Healthy describes something that has good health, while healthful describes something that gives good health. A person is healthy; a diet is healthful because it makes you healthy. In everyday use, though, healthy has taken over both jobs, so healthy diet is now far more common than healthful diet.
The core difference
Healthy means possessing good health; healthful means producing good health in others.
- healthy — in good physical or mental condition: the doctor confirmed the baby was healthy.
- healthful — beneficial to bodily health: oily fish is a healthful addition to most diets.
- healthy — also used for a sizeable amount: the company reported a healthy profit.
How to tell them apart
A simple test: ask who or what has the good health. If it is the subject itself that is well, reach for healthy, as in a healthy child or a healthy heart. If the subject is instead the cause of someone else's good health, healthful is the more precise choice, as in a healthful breakfast or a healthful habit.
In practice, healthy is used for both jobs so often that healthy diet and healthy lifestyle are now standard, and healthful can read as slightly formal or old-fashioned. It is still worth knowing the distinction for careful writing, even if strict enforcement is no longer expected.
