Simple carbohydrates are called simple sugars. Sugars are found in a variety of natural food sources including fruit, vegetables and milk, and give food a sweet taste. But they also raise blood glucose levels quickly.
Sugars can be categorised as single sugars (monosaccharides), which include glucose, fructose and galactose, or double sugars (disaccharides), which include sucrose (table sugar), lactose and maltose.
Complex carbohydrates, also known as polysaccharides, are starches formed by longer saccharide chains, which means they take longer to break down.
Chemically, they usually comprise of three or more linked sugars.
Strictly speaking, the term complex carbohydrate refers to any starches, including the highly refined starches found in:
White bread
Cakes
Most pastries and
Many other food sources
When dietitians and nutritionists advise having complex carbohydrates, however, they are usually referring to whole grain foods and starchy vegetables which are more slowly absorbed than refined carbohydrate.
