What were the foods and drinks that the Prophet (peace and blessings be upon him) and his companions considered to be legally obligatory to consume, such that one who abstained from them would be punished, given their necessity for a person and the threat their abandonment posed to one's life?

There is no religious text that obliges an individual to consume a specific food or drink. However, there are texts that command the preservation of health and avoiding what leads to destruction, such as eating and drinking without extravagance. In His (the Almighty's) saying: "And eat and drink, but be not excessive. Indeed, He likes not those who commit excess" (Al-A'raf: 31), there is guidance for preserving health.

The jurists have stipulated the obligation to consume food for anyone who fears destruction by abstaining from it, and they are sinful if they refuse and die, because eating and drinking to the extent that averts destruction is an obligation. So, whoever abandons them until they perish has committed suicide, by casting themselves into the forbidden destruction. Likewise, if a person is forced to consume something forbidden to avert destruction, it becomes obligatory for them to eat or drink. If they refuse until they die, they would be a killer of their own soul.