In the early 1990s the long-standing, traditional basic four food groups, consisting of meat, dairy products, grains, and fruits and vegetables, were reworked into the more balanced and healthy food guide pyramid. This pyramid has as its base the grain group; on the second level are the fruit and vegetable groups; on the third level are the meat and dairy groups; and at the top is the fats, oils, and sweets group.

Grain Group

At the base of the food guide pyramid are breads, cereals, rice, pasta, and other foods made from grain. Human beings need more daily servings of these foods than any others because grain-based foods provide B vitamins, iron, carbohydrates, and some protein. Six or more daily servings are recommended. A serving, for example, is one slice of bread, one ounce (28 grams) of dry cereal, or one half cup of cooked pasta.

Fruit Group and Vegetable Group

The sources of most vitamins and minerals belong to these two groups. They also provide fiber, which contains no nutrients but aids in moving food through the digestive system. Three to five servings of vegetables and two to four servings of fruit should be eaten every day. One half cup of any fruit or vegetable counts as one serving.

Dairy Group and Meat Group

On this level are two groups of foods, such as milk, cheese, poultry, fish, and eggs, that come mostly from animals; notable exceptions are nuts and dried beans. These groups are quite high in protein, calcium, iron, phosphorus, the B vitamins, and zinc. Two to three servings from each group are recommended daily. Eight ounces (227 grams) of milk or 3 ounces (85 grams) of meat, for example, count as a serving.

Fats, Oils, and Sweets Group

The top of the pyramid includes foods that may add pleasure to eating but provide only calories and little nutritional benefit to one's diet. These foods include salad dressings, cream, butter, margarine, sugars, soft drinks, and candies. They should be eaten only sparingly. The American Heart Association recommends that no more than 30 percent of one's daily calories be derived from fat.