an apple a day keeps the doctor away

An apple a day keeps the doctor away is a literal way of showing the importance of healthy eating. Apples are known to promote health and are often the first fruit thought of when speaking of a healthy diet which is why this cliche has apple and not a different type of fruit. Apples contain plenty of Vitamin C which helps the immune system, reduce tooth decay and reduce cholesterol; all of which will keep someone from frequent doctor visits.