General guidelines for a healthy diet have been developed even though daily nutritional requirements, including those for essential nutrients, vary depending on age, sex, height, weight, physical activity, and the rate at which the body burns calories (metabolic rate). Recommended dietary allowances for protein, vitamins (see Vitamins), and minerals (see Minerals) are periodically published by The Food and Nutrition Board of the National Academy of Sciences–National Research Council and the U.S. Department of Agriculture. These allowances are intended to meet the needs of healthy people.

The U.S. Department of Agriculture also provides an interactive tool at My Plate. It enables people to enter information about themselves (their age, sex, activity level, and foods usually eaten) so that they can evaluate their diet and get recommendations about healthful foods and portion sizes that can help them reach and maintain a healthy weight. The amount of food needed each day from each food group varies depending on the person's energy needs.

In general, authorities recommend that fat intake be reduced to about 30% of calories or less and the intake of fruits, vegetables, and cereals be higher than most Americans eat. Drinking enough fluids is also important.

Last full review/revision July 2008 by Margaret-Mary G. Wilson, MD