Even though lipids and carbohydrates are made from the same elements (carbon, hydrogen, and oxygen), why is it easy to tell them apart when viewing a model of each?

Lipids contain more energy that carbohydrates because they contain more carbon to hydrogen bonds to release energy when broken.
A macromolecule is a large molecule. There are four groups of macromolecules: carbohydrates, proteins, nucleic acids and lipids. Lipids consist of glycerol and fatty acids and are constructed from fats, oils, waxes, phospholipids and steroids. A lipid's function is to insulate the body and provide warmth in cold conditions. It can be concluded that a person with very little body fat gets very cold easily and a person with a lot of body fat gets very warm very quickly.