Abstract: Disclosed is a concrete composition that comprises water, a cementitious material, and an aggregate material, the aggregate material comprising a granular starch. In accordance with preferred embodiments of the invention, the granular starch is a washed, pre-swollen starch, and is added to the composition in an amount ranging from about 1% to about 20% by weight of the cementitious material. The starch granules are swollen in the uncured composition but liberate water and shrink to their unswollen size as the concrete cures, thus providing a cured lightweight concrete. Also disclosed is a method for preparing a concrete composition. The disclosed method comprises providing starch granules, mixing the starch granules with water and a cementitious material to form an uncured concrete composition, and subsequently curing the uncured concrete composition thus formed.