Erdkamp estimated that the amount needed would be at least 150,000 tonnes, calculating that each resident of the city consumed 200 kilograms (440 lb) of grain per year. Rickman estimated that Rome needed 40 million modii (200,000 tonnes) of grain per year to feed its population. Several scholars have attempted to compute the total amount of grain need to supply the city of Rome. Grain made into bread was, by far, the most important element in the Roman diet.
