In nutrition, diet is the sum of food that is eaten by a person or another organism. Dietary habits are the usual decisions someone or a culture makes when choosing what foods to eat. With the word diet, it is often expressed the use of specific intake of nutrition for health or weight-management reasons (with the two often being related). Although humans are omnivores, each culture and each person holds some food preferences or some food taboos, due to personal tastes or ethical reasons. Individual dietary choices may be more or less healthful. A proper nutrition requires a proper ingestion and, also important, the absorption of vitamins, minerals, and food energy in the form of carbohydrates, proteins, and fats. Dietary habits and choices play a significant role in health and mortality, and can also define cultures and play a role in religion.