Derived fats - combine simple and compound fats. A sterol is an example of a derived fat. The primary function of protein is to build and repair tissue. They are the most abundant substances in the human body. They are the major component in nearly every cell of the body.
Proteins are key components in enzymes, antibodies, and hormones.
Proteins supply energy for work when carbohydrates and fats are not available. Proteins are made up of individual amino acid units. The number of amino acids in a protein varies from very few to hundreds. Essential amino acids are those that cannot be produced by the human body. They are obtained only through the diet.