they decrease cholesterol levels in the blood.
What are the health benefits of monounsaturated fats?
Monounsaturated fats help to reduce the risk of heart disease and diabetes. Populations that have traditionally eaten diets high in monounsaturated fats, such as those living in the Mediterranean region, have very low levels of heart disease when compared to other areas in the world.
Where do I get monounsaturated fats from?
The richest sources of monounsaturated fats are olive oil, canola oil and canola spreads, avocados, peanuts and peanut oil. Other sources include eggs, chicken, some fish, macadamia nuts and hazelnuts.
Polyunsaturated fatsPolyunsaturated fats are a type of unsaturated fat, so like the monounsaturated fats, they are known as ‘good fats’. Polyunsaturated fats can be subdivided into omega-6 and omega-3 fats, both of which are needed by the body to maintain health.
Omega-6 and Omega-3 are two essential fatty acids which are needed for good health. They cannot be made by the body and so must be provided by the foods we eat. A lack of these essential fatty acids can lead to deficiency symptoms, like dry and scaly skin, excessive thirst and impaired liver function.
Where do I get polyunsaturated fats from?
- The richest sources of polyunsaturated fats are vegetable and seed oils, like sunflower, soybean, corn and cottonseed oils, and polyunsaturated margarine spreads made from these oils. Other sources includes some nuts (walnuts, pecans) and seeds, oats, wheatgerm and ricebran.
Omega-3 fatsOmega-3 fats are a type of essential fatty acid. They are required for normal growth and development of the body and play an important role in infant brain and eye development. Research also shows that omega-3 fats have beneficial effects on maintaining a healthy heart, preventing the development of type 2 diabetes, alleviating the negative symptoms associated with rheumatoid arthritis and possibly slow down the growth of cancer cells. Omega-3 fats also help to regulate many processes in the body such as blood vessel and muscle activity, as well as the production of hormones.
Where do I get omega-3 fats from?There are two types of omega-3 fats in foods:
- Short chain omega-3, or alpha-linolenic acid (ALA), found in canola oil and canola spreads, walnuts, pecans and linseeds
- Long-chain omega-3, or eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA), found in fish and fish oils.
The ‘bad’ fats
Saturated fats and trans fats are the ‘bad’ fats found in foods as they have been shown to raise blood cholesterol levels and lead to an increased risk of developing heart disease. Too much saturated and trans fats in the diet can also lead to diabetes, some cancers and even obesity. Examples of foods containing high amounts of saturated and trans fats include animal fats like fatty meats, chicken skin, butter, cream, ice cream, full cream dairy foods and also the fats found in biscuits, pastries, cakes, coconut milk and palm oils. These ‘bad’ fats are generally solid at room temperature.
It is important to try as much as possible to limit the amount of saturated and trans fats you eat each day. According to the latest National Nutrition Survey, Australians are eating around 40% more saturated fat each day than is recommended for heart health.
Australian margarine spreads typically contains 65% less saturated fat than butter so making the change from butter to margarine spreads on your daily toast and sandwiches is an easy way to reduce the saturated fat your family consumes – in fact the Heart Foundation calculates that if you switched from using butter to a margarine spread on your toast and sandwich each day, you would eat 2.85kg less saturated fat each year!* (*Based on a daily 20g serve)
Saturated fatsSaturated fats are the ‘bad’ fats that increase blood cholesterol levels. They are usually solid at room temperature and are the main type of fat in butter, cream, ice cream, fatty meats, chicken skin, cakes, biscuits, pastries, confectionery and fried fast foods. Coconut and palm oil, although they are from plant sources, are also high in saturated fat.
How much saturated fat should we limit ourselves to each day?
- Global dietary guidelines recommend that no more than 10% of our daily energy intake should come from saturated fat. For an average adult, this equates to less than 20 grams of saturated fat per day.
How much saturated fat is in foods?The table below shows the average saturated fat content of some foods:
Butter and other animal fats contains high amounts of saturated and trans fat which can raise cholesterol levels in the blood thereby increasing the risk of developing heart disease. High cholesterol levels in the blood encourages more fatty buildup inside artery walls which causes the arteries to become clogged over time, leading to heart disease.
Trans fatsTrans fats are now being recognised as being even more harmful to heart health than saturated fats as they not only increase LDL-cholesterol (‘bad’ cholesterol) but they also decrease the protective effects of HDL- ‘good’ cholesterol in the body. Despite this, saturated fat is still the key issue in Australian’s diet.
All margarine spreads available in Australia are now virtually free of trans fats (containing <1% trans fats) , whereas butter contains 3% to 4% trans fats. It is advisable to eat as little trans fats as possible for healthy cholesterol levels and to keep the heart and blood vessels functioning normally.