The USDA had also developed the food pyramid and the Four Food Groups. The 2005 guidelines are more specific than either of these earlier concepts and can be found at My Pyramid, a Web site maintained by the USDA.

Research has shown that eating a variety of healthy foods may help protect against heart disease and some cancers. Healthy eating also means including a variety of foods in your diet and watching portion sizes.

At least half of your grains (cereal, bread, rice and pasta) should be whole grains. The amount of grains you should have each day depends on your age, gender and how active you are. A 30-year-old woman who gets 30 to 60 minutes of exercise a day should consume 6 ounces of grains daily. A man of the same age and activity level should consume 9 ounces of grains daily.

It's important to know what constitutes a cup (or an ounce for grains and meats) to ensure that you get the recommended amount of each food group. Fruits and vegetable amounts are also given as cups in the guidelines.

The Dietary Guidelines say that a 2,000-calorie diet should include 2-1/2 cups of vegetables. A person who should consume more calories or fewer calories would need a different amount. Your diet should include dark green vegetables, orange vegetables, dry peas and beans, starchy vegetables and "other" vegetables (such as asparagus, cabbage, mushrooms and zucchini).

You can buy vegetables raw, canned or frozen -- all have the same nutrients.

Beans, eggs and nuts are interchangeable with meat, fish and poultry.

Other foods that are mostly oil include mayonnaise, salad dressings and soft margarine.