What is the meaning of [If music be the food of love, play on]

‘If music be the food of love, play on’ is the famous opening line from Shakespeare’s comedy Twelfth Night.

The lovelorn Orsino is frustrated in his courtship of Countess Olivia. He asks for more music because he muses that an excess of music might cure his obsession with love, in the way that eating too much removes one’s appetite for food.

Music plays an important part in Shakespeare’s plays and is often used to carry the plot. It’s reasonable to surmise that he did believe music to the be ‘the food of love’.