Fats are a rich source of energy. They supply a larger amount of energy per gram than carbohydrates and proteins thereby providing an efficient energy storage system. One gram of any type of fat gives 37kJ or 9kcal.
Fats are made up of fatty acids which are known as saturated, monounsaturated or polyunsaturated depending on their chemical structure.
Whilst some fats can be harmful especially if there is an excessive intake, other fats are essential and beneficial to the body.
Fats have an amazing effect on the human body; they play three major roles
- Cell membrane structure
- Provision of energy and
- The control of energy
The digestion and metabolism of certain nutrients are improved by fats as is the absorption and transport of others such as fat soluble vitamins.
Good types of fats have protective abilities for organs; the brain alone needs a variety of different fats. Fats also provide insulation for the body.
Fats in the diet
All fats contain a mixture of saturated and unsaturated fats. A food that contains a lot of fat is called energy-dense. These foods will provide a lot of energy but consuming too many of these foods may give an excessive energy intake. This excessive energy may be stored as body fat which could lead to weight gain.
It is considered that no more than 20% of the calorie intake should come from fats and that no more than one third of that percentage should come from saturated fats. Saturated fat should be as low as possible as it can encourage raised LDL (bad) cholesterol. The other third of the percentage intake should be from polyunsaturated fats that provide essential fatty acids (EFAs).
Choosing foods containing unsaturated, monounsaturated and polyunsaturated fats and less saturated fat is preferable. Monounsaturated and polyunsaturated fats are found in oils such as olive, rapeseed and also avocados, nuts and seeds.
Essential Fatty Acids
Although some of the fatty acids required can be made in the body, there are two that need to be included via the diet and they are known as essential fatty acids (EFAs), meaning they are essential for life. These are linoleic (or omega-6) fatty acid and alpha-linoleic (or omega-3) fatty acid.
The body uses these EFAs to help regulate all aspects of its activity, without these our cells would run out of the building blocks they need to maintain health.
Omega-3 and omega-6 can only be obtained from food sources. They can both be found widely distributed in plant oils and omega-3 can also be found in high concentrations within fish oils.
Good sources of Omega 3 are oily fish such as salmon, mackerel, herring, fresh tuna, and sardines, plant sources such as flax seeds (ground or crushed to release the oils) and flax oil, hemp seeds and hemp oil.
Omega 6 can be found in all nuts, pumpkin seeds, sesame seeds, sunflower seeds and vegetable oils such as sunflower oil, corn and sesame.
Essential fats can help aid in weight loss as they are important for softening the cell membrane that encourages accumulated fat in the cell to be removed. Without these essential fats the cell membrane hardens and the fat is more difficult to eliminate, potentially contributing to weight gain.
Essential fats are also important in helping to prevent a loss of moisture at a cellular level for example from the skin.
Essential fats elevate mood, they are also vital for foetal development during pregnancy and when breastfeeding.