Fat in a healthy diet

What is fat and what are the different types?

Fats are an important part of a healthy, balanced diet. We need some fat in our diets to help us absorb the fat-soluble vitamins A, D, E and K. Fats are also a source of essential fatty acids, which the body cannot make itself.

However, too much fat in our diet can be bad for our health. All types of fat are high in calories and provide 9kcal per gram, more energy per gram compared to protein and carbohydrate, which contain around 4kcal per gram, or alcohol (around 7kcal per gram). Eating a lot of fatty foods can make it easy to consume more calories than we need, and over time, this can lead to weight gain.

Fats in foods can either be saturated or unsaturated depending on their chemical structure. Most foods that contain fat contain a mixture of both saturated and unsaturated fats in different proportions, but we would normally describe a food as being high in saturated or unsaturated fat depending on which type they are a richer source of.

Although there is a lot of debate about the health effects of fats in the diet, we have many studies that show that replacing saturated with unsaturated fats in the diet can help reduce our blood cholesterol. This is important because high cholesterol is one of the risk factors of heart disease – so it is good to be aware of the balance of your saturated and unsaturated fat intake. Obesity is also a risk factor for heart disease, so weight management is important, and we need to be aware of the quantity of total fat in our diet. For a healthy diet, it is important to get most of our fats as unsaturated fats from sources like rapeseed or olive oils, nuts, seeds, avocados and oily fish.

Saturated fats

Knowing the kinds of foods that contain high amounts of saturated fat – and those that do not – is a good way to make choices when it comes to planning a healthy diet. While it’s not possible or necessary to eliminate saturated fat from your diet completely you will be able to make informed decisions as you shop and prepare meals.

Foods that are high in saturated fats include:

• fatty cuts of meat and processed meat products like bacon, sausages and salami
• cheese, especially hard cheese like Cheddar
• cream, crème fraiche and soured cream
• butter, ghee, suet, lard
• coconut oil and palm oil
• coconut milk and cream
• ice cream
• cakes, biscuits and pastries, like pies, sausage rolls and croissants
• savoury cheese flavoured crackers or twists
• chocolate and chocolate spreads

It is best not to eat too many foods high in saturated fat. This is because too much saturated fat in our diet can raise cholesterol in our blood, which can increase the risk of heart disease and stroke. When it comes to fats like butter or coconut oil it is best to replace these with unsaturated types like vegetable or olive oils or spreads.

Unsaturated fats

Replacing saturated fats in our diet with unsaturated fats can help to maintain healthy cholesterol levels. As part of a healthy, balanced diet, it is best to choose foods that contain higher amounts of unsaturated fat and less saturated fat to reduce your risk of heart disease.

There are two types of unsaturated fats: monounsaturated and polyunsaturated fats.

Monounsaturated fats

Replacing saturated fats in our diet with monounsaturated fats can help to decrease levels of total cholesterol and harmful LDL-cholesterol.

Monounsaturated fats are found in:

• olive and rapeseed oils and spreads made from them
• olives
• avocados
• nuts and seeds such as almonds, Brazil nuts, hazelnuts, peanuts, pine nuts and sesame seeds and spreads or pastes made from them (like nut butter or tahini). The fat content of different types of nuts is shown in Table 1 on the right.

These foods are typical of the Mediterranean-style diet, which is associated with good heart health and a lower risk of heart disease.

Polyunsaturated fats

Replacing saturated fats in our diet with polyunsaturated fats can also help to lower ‘bad’ LDL-cholesterol. There are two main types of polyunsaturated fats: omega-3 and omega-6. 

Polyunsaturated fats are found in:

• some vegetable oils and spreads made from them (including corn, sunflower and sesame)
• flaxseeds, sesame seeds and sunflower seeds
• walnuts, pine nuts
• oily fish (including mackerel, salmon, trout, herring and sardines)

Omega-6 fats

One type of omega-6 fat called linoleic acid is an essential fatty acid, which means that our bodies cannot make it from other fats and so we must get it from our diet. Omega-6 fatty acids are found in vegetables oils (such as rapeseed, corn, sunflower) and some nuts. In the UK we typically get enough omega-6 fats in our diet.

