expression
an army marches on its stomach; you can't fight on an empty stomach
Proverb meaning that one cannot accomplish anything without first satisfying basic needs like hunger. Often used to emphasize the importance of eating before undertaking a difficult task.
腹が減っては戦は出来ぬというから、まずは昼食にしよう。
They say an army marches on its stomach, so let's have lunch first.
試験の前にはしっかり食べなさい。腹が減っては戦は出来ぬよ。
Eat well before the exam. You can't fight on an empty stomach.
A Japanese proverb of uncertain origin, possibly derived from a similar Chinese saying or from samurai-era wisdom. The literal meaning is 'with an empty stomach, one cannot wage war'.