IPA: /ˈhɛlθfəl.nəs/
KK: /ˈhɛlθfəl/
The quality of being good for your health; being beneficial to your well-being.
Eating fruits and vegetables contributes to the healthfulness of your diet.
Healthfulness → It is formed from "health" (from Old English *hælu*, meaning wholeness or well-being) and "-ful" (meaning full of) and "-ness" (meaning the state of being). The word "healthfulness" means the state of being full of health or promoting well-being.
Think of 'health' as wholeness and 'full' as being full of that wholeness — that's why healthfulness means the state of being full of health.