There are several substances that are needed in large quantities in the human body. They are: Carbohydrates, Lipids, Proteins, and Nucleic Acids

Lipids: Lipids have many functions in the human body. They are used for long term energy storage, insulation, and protection. They also help dissolve vitamins for digestion. Lipids can be obtained from oils, such as vegetable oil, or fats. There are two types fats; saturated and unsaturated. In unsaturated fats, some of the atoms form double bonds which causes a kink in the chain. Because of this, unsaturated fats are less dense and are liquid at room temperature

Proteins: Proteins are made up of amino acids. The amino acids are put together into polypeptide chains and they order in which the amino acids occur is called the primary structure of the protein. The polypeptide chains are coiled and folded in various ways. a fold or helix in a polypeptide is called the secondary structure of a protein. The mixture of helices and folded pleats found in a certain protein (and it differs from protein to protein) is called the tertiary structure. finally, the way that multiple tertiary structures stick together is called the quaternary structure, however, this is not present in all proteins.

Nucleic Acids: covalently bonded molecules with Carbon, Hydrogen, Oxygen, Nitrogen, and Sulfur. Their function is to store info and direct activity in the cell. Their structure determines function and their subunit is nucleotides.