Types of carbohydrates. There are three main types of carbohydrates: 1  Sugar. 2  Sugar is the simplest form of carbohydrates. 3  Sugar occurs naturally in some foods, including fruits, vegetables, milk and milk products. 4  Sugars include fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose).5  Starch.ypes of carbohydrates. There are three main types of carbohydrates: 1  Sugar. 2  Sugar is the simplest form of carbohydrates. 3  Sugar occurs naturally in some foods, including fruits, vegetables, milk and milk products. 4  Sugars include fruit sugar (fructose), table sugar (sucrose) and milk sugar (lactose).