Mainly there are 2 big reasons why we need saturated fats:
60% of our brain is made of fat. 30% of our brain is made of saturated fats.
Our cells are made of protein and its membranes are made by fat. 45% of the cell membrane is made up of saturated fats. The cell membrane have the function of protecting the cell. A well constituted membrane is a good protection for our cells.
Saturated fats are precursors for hormones like testosterone or cortisol for example.
Types of saturated fats:
Caprylic acid: Found in breast milk, coconut oil and dairy. Antiviral and supports immune system.
Lauric acid: Found in breast milk and coconut oil. Antiviral and supports immune system.
Palmitic acid: Found in fish, nuts and seeds. 50% of our cells membrane are made by this acid.
Butyric acid: Found in butter, feeds the cells in the colon.