ABSTRACT
This chapter focuses on food: the way it is produced in different ecosystems, the way it is prepared in different cultures, and the way it is distributed in different economies. People need energy for maintenance and growth, as well as for the internal and external work their bodies do. Carbohydrates, fats, and proteins are sources of energy, which is measured in kilocalories. The combinations of foods that are eaten affect the absorption of nutrients from these foods; in other words, the bioavailability of nutrients is influenced by the whole mixture of foods in the diet. Nutritional requirements are complex. We are constantly learning more about the effects of excesses and deficiencies of particular nutrients. Specific deficiency diseases tend to have a distribution that reflects the ecology of food plants unless people are protected from deficiency through a cultural or biological adaptation. Pellagra is characterized by a distinctive rash, diarrhea, and mental disturbance.
