In the 20th cent. diets have been transformed by refrigeration, improved and faster transportation, advances in food preservation, and new farming methods that prolong the growing season and increase the yield per acre. As a result, foods are available more regularly, items purchased in one season can be frozen and consumed in another, and prices have become more competitive. After World War II, increased advertising, particularly on television, and the growing number of households in which all adults are employed, contributed to an increased consumption of unhealthy fast foods. Efforts in the 1980s and 90s by health experts to educate the public about the importance of a healthy diet has had some impact. People are eating more fruits, grains, and vegetables, and less red meat, and are aware of the need to control their weight. The latter has given rise to many ineffective, and sometimes dangerous, fad diets that do not provide all of the necessary daily nutrients. Successful weight control requires a carefully planned regimen of exercise combined with a diet based on the nutrition information supplied by the U.S. Dept. of Agriculture's Food Guide Pyramid (see food pyramid).
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.