What are carbohydrates?
At their most basic, carbohydrates are made of building blocks of sugars, and can be classified according to how many sugar units are combined in their molecule. Glucose, fructose and galactose are examples of single-unit sugars, also known as monosaccharides. Double-unit sugars are called disaccharides, among which sucrose (table sugar) and lactose (milk sugar) are most widely known. Monosaccharides and disaccharides are usually referred to as simple carbohydrates. Long-chain molecules, such as starches and dietary fibres, are known as complex carbohydrates. In reality, though, there are more distinct differences. Table 1 gives an overview of the major types of carbohydrates in our diet.
Carbohydrates are also known under the following names, which usually refer to specific groups of carbohydrates1:
sugars
simple and complex carbohydrates
resistant starch
dietary fibres
prebiotics
intrinsic and added sugars
The different names come from the fact that carbohydrates are classified depending on their chemical structure, but also based on their role, or source in our diet. Even leading public health authorities have no aligned common definitions for different groups of carbohydrates.
