Now, what are carbohydrates? Is sugar a carbohydrate? Yep. What about starch? Well, starch is also part of the carbohydrates. Fibre? Fibre is also part of the carbohydrates, but a special kind as we’ll see. We’ll start by looking at the chemistry of carbohydrates. So carbohydrates are built from small building blocks called monosaccharides. And the main monosaccharide is glucose.