Fats explained: saturated, unsaturated and trans fats

Fat is an important part of a healthy diet and getting the right balance of different fats in your diet will help keep your blood cholesterol levels, weight and heart healthy.

You need fat in your diet to:

• give you energy
• help absorb the fat-soluble vitamins A, D, E and K from food
• make hormones
• provide essential fatty acids which the body cannot make itself.

How much fat should I be eating?

About one third (no more than 35 per cent) of the calories you eat should come from fat, according to recommendations from the UK’s Scientific Advisory Committee on Nutrition.

For women who are eating 2,000 calories per day and for men eating 2,500 calories per day, this is equivalent to a maximum of about:

• Women: 70g fat per day
• Men: 95g fat per day

All types of fat are high in calories. Each gram of fat contains 9 calories, which is more than double the number of calories in carbohydrates and proteins, which both contain about 4 calories per gram.

Eating the right amount of fat per day is important because eating too much can give you too many calories, which could lead to weight gain over time.

This is important because having excess weight, particularly around the waist, can put you at increased risk of having a heart attack or stroke.

But it’s not just about how much fat you eat – it’s also about the kind of fat you eat.

Some fats are better for your heart than others, so making smart choices can really help keep your heart healthy.

What are the different types of fat?

Foods contain 2 main types of fat:

• saturated fat
• unsaturated fat.

Most foods contain a mixture of both fats in different proportions. If a food contains more saturated fat than unsaturated fat it would be described as ‘high in saturated fat’.

Eating too much saturated fat can raise blood cholesterol, in particular ‘bad’ cholesterol, known as ‘non-HDL cholesterol’.

You may have heard ‘bad’ cholesterol also being called ‘LDL cholesterol’, but we now know that as well as LDL, other forms of cholesterol affect your heart.

Having a high non-HDL cholesterol level increases your risk of heart attack and stroke.

Eating less saturated fat and replacing some of the saturated fat in your diet with unsaturated fat can help lower non-HDL cholesterol levels.

There are 2 types of healthy unsaturated fats; monounsaturated fat and polyunsaturated fat (see below for more on these).

• Learn more about what your cholesterol tests results mean.

Which foods are high in saturated fat?

Both food from animals and plants contain saturated fat. These include:

Animal sources

• fatty meats and meat products
• butter, lard and ghee
• cream, sour cream, creme fraiche
• cheese and savoury cheese biscuits
• full-fat dairy products
• processed foods made from the above ingredients: biscuits, cakes, ice cream, chocolate, pizza, pies, pastries, burgers, sausages and other processed meat products.

Plant sources

• Coconut oil – comes from crushing the flesh inside coconuts. It’s often reported as being ‘healthy’ but there is no scientific evidence to support this. It contains about 86 per cent saturated fat. This is about one third more that butter at 52 per cent.
• Palm oil – comes from the fruit of the oil palm tree and contains nearly 50 per cent saturated fat. It’s mainly used in the manufacture of fat spreads like margarine and lower-fat spreads, some peanut butters and other processed foods. However, the overall saturated fat content in these fat spreads is much lower than butter and they are usually fine to eat.

Like butter, you should use coconut and palm oils sparingly, and opt for unsaturated oils like olive, rapeseed, or sunflower oil for daily use.

Always check labels on processed foods like spreads, biscuits and cakes to limit how much hidden palm oil and saturated fats you eat.

Eating fewer processed foods will also help to reduce your saturated fat intake.

How much saturated fat should I eat?

Less than 10 per cent of the calories we eat should come from saturated fats. This is equivalent to a maximum of about:

• Women: 20g saturated fat per day
• Men: 30g saturated fat per day

If you already have heart disease or are at high risk of heart disease, you may need to eat less than this.

Which foods are high in saturated fat?

The table below shows some popular foods that contain a lot of saturated fat and are considered ‘high in saturated fats’ and will show as red on nutrition labels on food products.

(Note: the values in this table are approximates)

Is all saturated fat the same?

All foods contain a range of different types of saturated fat – some we know can raise blood cholesterol levels, which in turn increase the risk of heart attack and stroke. But there’s less certainty about the health effects of other types of saturated fat.

For example, some research suggests that a type of saturated fat called stearic acid, found in meat and chocolate, does not increase blood cholesterol levels as much as other types of saturated fat.

However, this does not mean these foods are healthy to eat in large amounts. This is because meat and meat products may contain other saturated fats and a lot of salt, which can contribute to raised cholesterol levels and high blood pressure.

And when it comes to chocolate – the sort most of us eat contains a lot of other saturated fats and sugar too.

Other studies suggest that full-fat dairy milk, cheese and yogurt may not increase your risk of heart attack and stroke thanks to other nutrients they contain like calcium, potassium and phosphates. But butter and cream do not share this potential benefit.

However, as dairy foods make up about a quarter of the saturated fats we eat, reduced-fat options are better for those with high cholesterol, or those who have excess weight. Eating reduced-fat options mean you still get the calcium, but with less fat and fewer calories.

