The chemical name for a fat is a triglyceride. A triglyceride molecule is made up of three fatty acids parts attached to one glycerol part. The fatty acids are the most important part of the molecule. They can either be saturated (full up) or unsaturated (not full up) with hydrogen atoms.
Saturated fats have single bonds between all of the carbon atoms in the carbon chain. All of the bonds are saturated with hydrogen. Saturated fats are solid at room temperature and generally found in animal products, such as meat, butter, ghee, cream, hard cheese and eggs. Saturated fats have been linked to heart disease. Foods that are high in saturated fat will contain cholesterol.
The average man should eat no more than 30g of saturated fat a day.
The average woman should eat no more than 20g of saturated fat a day.
Unsaturated fats: Sometimes the chain of carbon atoms has some hydrogen atoms missing. This creates an unsaturated molecule and results in a ‘double bond’ between two of the carbon atoms in the chain. The double bond puts a bend or curve in the carbon chain and this allows movement. Unsaturated fats are liquids at room temperature, for example, sunflower or olive oil.
Eating unsaturated fats instead of saturated is recommended. Unsaturated fats are found in:
- Oily fish such as salmon, sardines and mackerel
- Nuts and seeds
- Sunflower and olive oils.
They may lower blood cholesterol levels and reduce the risk of heart disease. There are two types of unsaturated fats:
- Monounsaturated fatty acids have one double bond. The prefix ‘mono’ means one. Avocados, cashews and peanuts are good sources of monounsaturated fatty acids.
- Polyunsaturated fatty acids have two or more double bonds in the carbon chains. The prefix ‘poly’ means two or more. Corn, soya and sunflower oils are good sources of polyunsaturated fatty acids.
Essential fatty acids: Omega 3 and omega 6 are two polyunsaturated fatty acids that are very important for health. They are called essential fatty acids. They must be eaten in the diet as the body cannot make them. They are vital for the proper functioning of the brain and heart and for the development of our nervous system.
- Omega 3 is found in oily fish, seeds and green leafy vegetables.
- Omega 6 is found in vegetables, grains, seeds and chicken.