Watch: What does fat do and what is saturated fat?

There's lots of confusion when it comes to fat. Watch our animation to learn what fat does to your body, and get answers to common questions about saturated fat and which foods contain it.


What is saturated fat?

It’s not always clear what we should or shouldn't be eating to improve our heart health – especially when it comes to fats. Despite what you read in the media, our advice is clear – replace saturated fats with unsaturated fats and avoid trans fats. Saturated fat is the kind of fat found in butter, lard, ghee, fatty meats and cheese.

Eating a diet high in saturated fat is associated with raised levels of non-HDL (bad) cholesterol. This is linked to an increased risk of heart and circulatory disease. That’s why official recommendations emphasise the importance of reducing saturated fat in our diets. 

But just replacing saturated fat with refined carbohydrates, like sugary foods and drinks, won’t improve your health. Replacing it with unsaturated fats such as oily fish, nuts, or vegetable oils like rapeseed or sunflower oil, does seem to reduce your risk of heart attack and stroke.

Remember, though, all types of fat are high in calories, so eating too much can lead to weight gain. Being overweight or obese is a risk factor for heart and circulatory disease, and many other diseases.

What kind of fats are the healthy kind?

Vegetable oils are the healthy choice for frying and baking, and plant-based spreads, avocados or nut butters for sandwiches, toast and potatoes. These are healthier choices than butter or lard. Check food labels and compare the fat content in different products to help you choose ones that are lower in saturated fats. 

But remember, while this will help to lower your cholesterol level, we need to look at our whole diet to reduce overall risk. Many factors affect heart disease risk, not one food or nutrient alone. The Mediterranean diet is associated with reducing your risk of heart and circulatory disease. It includes plenty of fruit and vegetables, pulses, fish, nuts and seeds, and less butter, meat, full-fat dairy products and high-fat snacks, so it’s naturally higher in unsaturated fats and lower in saturated fats.

A jug of olive oil and some green olives

But surely fat from natural sources is better than manufactured products like margarine?

Margarine and low-fat spreads used to contain artificially produced trans fats, which, like saturated fat, can raise your ‘bad’ (non-HDL) cholesterol levels and lower ‘good’ (HDL) cholesterol levels. They can still sometimes be found in biscuits, cakes and pastries, especially in imported foods. However, in recent years most UK manufacturers have removed artificially produced trans fats from their products. Check the food label: if it lists partially hydrogenated oil in the ingredients, then it contains some trans fat.

Spreads made from vegetable oils contain healthy unsaturated fats – polyunsaturated and monounsaturated fats – whereas butter contains more saturated fat. A little bit of butter every now and then is fine. However, for everyday eating, replacing butter with a spread made from unsaturated vegetables oils (olive, sunflower or rapeseed) helps reduce the saturated fat in your diet, benefiting your cholesterol levels and therefore your risk of heart disease.

Check food labels and compare the fat content in different products to help you choose ones that are lower in saturated fats.

Are there "good" saturated fats?

Some research suggests that different types of saturated fat can have different effects on your risk of heart and circulatory disease. For example, stearic acid, a saturated fat found in meat and chocolate, doesn’t seem to affect cholesterol levels. But that doesn't mean these foods are healthy - all foods contain a range of different saturated fatty acids. The visible fat on meat and in processed meat does contain saturated fats known to increase cholesterol levels. Processed meat is also often high in salt, which can raise your blood pressure, a risk factor for heart attack and stroke. And most of the chocolate we eat in the UK is high in added sugar and fat. Eating too much can lead to weight gain, which will also increase your risk of many health conditions. 

At present, there isn’t enough evidence to choose one saturated fat over another – it’s better to swap them for oily fish, vegetable oils or nuts.

I've heard that grass-fed beef contains healthy fat, is this true?

Grass-fed beef generally comes from cattle that eat only grass and other foraged foods whereas conventional beef cattle often eat a diet that includes grains, such as corn. Although grass-fed beef is said to be leaner and contain more of the healthy polyunsaturated fats such as omega-3 fatty acids, there is limited long-term research to prove grass-fed beef is better for you. We do not recommend grass-fed or organic meat over other meats. If you are going to eat red meat, the most important thing is to choose the leanest type so you can limit the amount of saturated fat you eat.

What about coconut oil, isn’t that the healthy type of saturated fat? 

Coconut oil is about 86 per cent saturated fat, about one-third more saturated fat than butter (at 54 per cent). There has been speculation that some of the saturated fatty acid in coconut oil, lauric acid, may be better for us than other saturated fats. But so far there are no quality studies to indicate that coconut oil has the edge over oils we know are better for us, like rapeseed or olive oil. If you like the taste of coconut oil, then, as with butter, it is fine to use it every now and then. However, be careful not to overdo it, and use unsaturated oils as an everyday choice instead. 

 Jar of coconut oil and coconuts

Aren't nuts and olives healthy, do I have to worry about the saturated fat in those?

Nuts have a high fat content, so are high in energy (calories). In most nuts, the fat is mostly unsaturated: either polyunsaturated fats (walnuts and pine nuts) or monounsaturated fats (almonds, pistachios, pecans, peanuts and hazelnuts). There are some exceptions. Brazil nuts, cashews and macadamia nuts are higher in saturated fat, so only eat them occasionally. Chestnuts are lower in all types of fat and higher in starchy carbohydrate than other nuts. Nuts (apart from chestnuts) are also high in protein, making them a satisfying snack.

Olives are also high in monounsaturated fats, and compared with nuts they contain fewer calories, though they are high in salt. One olive contains about 5kcal, while a pecan contains 14kcal. As a substitute for foods high in saturated fat and sugar, such as biscuits, chocolates or cakes, olives or unsalted nuts can be a healthy snack choice. But watch your portion size to avoid consuming too much salt or fat, and choose unsalted nuts where possible.

Do I have to completely remove saturated fat from my diet?

It’s almost impossible to completely remove saturated fat from your diet. Instead, keep an eye on how often you eat foods high in saturated fat, watch your portion size and substitute for healthier options where possible. All fats are a combination of saturated, and mono- and polyunsaturated fatty acids. They tend to be classified by the fat that makes up the largest percentage. Olive oil is mostly monounsaturated (73 per cent), but still contains saturated fat (14 per cent), while butter is mostly saturated fat (54 per cent) but still contains monounsaturated fat (20 per cent).

The BHF has teamed up with rapeseed oil producer Borderfields to raise funds for research into heart and circulatory diseases. For every jointly branded bottle sold in the UK, Borderfields will donate 10p to the BHF, hoping to raise more than £50,000 in 2019.

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