There has been a lot of debate in the media recently about what kinds of fats can be considered ‘healthy’, so it can be difficult to know what to include in your diet.
Firstly, it is important to note that our bodies need fats to function. They are a vital source of energy and are partially responsible for the development of our cells, lining our nerves, producing hormones, absorbing key vitamins and helping sustain body temperature.
Despite this, some fats can be bad for your health in the long-term. This is because certain fats are made by our bodies, while others are not. We should get the fats we don’t make from our diets, but should avoid the fats we do make.
However, having too much fat of any kind can lead to weight gain and health problems in the future. The best thing you can do for your health is to eat less fat overall and replace any ‘bad’ fats with ‘good’ fats.
In this article, you will learn about the effect of ‘bad’ fats on your cholesterol, the difference between ‘bad’ fats, and ‘good’ fats and tips for lowering your cholesterol levels.
Cholesterol is a type of fat in our bodies. You produce cholesterol naturally and like other fats, it aids many functions in the body.
There are two types of cholesterol: LDL and HDL. Both are necessary for your body’s function.
LDL cholesterol carries fat molecules to the cells and is thought of as the 'unhealthy' cholesterol. This is because it can build up in your blood, leading to blockages in your arteries.
HDL on the other hand, helps remove LDL from the body, lowering your cholesterol levels and the risk of fat build-up.
The main cause of high cholesterol is eating too much fat, especially the trans and saturated varieties.
According to the NHS, adults should have no more than 70g of fat daily.
Find more information on high cholesterol levels in our Health A-Z
‘Bad’ fats increase levels of ‘unhealthy’ cholesterol and triglycerides far more than ‘good’ fats.
There are two types of fats which are frequently categorised as unhealthy. These are saturated fats and trans fats.
Trans fats increase levels of triglycerides and harmful LDL cholesterol, and can even reduce your levels of helpful HDL cholesterol.
They are proven to be harmful and should be avoided altogether.
Some trans fats come from natural sources but most are artificial.
Artificial sources of trans fats include:
- Cakes (especially with frosting)
- Margarine (stick and tub)
- Fried fast foods
- Frozen pizza
- Breakfast sandwiches
- Sweets containing cream
- Microwave popcorn
- Sweet breads (particularly those with a ‘flaky’ texture)
It will not always say on the label if a product contains trans fats. Manufacturers are allowed to list 0g of trans fats if their product contains under 0.5g per serving. Small amounts can build up when you eat several servings at once.
You should check product ingredients for partially hydrogenated vegetable oils or shortening as these are a good indication of trans fats.
Naturally, trans fats can be found in small amounts in animal products like cheese, cream, beef, lamb or mutton.
It is best to limit the amount of trans fats you eat as they have no health benefits.
Saturated fats have long been considered bad as they can cause a rise in LDL cholesterol.
But, that does not mean we should eat more of them. There is still more research supporting the health benefits of eating unsaturated fats instead of saturated fats.
We should also be careful of what we replace saturated fats with.
Some research has shown that eating highly processed carbohydrates, or those containing white flour ( e.g. white bread, rice or pasta) increases your risk of heart disease even more than saturated fats would.
Therefore, try to replace saturated fats with unsaturated alternatives, and base your meals on starchy, wholegrain carbs, rather than the simple, highly processed varieties.
Saturated fats can be found in numerous foods, ranging from animal products to junk foods like cakes, biscuits and deep fried takeaway foods.
Animal products that are high in saturated fats include:
- Dairy products (e.g. milk, cheese, butter)
- Fatty, red meats (e.g. pork, lamb, beef)
- Processed meats (e.g. salami, sausages, chicken skin)
Plant products that are high in saturated fats include:
- Palm oil
- Cooking margarine
- Coconut products (e.g. oil, milk, cream)
You can find tips on eating less saturated fat in our Health A-Z
Unsaturated fats are considered ‘good’ for health. There is substantial proof dating back to the 1960s, that unsaturated fats have more health benefits than saturated fats.
Unsaturated fats have been linked to improved heart health. They can increase your levels of ‘good’ cholesterol, or HDL cholesterol, which helps your body get rid of ‘bad’ cholesterol. They can also lower your triglycerides.
There are two broad categories of ‘good’ fats: monounsaturated and polyunsaturated fats.
To lower your risk of health conditions like heart disease, you should still eat less of all fats, but replace ‘bad’ fats with ‘good’ fats where you can.
Monounsaturated fats are liquid at room temperature, but start to harden when chilled. Good sources of monounsaturated fats include:
- Olive oil
- Peanut oil
- Canola oil
- Most nuts
- Sesame oil
- High-oleic sunflower oil
- High-oleic safflower oil
You can also get some monounsaturated fats from animal sources like red meat, but there is research suggesting it is better to get unsaturated fat from plants rather than animals.
Polyunsaturated fats are essential fats, meaning your body does not make them, so you must get them from your food.
There is more research supporting the benefits of polyunsaturated fats compared to monounsaturated fats.
There are also two types of polyunsaturated fats: omega-3 and omega-6.
A good sources of Omega-3 is oily fish, like:
You can get Omega-6 from vegetable oils in foods like:
- Flax seeds
- Sunflower seeds
- Corn oil
- Soybean oil
- Safflower oil
There is more evidence supporting the health benefits of omega-3 polyunsaturated fats.
Causes of high cholesterol
The main cause of high cholesterol levels is a diet too high in fats, especially saturated and trans fats.
Other possible factors include:
- A lack of exercise
- Drinking large amounts of alcohol regularly
- Obesity and smoking
- Long-term conditions (e.g. kidney disease, liver disease and hypothyroidism)
- Genetics (e.g. conditions like familial hypercholesterolemia which can cause high cholesterol despite a healthy lifestyle)
However, it is more likely that high cholesterol is caused by diet than these other factors.
How to test your cholesterol levels
There are no symptoms to indicate that you have high cholesterol levels, but you can have a blood test to check.
You may be asked to have a fasting blood test which means not eating for 10–12 hours before your test.
If you are concerned about your cholesterol levels, you should make an appointment with your doctor.
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If you live in the UK, you can test your cholesterol levels at home with Thriva
How to lower your cholesterol
There are several steps you can take to lower your cholesterol level naturally. You should first aim to change your lifestyle by improving your diet, exercising regularly and quitting smoking.
Lowering your cholesterol levels with a better diet can be achieved by:
- Trimming off excess fat on meat and and choosing leaner cuts of meat
- Grilling, steaming or baking foods instead of frying or roasting
- Drinking semi-skimmed or skimmed milk instead of whole milk
- Looking at food labels and choosing food items that have lower fat contents
- Swapping snacks like chocolate, sweets and pastries with healthier options, such as a small handful of unsalted nuts or fruit
Find out more about lowering your cholesterol in our Health A-Z
Fats are an essential part of your diet. They are involved in many important processes in your body, from providing energy to lining cells.
Most of the fats you eat should come from unsaturated sources - or ‘good’ fat - as it is not made by our bodies. There is more evidence for its health benefits than there is for saturated and trans fats, or ‘bad’ fats.
Ultimately, eating too much of any fat can lead to weight gain and health problems, so try to stick to the recommended daily limit.
You should also avoid eating too many simple carbohydrates as these are worse for your health than saturated fats.
If you are concerned about your cholesterol levels, you can speak to your doctor. They can offer you a blood test and recommend treatments or lifestyle changes if your levels are too high.
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If you're in the UK, try Thriva's at-home cholesterol test
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