The term diet refers to a person's pattern of eating and drinking. Diet is influenced by many factors, including income, culture, religion, geographic location, and lifestyle. A balanced diet contains food from several food groups and supplies the body with the energy and essential nutrients it needs (as defined by the Food Guide Pyramid and Dietary Reference Intakes).
The Food Guide Pyramid lists food categories and serving recommendations. Dietary Reference Intake values provide a range of dietary recommendations, including the Recommended Dietary Allowances (RDAs), which provide the daily intake needed to meet the needs of "nearly all healthy persons." Dietary recommendations, and how they are represented, vary around the world. Most, however, convey a common message: balance, variety, and moderation in food choices.
Brown, Judith (2002). Nutrition through the Life Cycle. Belmont, CA: Wadsworth.
United States Department of Agriculture, Food and Nutrition Center. "Food Guide Pyramid." Available from <http://nal.usda.gov/fnic>