Malnutrition is a general term for the medical condition caused by an improper or insufficient diet.
It most often refers to undernutrition resulting from inadequate consumption, poor absorption, or excessive loss of nutrients, but the term can also encompass overnutrition, resulting from overeating or excessive intake of specific nutrients.
An individual will experience malnutrition if the appropriate amount, kind or quality of nutrients comprising a healthy diet are not consumed for an extended period of time.
An extended period of malnutrition can result in starvation.
Malnutrition as the lack of sufficient nutrients to maintain healthy bodily functions is typically associated with extreme poverty in economically developing countries, while malnutrition as the result of inappropriate dieting, overeating or the absence of a "balanced diet" is often observed in economically developed countries (eg. as indicated by increasing levels of obesity).