Overall, there’s not enough research evidence to say 1 type of saturated fat is better than another.

This is why the NHS recommends eating a healthy balance of foods and to reduce saturated fat by replacing some foods high in saturated fat with foods high in unsaturated fats, such as oily fish, nuts and vegetable oils.

Which foods contain unsaturated fat?

As mentioned earlier, replacing saturated fat with healthy unsaturated fats can help lower blood cholesterol.

There are 2 types of unsaturated fat: monounsaturated and polyunsaturated.

Monounsaturated fats are found in:

• olive oil and rapeseed oil (and fat spreads made from them)
• avocados
• olives
• nuts (and nut butters) such as almonds, hazelnuts, peanuts, cashews, Brazil nuts, pistachios
• sesame seeds and sesame paste (tahini).

Polyunsaturated fats can be further divided into 2 main types that are called ‘essential fatty acids’. They cannot be made in your body, so you need to get them from the food you eat:

• Omega-3 – oily fish including mackerel, salmon, trout, sardines, pilchards, kippers, and flaxseed/linseed (and their oils), rapeseed oil and walnuts.
• Omega-6 – sunflower oil, corn oil (and spreads made from them), and some nuts (walnuts, pine nuts and Brazil nuts).

When it comes to oils, rapeseed oil contains a unique combination of omega-6 and omega-3 polyunsaturated fats, which can help lower cholesterol levels if used to replace saturated fat. Olive oil and sunflower oil are also good choices.

All 3 oils are a good source of vitamin E, particularly sunflower oil.

How much fat is in different oils and fats?

Here’s a helpful list I've made to help you choose fats and oils with less saturated fat that are healthier options for daily use.

(Note: the values in this table are approximates)

• Learn more about which fats are best for cooking.

What are trans fats?

You might have heard the term ‘trans fats’ and are wondering what they are. They are found naturally in dairy foods and red meats, but only in small amounts, and are safe to eat.

But there’s another kind of trans fat that’s not so heart friendly.

These are artificial trans fats, made by adding hydrogen to vegetable oils - a process called ‘partial hydrogenation’.

This turns the oil solid at room temperature and gives foods a longer shelf life.

Like saturated fats, artificial trans fats can raise ‘bad’ non-HDL cholesterol, but they also lower ‘good’ HDL cholesterol levels, which can increase your risk of heart attack and stroke.

Partial hydrogenation was widely used in foods like margarine, fried food, take-aways, biscuits, cakes, pies and pastries.

But the process is no longer used to make fat spreads, and as a result our intake of trans fats is low in the UK and well within the recommended maximum of 2 per cent of calories.

But still look out for the term ‘hydrogenated fat’ or ‘partially hydrogenated fats’ or ‘hydrogenated vegetable oils’ in the ingredients list on food labels as these contain trans fats.

What is dietary cholesterol?

Some foods contain cholesterol, known as dietary cholesterol. For most people dietary cholesterol does not have a big impact on the cholesterol in their blood.

This means you can still enjoy foods that are low in saturated fat, but contain some cholesterol, such as:

• eggs (cholesterol is in the yolk)
• shellfish
• lean meat including offal.

However, some people who have been diagnosed with familial hypercholesterolaemia may have to limit their dietary cholesterol intake.

How do I know how much fat is in a food?

Nutrition labels on pre-packed foods have been designed to help you reduce the total amount of fat and saturated fats you eat.

Most supermarkets and major food manufacturers use them on the front of food packets. They are a colour-coded system showing whether foods are high (red), medium (amber) or low (green) in fat (total fat), saturates (saturated fat), sugar and salt.

You can use the colour coding to compare similar foods. If a product has more green or amber colours and less red, it should be healthier.

The amount of total fat and saturated fat in a portion of the food will also be written on the colour-coded label and will be an amount in grams (g). The percentage (%) below that number tells you how much this portion of food contributes to your daily intake.

For example, in the label below, 150g serving of this food contains 12.5g fat, which is 18 per cent of the 70g of fat that is recommended as a maximum in a healthy diet.

• Not sure what a portion is? Use our portion size guide to find out.

What do ‘lower fat’ and ‘low fat’ food labels mean?

If a food label states that the food is ‘lower fat’, ‘reduced fat’, ‘lite’ or ‘light’ it must contain at least 30 per cent less fat than the standard product.

For example, lower fat mayonnaise must contain at least 30 per cent less fat than regular mayonnaise. But beware that some lower fat foods (like mayonnaise) may still be high in fat and calories.

If a food label says ‘low fat’, the food must contain no more than 3 per cent fat (3g fat per 100g).

But beware, lower-fat foods like fruit yogurts can have added sugar which will increase the number of calories they contain.

If you are worried about how much saturated fat you’re eating, please speak to a healthcare professional.

• Try our simple food swaps to lower saturated fat intake.

What to read next...