Following are a number of back-translations as well as a sample translation for translators of Proverbs 14:30:

• Kupsabiny: “If a person has peace, (he) is happy/rejoices,
  but the one with a black stomach (envious), suffers.” (Source: Kupsabiny Back Translation)
• Newari: “If one’s heart is satisfied,
  one will have good health,
  if one gets envious, his bones will rot.” (Source: Newari Back Translation)
• Hiligaynon: “A peaceful mind can-make-healthy body, but envy is like a disease that nibbles/rots the bones.” (Source: Hiligaynon Back Translation)
• Kankanaey: “The body is healthy if/when the mind is content, but envy, it is like a sickness of the bones that uses-up strength.” (Source: Kankanaey Back Translation)
• English: “Having a mind that is peaceful results in having a healthy body;
  having a mind that is often in turmoil is like cancer in a person’s bones.” (Source: Translation for Translators)