FOOD
What is food? Looked at in biological terms, it would appear that food is merely a source of the energy and nutrients essential for life. However, viewed from an anthropological perspective, it becomes evident that food has played a central role in human history. While the everyday quest for food shaped the life of prehistoric man, the onset of the production of a reliable and sufficient supply of food is likely to have led to the rise of civilizations, and to human population expansion. Furthermore, the ability of man to colonize almost every part of the world is at least in part due to his adaptability with regard to food. Not only are humans omnivorous, they have also shown remarkable ingenuity in identifying and preparing nutritious foods out of unpromising materials. For example, bitter cassava (Manihot esculenta), a root crop that contains toxic levels of cyanide-producing compounds, comprises, after thorough processing, the major food item in the diet of millions of people worldwide.
Beyond merely nourishing the body, what we eat and with whom we eat can inspire and strengthen the bonds between individuals, communities, and even countries.Food is a Material, usually of plant or animal origin, that contains or consists of essential body nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals, and is ingested and assimilated by an organism to produce energy, stimulate growth, and maintain life.
Any substance taken into the body for the purpose of providing nourishment. However, factors such as satisfying social needs, achieving psychological ends, and satisfying hunger, more than nutritional needs, govern the selection and consumption of foods. When foods are selected carefully, they can provide all of the essential nutrients needed for normal functioning of the human body. In this context, food is necessary to provide energy, to provide structural components for building and repairing body tissues, and to regulate body processes. See also Metabolism; Nutrition.
There are essential nutrients (carbohydrates, fats, proteins, minerals, vitamins, and water) that have specific functions in the human body. When the energy-yielding nutrients, that is, carbohydrates, fats, and proteins, are oxidized in the body, energy is captured in a chemical compound known as adenosine triphosphate (ATP), which will then release the energy slowly so that it can be used for physical activity (work), heat production, and metabolic processes. Enzymes, vitamins, and minerals, as well as water, are needed in order for these oxidation reactions to take place. Energy requirements are expressed in terms of kilocalories (kcal), calories (cal), or kilojoules (kJ). Fats and carbohydrates contain only the elements carbon, oxygen, and hydrogen. Since fats contain less oxygen than carbohydrates, they have greater potential for oxidation and thus provide more energy per gram than carbohydrates. Proteins also contain nitrogen, but this does not contribute substantially to the energy value. The physiological fuel value, or the amount of energy generated in the body, of 1 gram of protein is 4 kcal (17 kJ); carbohydrate, 4 kcal (17 kJ); fat, 9 kcal (38 kJ). See also Enzyme; Vitamin.
Although it is unlikely that any individual food or combination of foods can provide complete disease protection, risk of chronic disease can be reduced by increased consumption of plant-based foods and decreased consumption of fats. See also Food engineering; Food manufacturing; Food microbiology; Food science.
