Health, as defined by the World Health Organization (WHO), is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has been subject to controversy, as it may have limited value for implementation. Health may be defined as the ability to adapt and manage physical, mental and social challenges throughout life.
When a clearer distinction is intended, healthy is used to describe the state of the object, and healthful describes its ability to impart health to the recipient. Vegetables in good condition are both healthy (i.e., not rotten or diseased) and healthful (i.e., they improve the eaters' health, compared to eating junk food). By contrast, a poisonous plant can be healthy, but it is not healthful to eat it.