"Food for powder" is an old idiom that was often used to describe soldiers who were seen as expendable or disposable. It referred to the fact that they were essentially being fed to the cannons as ammunition during a battle. There are many synonyms for this phrase that can be used to convey a similar idea, such as "cannon fodder," "grist for the mill," "pawns in the game," or "sacrificial lambs." These phrases all describe the idea of individuals being used and discarded by those in power, often for their own gain. They evoke a sense of helplessness and exploitation, and serve as a reminder of the darker side of conflict and war.