Updated: Mar 7
Fat often has a negative meaning. There are plenty of low fat diets, people often want to reduce fat intake to lose weight or you can see innumerable 'low fat' products in your cornershop.
However fat is one of the macro nutrients the human body needs to function and perform at its best.
Is fat good or bad? What type of fat should you prioritise?
To answer those questions and have a better understanding to the impact of fat it is important to breakdown the definition and effects of the different types of fat.
Saturated Fat (SF) is one of the 3 natural sources of fat. It is mainly present in coconut oil, butter, cream, cheese and whole milk.
There are 9 calories in 1g of SF, like for any other type of fat (monounsaturated and polyunsaturated fat). But it has specific functions.
SF is a principal source of energy during aerobic activity (which is defined by the American College of Sports Medicine as 'any activity that uses large muscle groups, can be maintained continuously and is rhythmic in nature').
Which means that whenever you perform swimming, walking or runnning, from low to moderate intensity, SF stored in your body is used as fuel.
SF also plays an important role in the protection of vital organs. And so it does in transport of fat-soluble vitamins that will have an impact in protein utilisation.
If consumed in too large amounts SF have a high propensity to be converted into body fat, which gives it its bad reputation.
However, SF is considered as a vital nutrient that should be present in any healthy diet, and its composition and resistance to high temperatures make it perfect for cooking.
Monounsaturated Fat (MF), known as the first unsaturated fat, is considered as 'good fat'. You can find it in olive oil, chicken, beef, seeds, nuts, avocado and fatty fish such as salmon.
Its different shape make its functions different too. MF is used by the human body to protect the heart. It helps maintaining 'good' HDL (High-Density Lipoprotein) cholesterol and reduce 'bad' LDL (Low-Density Lipoprotein) cholesterol in blood.
MF also has a key role in muscle movement and helps inhibit inflamation.
Its composition makes it slightly reactive to heat and caution must be paid to not overheat it during cooking, which could make it unhealthy.
The Institute of Medicine recommends using them as much as possible, along with polyunsaturated fats, to replace saturated and trans fats.
Polyunsaturated Fat (PF), known as the second unsaturated fat, is composed of both Omega 3 and Omega 6 (the numbers refering to the distance between the beginning of the carbon chain and the first double bond).
You can find Omega 3 in sardines, salmon and mackerel and Omega 6 in rapeseed oil, corn, sunflower and some nuts. Most people get enough omega 6 in their diet, but it's recommended to have more omega 3.
PF is not produced by the body despite its necessity for the body good function.
PF helps building cell membranes and protecting nerves. It is needed for blood clotting, muscle movement and inflammation.
Trans Fat (TF) is made by heating liquid vegetable oils in the presence of hydrogen gas and a catalyst, a process called hydrogenation.
It can be found in cakes, cookies, pies, margarine and in most take away or ready to eat meals found in supermarkets.
Consumed in relatively small amounts, it does not present any real problems for your health. However, many modern food preparation methods result in an abundance of trans fats being formed and consumed.
TF is the worst type of fat for the heart, blood vessels, and rest of the body.
It raises 'bad' LDL and lowers 'good' HDL, creates inflammation, contributes to insulin resistance.
Its composition does not make it essential for human body and it is recommended to avoid it as much as possible.
Fat, an essential macro nutrient
Many of the problems associated with different types of fat are due to the fact that they make you fat.
Fat itself is not bad. It is even important for good body function.
As previously seen fat has innumerate benefits for the human body.
However caution must be paid to the amount of different types of fat consumed. Over eating fat can increase body fat and also impairs the vital body functions.
UK government recommends that 'men should not eat more than 30g of saturated fat a day and women should not eat more than 20g'.
In terms of Trans Fat 'adults should not have more than about 5g a day'.
Also the NHS website precises that 'people in the UK tend to eat a lot more saturated fats than trans fats. This means that when you're looking at the amount of fat in your diet, it's more important to focus on reducing the amount of saturated fats.'
How much fat should you consume
The UK government via the NHS website delivers a guideline regarding the amount of fat intake that is healthy or not.
It says that in terms of Total Fat, 17.5g per 100g is considered as high fat.
Low fat being 3g or less per 100g and 1.5g per 100ml for liquids.
Approximately Saturated Fat 5g per 100g is considered as high fat.
1.5g per 100g or 0.75g per 100ml being low fat.
Precious information that breaks cliches about fat and can be useful when it is time to pick up your next take away food or organise your diet.