In nutrition, diet is the sum of food consumed by a person or other organism. Dietary habits are the habitual decisions an individual or culture makes when choosing what foods to eat.

Dietary habits and choices play a significant role in health and mortality, and can also define cultures and play a role in religion. Nutrition is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet. 

A poor diet can have an injurious impact on health.