Seneca · On the healing power of the mind

Letters 78.24

“Poor sick fellow!”—he will eat as much as he can digest. There will be no boar lying before his eyes, banished from the table as if it were a common meat; and on his sideboard there will be heaped together no breast-meat of birds, because it sickens him to see birds served whole. But what evil has been done to you? You will dine like a sick man, nay, sometimes like a sound man.

Seneca, Letters to Lucilius 78.24, translated by Richard Mott Gummere