Nutritional Requirements

Although daily nutritional requirements, including those for essential nutrients, depend on a person's age, sex, height, weight, and metabolic and physical activity, general guidelines for a healthy diet have been developed. The Food and Nutrition Board of the National Academy of Sciences--National Research Council and the U.S. Department of Agriculture periodically publish recommended dietary allowances for protein, vitamins (see Section 12, Chapter 154), and minerals (see Section 12, Chapter 155). These allowances are intended to meet the needs of healthy people.

The U.S. Department of Agriculture has also proposed the food guide pyramid as a guide to a balanced diet. This guide is intended to help people choose a diet that provides a balance of different types of food, supplies essential nutrients, and helps reduce the risk of such disorders as cancer, high blood pressure, coronary artery disease, and stroke. In this guide, the number of servings a day for each food group varies, depending on energy needs that range from 1,600 to more than 2,400 calories a day. For example, a person who consumes 1,600 calories a day could eat 6 servings from the bread group and 3 from the vegetable group, whereas a person who consumes 2,400 calories a day could eat 10 servings from the bread group and 5 from the vegetable group. In general, authorities recommend that fat intake be reduced to about 30% of calories and the intake of fruits, vegetables, and cereals be increased.