A man cannot live by the air.

Air may be essential, but it cannot sustain a person by itself. Food and other basic provisions are also needed to stay alive.

The proverb makes a practical point: people cannot be expected to keep going if their essential needs are left unmet.

Use this proverb to challenge an expectation that someone can manage without food or other necessary provisions. It emphasizes practical needs rather than a lack of willingness or effort.