Lipids are macromolecules which means they are large organic molecules. Other macromolecules include proteins, carbohydrates and nucleic acids. Lipids are also polymers meaning they are made up of many smaller units called monomers. Lipids are non-polar molecules meaning they do not dissolve easily in water because water is a polar substance. Lipids are made up of the elements carbon, hydrogen and oxygen. Lipids are found as energy storage in humans, they make up the membrane of our cell and are found in many of the foods we eat.