When meals became binding contracts

Traders who kept kosher, observed halal, or adhered to strict vegetarian diets were not simply following their religious beliefs, but also using food practices to establish networks of trust in global trade. This predates the invention of insurance and credit control systems. Food restrictions were a key component of the trust infrastructure among traders who never met in person.

Jewish traders in the Mediterranean, Muslim traders in the Indian Ocean, and Jain and Marwari traders in India all utilized food practices to build trust networks among traders who were separated by vast distances. Each trader would transfer goods or capital to someone on distant shores, with no chance of meeting them. Trust was built through dietary laws, as they were costly to fake and difficult to uphold.

For Jewish traders, observing kosher rules in a city like Cairo or Fustat demonstrated their membership in a community and adherence to their community's trade laws. Anyone could see that a Jew who transgressed these laws would damage their reputation and social standing. Historians have found that news of a cheater in Alexandria would spread to Tunis within a week, cutting the offender off from trade.

Similarly, Muslim traders in Arabia, Malabar, and East Africa had a common code of contract and partnership law enforced by mosques. A merchant in any port could observe which traders fasted and observed Halal practices, indicating their adherence to the same law. This allowed Hadhrami and Gujarati Muslim merchant families to build trading empires that persisted even after individual rulers or ports fell.

Jain and Marwari merchants in India took this practice to another level with their strict vegetarianism and avoidance of root vegetables, along with specific fasting periods. These dietary restrictions made it nearly impossible to fake over a lifetime, and since they were also endogamous trading castes, their discipline in food and marriage reinforced each other.

A Jain merchant from Rajasthan could be authenticated by any other Jain merchant in a distant trading post, acting as a substitute for a credit check that a stranger could never conduct.