Fats form an important part of our diet.
It is used by our bodies in order to build cell membranes, and is also an essential component in blood clotting, inflammatory response, vitamin absorption and muscle movement.
Fat is the richest source of energy at 9 kilocalories per gram whereas protein and carbohydrates only produce 4 kilocalories per gram.
- Adults are advised to eat no more than 70g of total fat and 20g of saturated fat on a daily basis. These are the current reference intakes (RI) for fats and offer a helpful guide to those wanting to watch what they eat.
- If we regularly consume excess energy, whether it be from fat, proteins or carbohydrates, we are at risk of becoming overweight or obese.
- Obesity has been linked with an increased risk of some diseases such as cancer.
What is the link between fat and cholesterol?
Too much fat can also raise our blood cholesterol levels which can contribute to heart disease.
Our body needs some cholesterol to build cell walls and produce vitamin D, bile acids and hormones. It is made in the liver and moved throughout the body via the bloodstream.
There are two types of cholesterol:
- low density lipoproteins (LDLs) which transport cholesterol to where the body needs it;
- and high density lipoproteins (HDLs) which return cholesterol to the liver for filtering.
Too much LDL can clog arteries with deposits of cholesterol (known as atherosclerosis) which can in turn restrict blood flow; whereas not enough HDL can mean that our body is unable to get rid of excess cholesterol via the liver.
- Unbalanced cholesterol levels put you at risk of heart disease and stroke.
- Those with high cholesterol may be advised to reassess their diet and lower their fat intake.
What are the different types of fat?
Each type of fat is identifiable by its differing chemical structure.
Good fats are those that are unsaturated. This includes fats that are monounsaturated and polyunsaturated. They are usually higher in essential fatty acids and are often liquid at room temperature (such as olive and rapeseed oil).
Examples of unsaturated fat sources include:
- oily fish (salmon, mackerel and sardines)
- sunflower and olive oil
Essential fatty acids including omega-3 and omega-6 fall into the ‘good’ fats category. Omega-3 fatty acids are beneficial for heart health as they prevent blood clotting and promote a healthy heart rhythm.
Good fat might be better for your heart health but it is important to remember that all types of fat, whether ‘good’ or ‘bad’ can lead to weight gain. Excessively energy dense food can end up being stored by the body as fat.
Bad fats on the other hand tend to be solid at room temperature (such as butter and lard). These are referred to as saturated for trans fats.
Examples of items typically high in saturated fats include:
- fatty meats and processed meat products (for instance sausages and pies)
- butter and lard
- cakes, biscuits and pastries
- cream and ice cream
- sweet confectionary and chocolates
- coconut and palm oil
Saturated fats have been found to increase the amount of LDL cholesterol in our blood. As mentioned above, this can lead to the furring of arteries and constriction of blood vessels.
Trans fats are man-made, produced using a process called hydrogenation. This technique allows certain oils to be stored in a solid form and avoid becoming rancid. These types of fat have typically been used in biscuits, cakes and fast foods.
Trans fats in particular are thought to be detrimental to our health. They have been found to increase levels of LDL cholesterol while also lowering the amount of HDL cholesterol. According to a study carried out by Harvard University, for every two percent of trans fats consumed by a person on a regular daily basis, this person will increase their risk of heart disease by 23 percent.
These alarming findings prompted the UK food industry to take action. Numerous food manufacturers lowered the amount of trans fats being used or completely removed them from their products.
How to reduce your intake of saturated fat
There are a number of measures someone can take to lower the presence of saturated fat in their diet. These include:
- selecting lean meat products
- removing skin from poultry
- trimming off any visible fat on meat before cooking
- swapping full fat dairy products for lower fat alternatives
- reducing intake of high fat foods including processed foods, fried foods, cakes and sweets.
Those who need to lose weight due to health concerns may need to limit their overall fat intake, but pay special attention to saturates while doing so.
Those who are struggling to lose weight on their own and whose health may be at risk should seek advice from their doctor. In some cases, licensed prescription treatments can help people lose weight when employed as part of a controlled weight loss programme.