Carbohydrates are energy-producing substances typical of plant-based foods. Absorbable carbohydrates are calculated as the sum of sugars and starch. From absorbable carbohydrates, the body gets glucose, or blood sugar, which produces 17 kJ/g (4 kcal) of energy in the body. Absorbable carbohydrates include sugars and starch. Sugars include mono- and disaccharides like sucrose, glucose, fructose, lactose, and maltose.