It's not the starving man that would have the loaf of bread to sell. It would be a farmer or a baker. The starving man is the one with no resources to obtain the bread. The Baker would use the gold coin to obtain flour from a farmer and wood or other fuel for his ovens. He'd also want clothing and shoes for his family.
My ancesters, parents, grandparents and some great grandparents, did not starve during the depression. They were farmers. They sold to whover had money, but they ate what they needed first, then sold the surplus.
My paternal grandmother was (effectively) a single Mom with 3 very close together children. But her parents, and siblings were farmers. Her family didn't starve either, but they did work on the family's farms, and she worked in other peoples houses, cooking cleaning and doing whatever they did not want to, or could not, do for themselves.
Silver would be better than gold in that circumstance. Those that are pushing gold are not talking about the great depression, though, they are talking about a “collapse” where fiat money is worthless.
Your grandparents used paper (fiat) money to survive the depression.