Fat: the facts

Too much fat in your diet, especially saturated fats, can raise your cholesterol, which increases the risk of heart disease.  

Current UK government guidelines advise cutting down on all fats and replacing saturated fat with some unsaturated fat.

Why we need some fat

A small amount of fat is an essential part of a healthy, balanced diet. Fat is a source of essential fatty acids, which the body cannot make itself.

Fat helps the body absorb vitamin A, vitamin D and vitamin E. These vitamins are fat-soluble, meaning they can only be absorbed with the help of fats.

Any fat not used by your body's cells or to create energy is converted into body fat. Likewise, unused carbohydrate and protein are also converted into body fat.

All types of fat are high in energy. A gram of fat, whether saturated or unsaturated, provides 9kcal (37kJ) of energy compared with 4kcal (17kJ) for carbohydrate and protein.

The main types of fat found in food are:

• saturated fats 
• unsaturated fats

Most fats and oils contain both saturated and unsaturated fats in different proportions.

As part of a healthy diet, we should try to cut down on foods and drinks high in saturated fats and trans fats, and replace some of them with unsaturated fats.

Saturated fats

Saturated fats are found in many foods, both sweet and savoury.

Most of them come from animal sources, including meat and dairy products, as well as some plant foods, like palm oil and coconut oil.

Foods high in saturated fats

• fatty cuts of meat
• meat products, including sausages and pies
• butter, ghee and lard
• cheese, especially hard cheese like cheddar
• cream, soured cream and ice cream
• some savoury snacks, like cheese crackers and some popcorns
• chocolate confectionery
• biscuits, cakes and pastries
• palm oil
• coconut oil and coconut cream

Cholesterol and sat fats

Cholesterol is mostly made by the body in the liver.

It's carried in the blood as:

• low-density lipoprotein (LDL)
• high-density lipoprotein (HDL)

Too much saturated fats in your diet can raise LDL cholesterol in the blood, which can increase the risk of heart disease and stroke.

HDL cholesterol has a positive effect by taking cholesterol from parts of the body where there's too much of it to the liver, where it's disposed of.

Saturated fat guidelines

Most people in the UK eat too much saturated fats.

The government recommends that:

• men should not have more than 30g of saturated fat a day
• women should not have more than 20g of saturated fat a day
• children should have less

Trans fats

Trans fats are found naturally at low levels in some foods, such as meat and dairy products.

Trans fats can also be found in partially hydrogenated vegetable oil. Hydrogenated vegetable oil must be declared on a food's ingredients list if present.

Like saturated fats, trans fats can raise cholesterol levels in the blood.

The government recommends that:

• adults should not have more than about 5g of trans fats a day

But most people in the UK do not eat a lot of trans fats. On average, we eat about half the recommended maximum.

Most of the supermarkets in the UK have removed partially hydrogenated vegetable oil from all their own-brand products.

We eat a lot more saturated fats than trans fats. This means that when looking at the amount of fat in your diet, it's more important to focus on reducing the amount of saturated fats.

Unsaturated fats

If you want to cut your risk of heart disease, it's best to reduce your overall fat intake and swap saturated fats for unsaturated fats.

There's good evidence that replacing saturated fats with some unsaturated fats can help lower cholesterol.

Found primarily in oils from plants and fish, unsaturated fats can be either polyunsaturated or monounsaturated.

Monounsaturated fats

Monounsaturated fats help protect our hearts by maintaining levels of good HDL cholesterol while reducing levels of bad LDL cholesterol.

Monounsaturated fats are found in:

• olive oil, rapeseed oil and their spreads
• avocados
• some nuts, such as almonds, brazils and peanuts

Polyunsaturated fats can help lower the level of LDL cholesterol. 

There are 2 main types of polyunsaturated fats: omega-3 and omega-6.

Some types of omega-3 and omega-6 fats cannot be made by the body and are therefore essential in small amounts in the diet.

Omega-6 fats are found in vegetable oils, such as:

• rapeseed
• corn
• sunflower 
• some nuts

Omega-3 fats are found in oily fish, such as:

• kippers
• herring
• trout
• sardines
• salmon 
• mackerel

Most of us get enough omega-6 in our diet, but we're advised to have more omega-3 by eating at least 2 portions of fish a week, including 1 portion of oily fish.

Vegetable sources of omega-3 fats are not thought to have the same benefits on heart health as those found in fish.

Buying lower fat foods

The nutrition labels on food packaging can help you cut down on total fat and saturated fat (also listed as "saturates", or "sat fat").

Nutrition information can be presented in different ways on the front and back of packs.

Total fat

• high fat – more than 17.5g of fat per 100g
• low fat – 3g of fat or less per 100g, or 1.5g of fat per 100ml for liquids (1.8g of fat per 100ml for semi-skimmed milk)
• fat-free – 0.5g of fat or less per 100g or 100ml

Saturated fat

• high in sat fat – more than 5g of saturates per 100g
• low in sat fat – 1.5g of saturates or less per 100g or 0.75g per 100ml for liquids
• sat fat-free – 0.1g of saturates per 100g or 100ml

'Lower fat' labels

For a product to be labelled lower fat, reduced fat, lite or light, it has to contain at least 30% less fat than a similar product.

But if the type of food in question is high in fat in the first place, the lower fat version may also still be high in fat (17.5g or more of fat per 100g).

For example, a lower fat mayonnaise is 30% lower in fat than the standard version, but is still high in fat.

These foods also are not necessarily low in calories. Sometimes the fat is replaced with sugar and may end up with a similar energy content.

To be sure of the fat content and the energy content, remember to check the nutrition label on the packet.

Cutting down on fat is only 1 aspect of achieving a healthy diet.

Find out more about how to get a balanced nutritious diet in the Eatwell Guide.

Use the Be Food Smart app to compare products and get ideas on how to make healthy choices.

Page last reviewed: Mon May 2017 Next review due: Fri May 2020