Omega-3 fats

The most important omega-3 fats are the long chain omega-3 fats like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which may help lower our risk of heart disease, and also contribute to normal visual and brain development in babies during pregnancy. Oily fish such as salmon, mackerel, sardines and trout are rich sources of long chain omega-3 fats. Healthy eating guidelines in the UK advise we eat two portions of fish (2 x 140g) a week, one which should be an oily type.  However, we know that UK intake of oily fish is far lower than the recommended amount. Long chain omega-3 fats are also found in eggs and, in smaller amounts in meat.

You can also get omega-3 fatty acids from certain plant foods. Examples of plant food sources of omega-3 fats include: 

• some seeds (such as flax and chia seeds)
• oils (such as flaxseed, rapeseed)
• walnuts and walnut oil
• soybeans and soybean oil

However, these are a short chain omega-3 fats known as α-linolenic acid (ALA).  The body can convert short chain ALA to the long chain omega-3 fats but the efficiency of this process is unclear.

Supplements containing long-chain forms of omega-3 fats (including EPA and DHA) from microalgae are also available that are suitable for vegans. Although vegans and vegetarians have lower intakes of long-chain omega-3 fats than people who eat fish, there is no strong evidence that vegans or vegetarians have poorer health as a result.

How much fat should we eat, and how much fat are we currently eating in the UK?

The government recommends that total fat intake should not exceed 35% of our total daily calories. On average in the UK we are achieving this. Our saturated fat intake should not exceed 11% of total energy intake from food, which is roughly 30g per day for men and 20g per day for women.

Health concerns around fats

Does fat in the diet make you put on weight?

Foods that are high in fat are also ‘energy dense’, that is, they have a high number of calories per gram. High-fat foods can also be very palatable (that is, they taste good!) and both these factors can make it easy to eat a lot of calories from these foods. If we eat more calories than we need then, over time, this will lead to weight gain.

Table 2. UK dietary fat recommendations and intakes in the UK.

However, weight gain can be a result of excess calories from any source in the diet. Some dietary patterns that are relatively high in fat such as the Mediterranean diet are associated with health benefits – in this case the fat in the diet is mainly unsaturated and coming from foods such as nuts, oily fish and olive oil. The most important thing is to have a healthy dietary pattern overall with most of the fat in the diet coming from unsaturated sources.

Low-fat weight loss diets have been used for many years and can be effective for some people. Studies comparing different weight loss diets in the longer term (6-12 months) have found that there is no one diet that is the ‘best’ for weight loss, and this is down to different things working for different people. If you do want to reduce the amount of fat in your diet overall then you can do so by limiting high-fat foods such as deep-fried chips, pastries, cakes and biscuits, reducing the fat you use when cooking and by choosing reduced fat products such as low-fat yogurt or fat spread.

I've read that saturated fat isn't bad for my heart anymore - is it true?

Some headlines in recent years have suggested that saturated fat may not be strongly associated with heart disease, but it is important to remember that these headlines do not match up with current scientific understanding based on looking at all the evidence.

Since the 1980s, dietary guidelines in the UK have recommended limiting saturated fat because studies have shown that the kind of saturated fats we typically eat in our diet increase LDL-cholesterol levels, which can increase the risk of heart disease.  

But what we replace saturated fat with in our diet is important – good evidence shows that replacing saturated fat with unsaturated fats in the diet reduces blood cholesterol and lowers the risk of heart disease and stroke. We also need to remember that saturated fat is just one part of our overall diet, and we need to pay attention to what foods we include in the overall diet, for example wholegrains and fruit and vegetables and other high fibre foods, since consuming high amounts of these foods is associated with reduced risk of heart disease.

Risk of heart disease is also dependent on other factors like smoking, alcohol intake, weight status and physical activity levels. Therefore, overall diet and lifestyle, not just the amount of saturated fat we consume, is important.

Making better choices with the fats in our diets

There are some ways that we can reduce our intake of saturated fats and replace with small amounts of unsaturated fats as part of a healthy, balanced diet.

Eat foods high in saturated fat less often (and in smaller amounts)

The UK Eatwell Guide encourages us to replace saturated fat with unsaturated fat as part of a healthy, balanced diet. Foods high in fat and saturated fat such as pastries, biscuits, cakes, ice cream and chocolate are placed in a group outside of the main food groups, along with foods high in salt and/or sugars. These foods tend to be high in calories, if they are included in the diet they should only be eaten less often and in smaller amounts.

Make some simple swaps

Make some small changes to the foods and drinks you include in your diet to save on saturated fat.

Take a look at the Choose your fats wisely guide below for more tips on choosing the best oils for cooking and flavouring your food.

