en_tn/isa/09/20.md

They will grab food on the right hand ... on the left hand

This expression means that the people will grab food wherever they can find it. (See: rc://en/ta/man/translate/figs-metonymy)

Each will even eat the flesh of his own arm

Possible meanings are 1) people will be so hungry that they will want to eat or will actually eat their own arms or 2) the word "arm" is a metaphor for the person's neighbor. (See: rc://en/ta/man/translate/figs-metaphor)