Fat in food plays an important role in supplying energy to the body as well as other nutrients such as the fat soluble vitamins. It is the most energy dense nutrient containing twice as much energy per gram as carbohydrate and protein.
Sometimes the high fat content of food is obvious such as the fat in meat, at other times it is not, for example, fat hidden in cakes and biscuits.
Understanding how much and what type of fat to include in your diet is key to maintaining a healthy weight and keeping blood cholesterol and lipid levels balanced.
What is fat?
Fats and oils are made up of chains of fatty acids which can either be saturated or unsaturated. Fats and oils are found in animal and plant based foods.
What is the difference between a fat and an oil?
Oils are fats that are liquid at room temperature, like the vegetable oils used in cooking. Oils contain more unsaturated fats. Fats are solid at room temperature, like butter and contain more saturated fats.
Do we need fat in our diet?
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, which means they can only be absorbed with the help of fats.
Any fat that's not used by your body's cells or turned into energy is converted into body fat.
All types of fat are high in energy. A gram of fat, whether it's saturated or unsaturated, provides 9kcal (37kJ) of energy compared with 4kcal (17kJ) for carbohydrate and protein.
Fat also plays an important role in making food taste good.
What are the main types of fat in the diet?
The main types of fat found in food are:
Most fats in our diet contain a mix of saturated and unsaturated fatty acids in different proportions.
Unsaturated fats
Most foods high in unsaturated fats come from plant foods and fish
Oily fish contain a special type of unsaturated fat called omega-3 fatty acids. Eating oily fish is associated with health benefits including protecting against heart disease, contributing to good bone health and reducing symptoms of inflammatory disease such as rheumatoid arthritis.
Saturated fats
Most foods high in saturated fats come from animal sources, including meat and dairy products, as well as some plant foods, such as palm oil and coconut oil.
Foods high in saturated fats
Eating a diet high in saturated fats increases blood cholesterol levels, which are linked to the risk of developing heart disease.
Fat and heart disease
If you want to reduce your risk of heart disease, it's best to reduce your overall fat intake and swap saturated fats for unsaturated fats which can help to lower your cholesterol levels.
Fat and obesity
Foods that are high in fat provide a lot of energy and may be less filling than other foods.
This means it is easier to consume too many calories when eating a high fat diet. Many processed foods contain both fat and sugar and can lead to over consumption of calories.
Guidelines on fat intake
UK guidelines for the recommended daily, adult intake of:
Aim to eat two portions of fish each week including one portion of oily fish to obtain the omega-3 fatty acids needed for good health.
How can I tell if a food is high in fat?
Look at the amount of fat each in 100g or a portion of a food can give you an idea of how much it contributes to your daily intakes.
Planning your diet
Further reading: British Nutrition Foundation and NHS Eat Well Guide