Foods and Diets Health Article

FOODS AND DIETS

Humans have evolved to depend on a continuous supply of energy (calories) and nutrients from edible plants and animals. From the dawn of civilization, humans have been omnivores. Early humans hunted or gathered whatever foods were available in the immediate environment, as determined by geography, climate, and season. The precise number of foods eaten by humans is uncertain; scientists estimate that at least twenty thousand plants have edible parts. To these must be added fungi and algae, as well as foods derived from mammals, fish, seafood, birds, eggs, milk, and exotic animals. Among food plants, about 150 have been domesticated and are cultivated on a large scale, but only about twenty constitute principal energy sources, and just three—wheat, corn, and rice—dominate world markets. What people choose to eat depends largely on culture and economics. Cultural factors explain why Asians eat rice or noodles, whereas Mediterraneans consider no meal complete without bread. There are also religious prohibitions, such as those against consuming beef, pork, or alcoholic beverages. People can choose freely from available foods only if they can afford them; without an adequate income, food choices are limited.

Foods vary in quality as well as variety. Their composition is exceedingly complex; foods contain hundreds of chemical components—including the familiar nutrients and energy sources, but also fiber, phytochemicals, and other substances that may affect health. As recently as the mid– twentieth century, most foods were produced and eaten locally. As transportation improved, production became increasingly centralized and foods were processed to permit transport and storage. Processing removed essential vitamins, minerals, and other nutritious components and added preservatives, texturizers, flavors, and colors. While highly efficient, centralized production permitted biological and other contaminants to affect larger numbers of people. Increased efficiency led to cheaper food, but it also led to other, less desirable effects of overproduction.

The food systems of industrialized countries produce more food than their population can consume. As a result, they compete for consumer food dollars. About 80 percent of every food dollar is spent for processing beyond the food itself, including transportation, packaging, and advertising. Potatoes are cheap; it is much more profitable to sell potato chips. Food companies introduce more than twelve thousand new food products—many of them candy, snacks, soft drinks, and desserts—into the American food supply each year. A typical supermarket stocks more than thirty thousand different food items, and manufacturers market them with about $30 billion worth of annual advertising. Marketing affects dietary choices. Thus, the changing food supply favors consumption of processed foods higher in energy and relatively lower in nutritional value than the basic foods from which they were derived.