What is a carbohydrate?

A carbohydrate is a long molecule made up of lots of individual units called monosaccharides. These units are sugars, including glucose, fructose and lactose.

When two of these units are bound together, it's called a disaccharide. When more than one are bound together in a chain, it is a polysaccharide - this is what starch is. Starch is a major component of a healthy diet, and is found in potatoes, bread, pasta and more.