an apple a day keeps the doctor away

saying2

1. •
   Apples are healthy and stave off illnesses.

   • Of course I eat an apple every evening—an apple a day keeps the doctor away—but still, you ought to have more prunes, and not all these fancy doodads. — 1922
2. •
   Healthy eating prevents illness.

   • He advocated the increased use of fruit, for he believed in the old saying, "An apple a day keeps the doctor away." — 1887