Substances in food necessary for life. They include carbohydrates, fats, proteins, vitamins, minerals and water. Carbohydrates, fats and proteins provide energy, and vitamins and minerals are essential for the METABOLISM that uses this energy. Water, composing 60 percent of our total body weight, provides the medium in which chemical reactions take place.
The combination of processes by which the body takes in and uses food containing these nutrients, which includes digestion and metabolism, is called nutrition.
Nutrient-dense foods are those that provide substantial amounts of vitamins and minerals and relatively fewer calories, such as fruits and vegetables. The opposite of nutrient dense is calorie dense, which describes foods that mainly supply calories and relatively few nutrients. They are typically high in fat and/or sugar, such as white bread, pastries, ice cream or chocolate candy.
The Dietary Guidelines for Americans, released by the U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA) every five years, are the federal government’s science-based advice designed to help Americans choose diets that will meet nutrient requirements. The 2005 guidelines warned that many Americans consume more calories than they need without meeting recommended intakes for a number of nutrients.
Nutritional intake is of particular importance in adolescence because of rapid growth and development during this period, but several government and private studies have shown that while obesity among American children is escalating, consumption of Recommended Daily Allowance of critical foods and nutrients is on the decline. Adolescents with anorexia nervosa also rob their bodies of essential nutrients.
While anorexics do not take in enough food to provide adequate nutrients, people with binge-eating disorder usually eat large amounts of fats and sugars, which do not have a lot of vitamins or minerals, so they also may not get the right nutrients. The overweight or obese need to be wary of fad diets, which may not provide all of the nutrients the body needs.
U.S. Department of Health and Human Services, U.S. Department of Agriculture. Dietary Guidelines for Americans 2005. Washington: U.S. Government Printing Office, 2005. Available online. URL:http://www. health.gov/dietaryguidelines/dga2005/document. Downloaded on August 15, 2005.