How can I tell if a food is high in fat or saturated fat?

Food labels on the front of packs can be a useful tool to help us identify whether foods are high (red), medium (amber) or low (green) in fat, saturated fat, sugars and salt (see example shown right). It’s a good idea to choose foods with mostly ambers or greens most of the time, in the context of a healthy, balanced diet. Some foods such as oily fish or nuts that are naturally high in fat may be labelled as ‘red’ for fat or saturated fat, but these are still healthy foods to include in the diet.

The label may also show the percentage (%) that a portion of the food or drink contributes to your daily Reference Intake (RI). This is the maximum amount that adults should have each day (see below) and is not intended as a target that needs to be met.

Figures based on typical adult female

Food packaging can also show claims such as ‘low fat’, ‘fat free’, ‘low in saturated fat’, ‘lower fat’ or ‘reduced fat’. Remember that foods that are lower in fat or reduced fat are not necessarily low in fat overall. For example, if the type of food is generally high in fat (such as mayonnaise), the lower or reduced fat version may still be a high-fat food, for example reduced fat mayonnaise contains less fat than standard mayonnaise but still has a red traffic light for total fat.

For more information on food labels read our pages on food labelling.

Answers to common questions on fats and oils and health

Is coconut oil good for me?

Coconut oil has become popular as a cooking ingredient, but it is very high in saturated fat – it actually contains more than butter! Therefore, coconut oil should be consumed less often and in small amounts. 

Learn more about coconut oil in our answers to some common questions about coconut oil.

What about cholesterol in foods?

In the past, it was thought that eating foods containing cholesterol (for example eggs, liver, kidney and shellfish such as prawns and crab) would raise our blood cholesterol. However, the amount of saturated fat in the diet has much more of an impact on blood cholesterol levels than cholesterol in foods. So, there is no need to avoid or minimise these foods with respect to your cholesterol unless you have been advised otherwise by a health professional.

Are dairy foods bad for my heart?

Although most of the fat in dairy foods is saturated fat, more evidence is emerging that dairy foods may actually reduce the risk of heart disease. This may be because saturated fat in full-fat dairy foods such as whole milk and whole yogurt are less harmful to health than that present in other foods (such as butter, coconut oil and palm oil) due to the unique chemical structure and other nutrients present within milk, cheese and yogurt, collectively known as the ‘food matrix.’ Dairy foods can form an important part of a healthy, balanced diet, as they are important providers of protein, calcium and other minerals such as iodine. However, it is still recommended that we choose lower fat versions of dairy foods most of the time, such as semi-skimmed, skimmed or 1% fat milk, reduced or lower fat cheeses (cottage cheese or quark) and lower fat yogurts as these provide the important nutrients with fewer calories. Because many UK adults are overweight or obese, lower fat dairy can be important for weight control.

I've heard oily fish is good for me, but I don't eat it - should I take fish oil supplements?

A review of the health benefits of taking fish oil or omega-3 supplements found that they did not have an effect, although there was some evidence of a slight reduction in coronary events or death (those caused by illness of the arteries that supply the heart) and that DHA and EPA may reduce triglycerides (a type of fat) in the blood.

Oily fish (such as salmon, mackerel and trout) is the best source of the long-chain omega-3 fats EPA and DHA, which are associated with heart health benefits, because it also provides important nutrients such as protein and minerals. It is recommended that we aim to consume at least two portions of fish per week, one of which should be an oily fish. If you do not like or do not eat oily fish, you can get omega-3 fats from other plant foods (see above). However, these are shorter chain omega-3 fats, such as ALA, and only a small amount can be converted in the body into the long-chain omega-3 forms - the type that is thought to be most beneficial for health. Although vegans and vegetarians have lower intakes of long-chain omega-3 fats than people who eat fish, there is no strong evidence that they have poorer health as a result.

If you do choose to take a supplement, go for a fish oil or an omega-3 oil (rather than fish or cod liver oil) that provides about 450mg EPA and DHA per daily dose. Take care with vitamin A – if your omega-3 oil supplement contains vitamin A you should not have more than a total of 1.5mg (1500mcg) of vitamin A per day from both food and supplements together. If you are pregnant, trying for a baby or breastfeeding, avoid any supplements containing vitamin A (also called retinol). You can also get supplements suitable for vegans containing long-chain omega-3s from microalgae.

Last reviewed June 2021. Next review due June 2024.