Dietary fat is one of the three key macronutrients and an essential part of your diet. However, although some types of fats are healthier than others, they are all high in energy, so it is important to monitor the amount and type of fats included in your daily diet.
Fats play many roles in the body, particularly during metabolism. Your body can produce most of the required fats. Fats are also important in the enjoyment of food, improving its taste and feeling of satisfaction.
The sum of all chemical changes that take place within an organism to maintain growth and development and convert food into energy and building blocks.
All fats are high in energy, providing 37 kilojoules (kJ) per gram. In comparison, proteins and carbohydrates - the other two macronutrients that act as building blocks and sources of energy in the body - provide around 17 kJ.
It is difficult to maintain a healthy weight while eating high amounts of fats, particularly if you are not very physically active. Carrying extra weight (or being obese) is associated with an increased risk of a number of serious health conditions, including heart disease and type 2 diabetes.
Dietary fats shoul make up between 20-35% of all the energy you consume. It is also important to eat the right types of dietary fat.
A class of diseases that involves the dysfunction of the heart and/or the blood vessels.
There are a number of different fats in food and it helps to know a little about their chemistry to understand why they can have such different effects on your health.
Triglycerides are the most common type of fat found in foods. They get their name because they consist of one molecule of glycerol combined with three molecules of fatty acids (fats). It is the differences between the fatty acids in triglycerides that are important for your health.
In saturated fatty acids (SFAs) (or saturated fats), the carbon atoms of the fatty acid molecules attach to as many hydrogen atoms as possible - and so are 'saturated' with hydrogen. Therefore, due to their chemical structure, saturated fats tend to be solid at room temperature. They are found in:
Saturated fats can be produced within the body, so there is no actual need to consume them. However, because they are present in meats and full-fat dairy foods and are also often used for baking or frying, they are found in a wide range of products, particularly biscuits, cakes, pastries and fast foods such as hot chips, pizzas and burgers.
Unfortunately, when you eat saturated fats, they can increase the amount of harmful low-density lipoproteins (LDLs), which contain more cholesterol and triglycerides than protein, in your bloodstream. This can lead to blockages in blood vessels and an increased risk of heart disease and conditions such as heart attack and stroke.
Adults should limit saturated fat to no more than 10% of their daily energy intake.
To do this you can:
You do not have to cut out your favorite treats altogether, but it is important to remember they are treats. Only eat them occasionally and keep the serving size small.
Foods high in saturated fats can include foods such as chips, pizza and dairy products.
The mono-unsaturated fatty acids (MUFAs) contain one double carbon bond in the fatty acid molecules, so they have slightly fewer hydrogen atoms and are therefore called 'unsaturated'.
MUFAs tend to be liquid at room temperature and are found in:
MUFAs are produced within the body, but they may offer some health benefits, particularly when they are used instead of saturated fats.
Polyunsaturated fatty acids (PUFAs) contain two or more carbon bonds in the fatty acid molecules. This means they have fewer hydrogen atoms than MUFAs and so are called 'polyunsaturated'.
There are two main types of PUFAs: omega-6 and omega-3. The body cannot make these fats so they need to be consumed as part of your diet. PUFAs can help to reduce the levels of harmful low density lipoprotein (LDL) cholesterol in your bloodstream and therefore help to protect you from heart disease. Omega-3 PUFAs can also help to lower inflammation in the body.
There is ongoing research and debate about what is the healthiest balance of omega-6 and omega-3 PUFAs in the diet. In western diets, people tend to consume much more omega-6 than omega-3.
Omega-6 PUFAs can be found in:
Omega-3 PUFAs can be found in:
Compared to those obtained from fish sources, the body finds it more difficult to use omega-3 PUFAs from plant sources such as nuts, oils and seeds.
Foods high in unsaturated fats include nuts, avocado and fish.
Trans fats are polyunsaturated fats that are chemically changed by a process called partial hydrogenation. This is sometimes done in the production of processed foods because it means that this type of fat is less prone to spoiling and easier to cook with.
Trans fats can be found in:
Even more than the saturated fats, trans fats can increase the levels of unhealthy LDLs in your blood, leading to an increased risk of heart disease.
It is recommended that people minimize their consumption of trans fats. You can do this by checking the levels of trans fats on the packaging of processed foods that you buy and choosing options that are low in trans fats.
For a healthy option during cooking, use oils that are rich in unsaturated fats, such as sunflower and canola.
Cholesterol is a fat that is produced by animal cells and performs many important functions in the body, including:
Cholesterol is also found in all foods made from animal products, particularly in eggs, seafood, fatty meats and full-fat dairy products.
The body can produce cholesterol, so it is not necessary to consume it as part of your diet. Consuming cholesterol can increase its levels in the blood, although not as much as consuming saturated or trans fats.
Cholesterol can pose a risk to health because of the way it is transported in the bloodstream.
Cholesterol containing LDLs are the main form of cholesterol in the blood. When levels are high, it can cause blockages in blood vessels that can block blood supply to vital organs.
However, not all cholesterol is harmful. In contrast with LDLs that have a higher composition of cholesterol than protein, high-density lipoproteins (HDL) contain 50% protein in addition to cholesterol and triglycerides. These proteins also circulate in the bloodstream. They help to move cholesterol and other fats to the liver for disposal, hence helping to reduce risk of artery blockages and development of heart diseases.
Most healthy people do not need to avoid cholesterol-rich foods such as eggs and seafood, which in moderate amounts are very nutritious and part of a healthy diet. It is more important to limit the amount of saturated fats and trans fats that you consume.
You can help to keep your blood cholesterol levels healthy by:
Phytosterols (also known as plant sterols) are fats that are very similar to cholesterol, but are produced by plants. When phytosterols are consumed, they reduce the amount of cholesterol our bodies can absorb, but are not easily absorbed themselves.
They can be found in:
In an average diet, these sources only provide a small amount of phytosterols - not enough to significantly affect blood cholesterol levels. However, higher levels of phytosterols can be added to foods such as margarine that, when consumed in recommended amounts, can help to lower your blood cholesterol levels. Your doctor can discuss whether foods fortified with phytosterols are appropriate for you.
A fluid made in the liver and stored in the gall bladder.
A class of diseases that involves the dysfunction of the heart and/or the blood vessels.
The membrane that separates the cell from its outer environment, which regulates the flow of material into and out of the cell. It is composed mainly of fats, with embedded proteins contributing important regulatory functions.
A chemical substance secreted in one part of an organism and transported to another part of that organism, where it has a specific effect.
A vitamin that is important for the health of bones and teeth as it promotes absorption of calcium from the diet.
Proteins that combine with and transport fats in the blood. About 70% of cholesterol fat is transported by these proteins. High levels of low-density lipoproteins can lead to deposits on walls of arteries, leading to atherosclerosis.
An alcohol that has multiple uses in medicine, such as a skin moisturizer, as eye drops or as a laxative to treat constipation.
You can enjoy foods that contain fats as part of eating a healthy, balanced diet by:
Moderate amounts of different fats can be a part of healthy meals.