Fats and oils (lipids) have the same basic chemical structure, but there physical appearance differs at normal room temperature:
- Fats are solid at room temperature
- Oils are liquid at room temperature.
Fats and oils are high energy foods.They are used for energy and warmth.
Fats and oils are formed by glycerol and fatty acids combining to form fat molecules. There are at least forty different types of fatty acid. They may be either saturated or unsaturated.
Saturated fatty acids
These are predominantly present in fats which are solid at room temperature, for example, milk, butter, animal fats, dairy foods, coconut oil
Unsaturated fatty acids
Two categories
Monounsaturated fatty acids eg oleic acid found in most animal and plant fats and oils especially Olive Oil.
Polyunsaturated fatty acids eg linoleic acid, linolenic acid found mainly in vegetable oils.
Unsaturated fatty acids occur mainly in oils.
Most fats and oils contain a mixture of saturated and unsaturated fatty acids but in widely varying proportions.
An intake of fat in the diet is essential as some fatty acids are required for important functions in the body. Fat soluble vitamins A, D, E and K must also be provided by food containing fat.
A fat free diet is not only difficult to prepare but is also very unpalatable.